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Popular Articles (January 2015)

Includes the top 50 most frequently downloaded documents for this publication according to the most recent monthly usage statistics.
  • 1. Harvesting Wireless Power: Survey of Energy-Harvester Conversion Efficiency in Far-Field, Wireless Power Transfer Systems

    Publication Year: 2014 , Page(s): 108 - 120
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2667 KB) |  | HTML iconHTML  

    The idea of wireless power transfer (WPT) has been around since the inception of electricity. In the late 19th century, Nikola Tesla described the freedom to transfer energy between two points without the need for a physical connection to a power source as an "all-surpassing importance to man". A truly wireless device, capable of being remotely powered, not only allows the obvious freedom of movement but also enables devices to be more compact by removing the necessity of a large battery. Applications could leverage this reduction in size and weight to increase the feasibility of concepts such as paper-thin, flexible displays, contact-lens-based augmented reality, and smart dust, among traditional point-to-point power transfer applications. While several methods of wireless power have been introduced since Tesla's work, including near-field magnetic resonance and inductive coupling, laser-based optical power transmission, and far-field RF/microwave energy transmission, only RF/microwave and laser-based systems are truly long-range methods. While optical power transmission certainly has merit, its mechanisms are outside of the scope of this article and will not be discussed. View full abstract»

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  • 2. Substrate Integrated Waveguide Filters: Design Techniques and Structure Innovations

    Publication Year: 2014 , Page(s): 121 - 133
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4647 KB)  

    Because of the inherent structural flexibility in coupling design and topological arrangement, substrate integrated waveguide (SIW) filter topologies enjoy better out-of-band frequency selectivity and/or in-band phase response with the allocation of finite transmission zeros (FTZs). In the first article in this series, basic design rules and fundamental electrical characteristics have been presented that indicate the superior performances of SIW structures and their filter applications. Advanced design techniques and innovative structure features have recently been reported in a large number of publications. They include cross couplings realized by physical and nonphysical paths and SIW filters with dual-mode or multimode techniques. Miniaturization-enabled techniques including low-temperature cofired ceramic (LTCC) technology have been developed and applied to the development of SIW filters to reduce the size for low-gigahertz applications using nontransverse electromagnetic (non-TEM) modes. Wideband SIW filters, multiband SIW filters, and reconfigurable SIW filters have also been reported by various research groups. This article reviews these advanced and innovative SIW filter technologies, and related examples are presented and discussed. View full abstract»

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  • 3. RF MEMS switches and switch circuits

    Publication Year: 2001 , Page(s): 59 - 71
    Cited by:  Papers (363)  |  Patents (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1365 KB) |  | HTML iconHTML  

    MEMS switches are devices that use mechanical movement to achieve a short circuit or an open circuit in the RF transmission line. RF MEMS switches are the specific micromechanical switches that are designed to operate at RF-to-millimeter-wave frequencies (0.1 to 100 GHz). The forces required for the mechanical movement can be obtained using electrostatic, magnetostatic, piezoelectric, or thermal designs. To date, only electrostatic-type switches have been demonstrated at 0.1-100 GHz with high reliability (100 million to 10 billion cycles) and wafer-scale manufacturing techniques. It is for this reason that this article will concentrate on electrostatic switches View full abstract»

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  • 4. Composite right/left-handed transmission line metamaterials

    Publication Year: 2004 , Page(s): 34 - 50
    Cited by:  Papers (368)  |  Patents (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3109 KB) |  | HTML iconHTML  

    Metamaterials are artificial structures that can be designed to exhibit specific electromagnetic properties not commonly found in nature. Recently, metamaterials with simultaneously negative permittivity (/spl epsiv/) and permeability (μ), more commonly referred to as left-handed (LH) materials, have received substantial attention in the scientific and engineering communities. The unique properties of LHMs have allowed novel applications, concepts, and devices to be developed. In this article, the fundamental electromagnetic properties of LHMs and the physical realization of these materials are reviewed based on a general transmission line (TL) approach. The general TL approach provides insight into the physical phenomena of LHMs and provides an efficient design tool for LH applications. LHMs are considered to be a more general model of composite right/left hand (CRLH) structures, which also include right-handed (RH) effects that occur naturally in practical LHMs. Characterization, design, and implementation of one-dimensional and two-dimensional CRLH TLs are examined. In addition, microwave devices based on CRLH TLs and their applications are presented. View full abstract»

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  • 5. Green Communications: Digital Predistortion for Wideband RF Power Amplifiers

    Publication Year: 2014 , Page(s): 84 - 99
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3357 KB)  

    The RF PA, as one of the most essential components in any wireless system, suffers from inherent nonlinearities. The output of a PA must comply with the linearity requirement specified by the standards. Due to its satisfactory linearization capability, DPD has been widely accepted as one of the fundamental units in modern and future wideband wireless systems. With the help of this flexible digital technology, the inherent linearity problem of PAs operating in the saturation region can be significantly improved, which enables us, the wireless engineers, to create more suitable RF transceiver architectures to provide wireless access with better user experience (linearity perspective) and less power waste (power efficiency perspective). This moves us one more step towards the ultimate green communications. In this article, we discussed the DPD techniques in the context of linearizing nonlinear RF PAs. As the computing-horsepower and the transistor-density of digital IC increases while the cost per transistor decreases, the concept that uses digital enhancement techniques to eliminate active analog imperfects will gain more attention from both industry and academia. View full abstract»

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  • 6. Wireless Data Center Management: Sensor Network Applications and Challenges

    Publication Year: 2014 , Page(s): S45 - S60
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5729 KB)  

    The modern data centers (DCs) are essential to fulfilling ever-evolving computational demands around cloud computing, big data, and IT infrastructure. These DCs are facilities (Figure 1) that house computer systems and associated components such as networking and storage systems. To operate a DC, power supplies, network connections, environmental controls (e.g., air conditioning, humidity), and security infrastructure are needed. Technology and business challenges such as virtualization, load consolidation, real-time troubleshooting, and service-level guarantees require a robust and adaptive server management plan for enterprise. The majority of DC issues are related to overutilization of resources, application failures, data security, power usage effectiveness (PUE), and infrastructure costs. This requires proactive solutions that are business intelligent and built over a network of sense points that are guaranteed to deliver reliable trends and measurements in a reliable and timely fashion. Since it is expensive to build new DCs, the best option is to improve usage of an existing facility through lower infrastructure overhead to deliver better resource management. An optimal sensor network would perform real-time sensor-data collection and deliver a) improved server rack utilization, b) improved DC cooling, and c) improved loadbalancing through dynamic capping of thermally constrained systems. View full abstract»

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  • 7. Advancements at the Lower End: Advances in HF, VHF, and UHF Systems and Technology

    Publication Year: 2015 , Page(s): 28 - 49
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (7285 KB)  

    In the March 2002 issue of IEEE Transactions on Microwave Theory and Techniques (T-MTT), Frederick Raab, chair and founder of the highfrequency (HF), very high frequency (VHF), ultrahigh frequency (UHF) technology technical committee of the IEEE Microwave Theory and Techniques Society (Technical Committee 17), organized an extensive overview paper "HF, VHF, and UHF Systems and Technology" [1]. The paper started with the early-20th-century notion that frequencies above approximately 1.5 MHz (200 m and down) were useless for communications, a fact soon discovered to be incorrect as experimenters and amateur radio enthusiasts showed the utility of the higher frequencies. The paper reviewed HF through UHF communication techniques and technologies, various propagation modes, and a number of systems and applications below 1,000 MHz. There have been many advances in this frequency range in the intervening years, some of them quite striking, as well as new applications and other applications not mentioned in the paper; updating the paper on HF, VHF, and UHF technology is the major focus of this article. In addition to updates on some of the material in the original paper, new technologies and/or a better understanding of electromagnetic (EM) behavior have occurred, and these are included in this article. View full abstract»

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  • 8. Stacked Yagi-Uda Array for 2.45-GHz Wireless Energy Harvesting

    Publication Year: 2015 , Page(s): 67 - 73
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2469 KB)  

    Wireless energy harvesting is currently a popular topic in radiofrequency (RF) engineering. Electromagnetic (EM) energy coming from different kinds of sources has to be collected by the harvester and efficiently converted into dc power. Practical applications include wireless charging systems and dc powering of RF identification (RFID) chips. Space applications were also investigated. Therefore, the third Wireless Energy Harvesting Student Design Competition was organized during the 2014 IEEE Microwave Theory and Techniques Society International Microwave Symposium (IMS2014) in Tampa, Florida. View full abstract»

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  • 9. Linear Doherty PA at 5 GHz

    Publication Year: 2015 , Page(s): 89 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1464 KB)  

    At the 2014 International Microwave Symposium (IMS2014) in Tampa, Florida, the power amplifier (PA) design competition celebrated its tenth anniversary. Back in 2004, it was the first student design competition that the IEEE Microwave Theory and Techniques Society (MTT-S) organized and, since then, the only one that has been held regularly every year. We started to participate in this competition in 2012, which also happened to be the year when a significant change in the competition rules was adopted. Starting in 2012, the power-added efficiency (PAE) in the figure of merit (FOM) that is used to evaluate the PAs, FOM = PAE/4?f, was measured at a power level at which the intermodulation distortion (IMD) that the PA produces from a two-tone excitation first exceeds 30 dBc. With that new rule, not only did linearity start to play a major role but also the test signal changed from continuous wave (CW) to a modulated signal with a peak to average ratio of 3 dB. View full abstract»

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  • 10. Hassle-Free Vitals: BioWireleSS for a Patient-Centric Health-Care Paradigm

    Publication Year: 2014 , Page(s): S25 - S33
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2012 KB)  

    Continuous monitoring of vital information via a wireless medium has become an integral part of next-generation health-care technologies. The benefits of a wireless monitoring technique include facilitating in-home care services, reduction of the cost of frequent visits to hospitals, and lightening of the burden to the elderly persons. The development of miniature, lightweight, and energy-efficient circuit solutions for biomedical sensor applications has been made possible by the tremendous recent advancements in health-care monitoring technologies, micro- and nanofabrication processes, and wireless communications. Exuberant growth of the wireless sensor networks has opened up a new and innovative application of wireless technology in health care. The advancement of wireless technology has led to the development of the recently proposed comprehensive patient monitoring systems such as wireless body area network (WBAN) and body sensor network (BSN). Implantable and wearable sensors are integral components of these networks and are employed for monitoring various levels of physiological activities. Wireless sensor technology provides an effective tool for instant access to patient data, laboratory test results, and clinical histories as well as insurance information, thereby ensuring immediate health care in case of emergency, eliminating the lengthy clinical decision. This biomedical wireless technology has resulted in a new health-care concept known as telemedicine, which facilitates the monitoring of in-home patient care by incorporating smart medical devices and WBANs. In this scheme, implantable and wearable sensors are placed within the vicinity of the patient's body and various physiological parameters are monitored and transmitted wirelessly to a nearby hub station and subsequently to the remote health-care provider via a secure wireless communication network. The telemedicine platform can also be configured for identification of the object location, medicin- reminder, or emergency alert in case of any sign of fatal disease. As a result of the recent developments in biomedical wireless technologies, the traditional clinic-centric health care is giving way to a patient-care centric health-care concept. This translational health-care concept facilitates the multidirectional integration of basic research, patient-oriented research, and population-based research, with the long-term aim of improving the health of the public. However, the successful integration of this new health-care paradigm hinges on the proper interpretation, storage, and dissemination of the large data sets generated by the all implantable and wearable devices within the wireless network. View full abstract»

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  • 11. A Compact L-Band Bandpass Filter with RF MEMS-Enabled Reconfigurable Notches for Interference Rejection in GPS Applications

    Publication Year: 2015 , Page(s): 81 - 88
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2342 KB)  

    In light of today's crowded radio spectrum and the high level of receiver sensitivity required to receive very weak signals, mitigating interference (cosite, intentional jamming, or from other sources) has become a very important topic of research. The recent controversy regarding the use of spectrum close to the global positioning system (GPS) bands is the motivation for the IEEE Microwave Theory and Techniques Society 2014 International Microwave Symposium (IMS2014) Tunable Radio-Frequency (RF) Microelectromechanical Systems (MEMS) Filter Student Design Competition, held in Tampa, Florida. Although there are frequency bands reserved for GPS, there is sometimes interference from undesired signals from a variety of sources, such as radio emissions in adjacent bands, intentional/unintentional jamming, and naturally occurring space weather. Ensuring the continuity of GPS service requires the protection of its spectrum from interference. This competition was intended to interest students in the design of innovative RF front-end solutions to address this issue. This article describes the work of the winners of the first-place award. View full abstract»

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  • 12. Multispectrum Signal Transmitters: Advances in Broadband High-Efficiency Power Amplifiers for Carrier Aggregated Signals

    Publication Year: 2014 , Page(s): S14 - S24
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4479 KB)  

    This article described recent advances in Doherty power amplifiers (DPAs) with extended bandwidth for use in future radio transmitters intended to support carrier aggregation signal transmission. It provided a review of several configurations of two-way (using symmetrical and asymmetrical drain supply voltages) and three-way DPAs. Furthermore, it identified various approaches to ensure proper load modulation over extended bandwidth by incorporating novel combining networks. It also discussed the additional challenges associated with the linearizability of DPAs when driven with interband aggregated signals. View full abstract»

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  • 13. Design of 1:4 Ultrawideband Hybrid Transmission-Line Balun

    Publication Year: 2015 , Page(s): 122 - 126
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1705 KB)  

    This article presents the 1:4 wideband balun based on transmission lines that was awarded the first prize in the Wideband Baluns Student Design Competition. The competition was held during the 2014 IEEE Microwave Theory and Techniques Society (MTT-S) International Microwave Symposium (IMS2014). It was initiated in 2011 and is sponsored by the MTT-17 Technical Coordinating Committee. The winner must implement and measure a wideband balun of his or her own design and achieve the highest possible operational frequency from at least 1 MHz (or below) while meeting the following conditions: ? female subminiature version A (SMA) connectors are used to terminate all ports ? a minimum impedance transformation ratio of two ? a maximum voltage standing wave ratio (VSWR) of 2:1 at all ports ? an insertion loss of less than 1 dB ? a common-mode rejection ratio (CMRR) of more than 25 dB ? imbalance of less than 1 dB and 2.5?. View full abstract»

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  • 14. Multiport Technology: The New Rise of an Old Concept

    Publication Year: 2014 , Page(s): S34 - S44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2345 KB)  

    Modern society has shown a large demand for ubiquitous and wireless connectivity, information transmission with high data rates, and precise sensors for any kind of physical dimension. Nevertheless, the frequency spectrum is limited and bandwidth restricted by regulatory issues. Over the last few years, a continuous rise in operating frequency linked to rising bandwidth has been observed. For short-range operation, the license-free industrial, scientific, and medical (ISM) bands beyond 100 GHz are becoming more a focus for practical applications. At the same time, microwave monolithic integrated circuit (MMIC) processes must keep up with this rise in operating frequency, requiring high investment costs in new MMIC technology. Initially, before the cost of this technology becomes reasonable, alternative hybrid circuit concepts are needed as a door opener for mass-market applications. For this purpose, an old frontend concept is getting increased support, leading to a constant growth of an originally small, but worldwide, community: multiport technology. This article provides an overview of the basics, possible applications, and specific calibration procedures for the six-port circuit, which is the most common multiport implementation of this promising architecture. View full abstract»

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  • 15. Beyond the Smith Chart: A Universal Graphical Tool for Impedance Matching Using Transformers

    Publication Year: 2014 , Page(s): 100 - 109
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1911 KB)  

    The topic of impedance transformation and matching is one of the well-established and essential aspects of microwave engineering. A few decades ago, when discrete radio-frequency (RF) design was dominant, impedance matching was mainly performed using transmission-lines techniques that were practical due to the relatively large design size. As microwave design became possible using integrated on-chip components, area constraints made L-C section matching (using lumped passive elements) more practical than transmission line matching. Both techniques are conveniently visualized and accomplished using the well-known graphical tool, the Smith chart. View full abstract»

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  • 16. RF and Microwave Links: The MTT Society and the Amateur Radio Community

    Publication Year: 2015 , Page(s): 50 - 63
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5037 KB)  

    Microwave and RF engineers are, by their very nature, experimenters.This experimentation comes in various guises; the traditional definition is the engineer working tirelessly (and often in obscurity) on circuits on the workbench, but other equally valid definitions include playing what-if scenarios with microwave/RF computer-aided design (CAD) input variables or even trying various input parameters to explore the limits of a mathematical theory. Through experimentation,many advances in technology have been found, with new advances being reported each day in the literature. View full abstract»

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  • 17. CMOS Differential Ring Oscillators: Review of the Performance of CMOS ROs in Communication Systems

    Publication Year: 2013 , Page(s): 97 - 109
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4372 KB) |  | HTML iconHTML  

    The integrated differential ring oscillator (DRO) in complementary metal oxide semiconductor (CMOS) technology has been used in numerous products for a long time. Its presence has been extended to high-speed clock and data recovery (CDR) circuits for optical communication, analog and digitally controlled oscillators, frequency dividers of high-frequency synthesizers, clock generators of digital circuits, analog-to-digital converters (ADCs), and many more applications [1]-[5]. Implementations of these ring oscillators are seen in emerging technologies such as ultrawideband (UWB) and radio frequency identification (RFID) as well as wireless sensor networks (WSNs) and short-range communication devices [6], [7]. The DRO is a good design choice for integrated circuit (IC)designers because of its continued use in different bulk CMOS technologies. This article presents implementation techniques and performance comparisons of the DRO as a CMOS voltage-controlled oscillator (VCO) in low radio frequency (RF) bands, along with presentation and discussion of a number of circuit approaches. View full abstract»

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  • 18. A Mircostrip Circuit Tool Kit App with FDTD Analysis Including Lumped Elements

    Publication Year: 2015 , Page(s): 74 - 80
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2621 KB)  

    At the 2014 IEEE Microwave Theory and Techniques Society (MTT-S) International Microwave Symposium (IMS2014), the Apps for MTT Student Design Contest was held,sponsored by the Microwave Field Theory (MTT-15) Technical Committee. One objective of the design contest is to take advantage of the growing computing capacity of smart handheld and mobile devices to promote their use for the computer-aided analysis and design of microwave components and circuits. With the rapid development of recent iOS and Android smart phones or pads, some advanced scientific computation programs can now be executed on these portable devices. These handy devices can also deal with microwave circuit calculations if the applications (apps) are well designed. Since these devices are always accessible, it may be more convenient for engineers and students to analyze and design microwave circuits on the phones or pads directly. Note that full-wave, three-dimensional (3-D) simulations for complicated microwave circuits usually require a large amount of memory and a central processing unit with high performance, so it may be difficult to run full-wave 3-D simulations on portable smart devices. View full abstract»

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  • 19. Substrate Integrated Waveguide Filter: Basic Design Rules and Fundamental Structure Features

    Publication Year: 2014 , Page(s): 108 - 116
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2732 KB)  

    The electromagnetic (EM) spectrum is becoming more crowded, and it is densely populated with various wireless signals and parasitic interferers in connection with communication and sensing services. Increasingly sophisticated radio-frequency (RF), microwave, and millimeter-wave filters are required to enable the selection and/or rejection of specific frequency channels. This will occur in future generations of the wireless system, such as the current hotly debated fifth-generation communication systems, where the spectral channelization of a heterostructured wide-band signals will be critical in support of a host of coexisting bandwidths or speeds and applications. Bandpass filters have been the most useful and popular types for such applications and are the most difficult to design and develop in practice. Other types of filters such as notch (stopband) and lowpass filters have also been widely used in many systems, and their design is generally perceived less critical with respect to band-pass filters. This article will focus on the presentation and discussion of bandpass filters. Design factors or parameters of filters, such as selectivity, cost, miniaturization, sensitivity to environmental effects (temperature and humidity, for example), and power handling, combined with predefined in-band and out-of-band performance metrics, are critical specifications of the design with respect to the development of RF and microwave front ends. This is indispensable for the efficient utilization of frequency spectrum resources and the cost-effective enhancement of wireless system performances. View full abstract»

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  • 20. Substrate Integrated Waveguide Filters: Practical Aspects and Design Considerations

    Publication Year: 2014 , Page(s): 75 - 83
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2063 KB)  

    In the current literature, the majority of research work reported on substrate integrated waveguide (SIW) filters has focused on the development of physical topologies as well as design and realization techniques for filter specifications and electrical parameters. The practical and successful implementation of SIW filters requires special consideration of mechanical and thermal properties during the design and processing stages. These properties include the effects of ambient operating environment, average, and peak power-handling capabilities as well as design and production economics, including labor costs, skilled labor availability, mass-production issues, and projected production delivery rates [1]. Bandpass filters are more concerned with those practical aspects as their in-band and out-of-band performance are much more sensitive than other types of filters to those mechanical and thermal issues. View full abstract»

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  • 21. Terahertz Plasmonics: Good Results and Great Expectations

    Publication Year: 2014 , Page(s): 43 - 50
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3133 KB)  

    The terahertz (THz) range is the next frontier of electronics and optoelectronics with potential applications ranging from imaging, space communications, computing, quality control, and homeland security to biotechnology and medicine. At THz frequencies, the electron inertia becomes important, providing delay between the applied voltage and electron velocity and current. When the electron collisions with impurities and lattice vibrations are infrequent, this delay leads to oscillations of the electronic density (called plasma waves) with the transistor channels serving as resonant cavities for the plasma waves. In the collision-dominated regime, the plasma waves are overdamped but still play a role by dramatically changing the electron distribution in the device channels at THz frequencies. The resonant regime can be used to generate THz radiation. Both resonant and overdamped plasma waves enable other THz electronic devices, such as detectors, mixers, and phase shifters. Periodic (symmetrical and asymmetric) plasmonic structures are especially promising for generation and detection of THz radiation. In this article, we review the state of the art of the plasma-wave electronics for silicon, III-V, III-N, and graphene semiconductor devices and project future performance of plasma-wave THz devices. View full abstract»

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  • 22. WebLab: A Web-Based Setup for PA Digital Predistortion and Characterization [Application Notes]

    Publication Year: 2015 , Page(s): 138 - 140
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (978 KB)  

    The WebLab that is described here was initially motivated by the 2014 IEEE Microwave Theory and Techniques Society International Microwave Symposium's (IMS2014's) Student Design Competition on Digital Predistortion (DPD) Linearization, described in "Accurate Linearization with Low-Complexity Models Using Cascaded Digital Predistortion Systems," by Barradas et. al on page 94 in this issue of IEEE Microwave Magazine. To make a comparison of DPD algorithm performance, it is necessary to have one device under test (DUT), a Doherty power amplifier (PA), and one measurement setup for everybody to use. This was not a problem for the finals of the competition because the competitors would all be physically present at the same location. However, for the preparations starting half a year in advance, this posed a serious problem. The solution we implemented takes advantage of the fact that most universities today provide a decent Internet connection for their employees and students. A remotely accessible WebLab seemed to be a viable solution to the problem of letting the competitors practice on the actual DUT using the same measurement setup before the final competition at IMS2014. We decided to construct a Web-based remote-controlled PA measurement setup that allowed any user (not only the competitors) to upload his or her own input data and download the resulting measured output data. The Web page and instructions for using it can be found at http://dpdcompetition.com. View full abstract»

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  • 23. Elastic Reactance [Microwave Bytes]

    Publication Year: 2015 , Page(s): 21 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1793 KB)  

    I suppose it could be regarded as appropriate, given nearly a three-year hiatus, to survey the microwave scene with my ever-more jaundiced eye. I do so, however, with brevity and the consumption of some humble pie as some (not all) of my former targets are alive, well, and going strong. One such, I have to admit, is gallium nitride (GaN) technology, which appears to be triumphing against the odds of cost and becoming the default option for gigahertz power amplifier (PA) designers. So be it; GaN certainly makes radio-frequency PAs (RFPAs) easier to design, although this respite will no doubt be short lived as the specifications adapt to keep us in the forefront of difficulty and on the edge of impossibility. Such is life, but I believe it is still a silicon world, as dramatically shown by the domination of silicon and complementary metal-oxide-semiconductor technology in the millimetric zone. If we can make complete transceivers, not to mention multi watt PAs, with decent efficiency at 100 GHz, a passing observer might question the need for the exotic compound semiconductors that still dominate the world above 1 GHz. Time will tell. View full abstract»

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  • 24. RF MEMS-CMOS Device Integration: An Overview of the Potential for RF Researchers

    Publication Year: 2013 , Page(s): 39 - 56
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5257 KB) |  | HTML iconHTML  

    Over the past decades, a great deal of progress has been made in the development of semiconductor manufacturing processes. This in turn has made possible the monolithic integration of microelectromechanical systems (MEMS) devices with driving, controlling, and signal processing CMOS electronics [1][4]. There have been several successful well known commercial examples of integrated MEMS-CMOS devices, including the Analog Devices ADXL accelerometers [5], the Texas Instruments digital micromirror device (DMD) [6], the STMicroelectronics accelerometers and gyroscopes [6], and SiTime vacuum-encapsulated resonators [7]. More recently, Cavendish Kinetic [8] and WiSpry [9] launched their RF MEMS switches fabricated through MEMS-CMOS integration. While several techniques for MEMS-CMOS integrations have been widely employed for sensor and accelerometer applications, most of the work reported in literatures on RF MEMS has focused on devices fabricated using conventional surface micromachining techniques. It is the objective of this article to provide RF researchers with an overview of the potential of integrating MEMS with CMOS for RF MEMS applications. View full abstract»

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  • 25. Inverse Class-F Design Using Dynamic Loadline GaN HEMT Models to Help Designers Optimize PA Efficiency [Application Notes]

    Publication Year: 2014 , Page(s): 134 - 147
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (9154 KB)  

    Simulation of power amplifiers (PAs) for modern wireless base station and small cell systems is an essential part of the design process. At a cell site, the PA consumes the bulk of the dc power, generates the most heat, and thus represents the greatest operational cost. Maximum PA efficiency is a necessity to manage these costs, which is a sizeable challenge in a PA that also must be highly linear to support the complex multilevel modulation types and wide bandwidths used for current and developing wireless transmission standards. Accurate simulation allows the PA designer to meet these challenges by exploring the available design options and then optimizing the circuit that is selected for the application. View full abstract»

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  • 26. Space solar power programs and microwave wireless power transmission technology

    Publication Year: 2002 , Page(s): 46 - 57
    Cited by:  Papers (81)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1429 KB) |  | HTML iconHTML  

    Future large-scale space solar power (SSP) will form a very complex integrated system of systems requiring numerous significant advances in current technology and capabilities. Ongoing technology developments have narrowed many of the gaps, but major technical, regulatory, and conceptual hurdles remain. Continuing systems concept studies and analyses will be critical to success, as will following a clear strategic R&T road map. This road map must assure both an incremental and evolutionary approach to developing needed technologies and systems is followed, with significant and broadly applicable advances with each increment. In particular, the technologies and systems needed for SPS must support highly leveraged applicability to needs in space science, robotic and human exploration, and the development of space. Considerable progress has been made in the critical area of microwave power transmission. At 5.8 GHz, DC-RF converters with efficiencies over 80% are achievable today. Rectennas developed at 5.8 GHz have also been measured with efficiencies greater than 80%. With optimized components in both the transmitter and rectenna, an SPS system has the potential of a DC-to-DC efficiency of 45%. View full abstract»

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  • 27. Accurate Linearization with Low-Complexity Models Using Cascaded Digital Predistortion Systems

    Publication Year: 2015 , Page(s): 94 - 103
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3578 KB)  

    Power efficiency is one of the main concerns in modern radio frequency (RF) power amplifier (PA) design. However, efficiency-driven designs typically impose operation of these devices in a compressed mode [1]. When operating in this region, the amplifiers will behave nonlinearly and produce a distorted output signal [1]. This distortion produces new spectral components at the PAs' output that are outside the bandwidth of the input signal, so the distorted output signal has a wider bandwidth than the input signal. This bandwidth enlargement effect, called "spectral regrowth," is undesired in RF transmitters due to wireless systems' spectral mask regulations [2]. View full abstract»

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  • 28. A Novel Low Phase Noise X-Band Oscillator

    Publication Year: 2015 , Page(s): 127 - 135
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2968 KB)  

    In this article, we presented an X-band oscillator based on a novel CCMR using SIW technology. The measured results show that the proposed oscillator using active complementary coupled metamaterial has low phase noise and a good FOM for a given size and dc power consumption. View full abstract»

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  • 29. The Doherty power amplifier

    Publication Year: 2006 , Page(s): 42 - 50
    Cited by:  Papers (83)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1873 KB) |  | HTML iconHTML  

    In this article, we show that the Doherty amplifier is capable of delivering the stringent requirements of the base station power amplifiers. We explain the operation principles, including both linearity and efficiency improvements, and the basic circuit configuration of the amplifier. Advanced design methods to operate across wide bandwidth and improve the linearity are also described. For verification, the Doherty amplifier is implemented using laterally diffused metal oxide semiconductor (LDMOS) transistors and measured using a WCDMA 4FA signal. These results show that the Doherty amplifier is a promising candidate for base station power amplifiers with wide bandwidth, high efficiency, and linearity View full abstract»

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  • 30. Submillimeter-Wave Radar: Solid-State System Design and Applications

    Publication Year: 2014 , Page(s): 51 - 67
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (7227 KB)  

    For decades, the principal role of microwave engineering techniques in the submillimeter (submm)-wave, or terahertz (THz), regime, spanning about 300 GHz-3 THz, has been to optimize the performance of components and systems used in molecular spectroscopy measurements for astronomy, earth science, and plasma diagnostics [1]. THz applications beyond spectroscopy have been much slower to develop. Ultrahigh bandwidth communication at THz frequencies may have the most powerful market forces to support it, but no systems have been deployed beyond the prototype stage, likely because of the unavailability of commercial submm-wave components, challenges with integrating them with existing communications hardware, and the often severe atmospheric attenuation. View full abstract»

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  • 31. Power without wires

    Publication Year: 2011 , Page(s): S64 - S73
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3005 KB) |  | HTML iconHTML  

    This article presents the history of WPT and the various technologies and applications of this exciting technology. In the near future, standardization and regulation will be of importance to realizing WPT based products for commercial applications. The WPC has defined a standard for inductive coupling and members of this group have released conforming products. There are, as yet, no standards or regulation for resonant coupling and MPT technologies. In Japan, a technical forum known as Broadband Wireless Forum has been established to discuss the future of WPT. SPS researchers have also submitted a proposal for WPT to the International Telecommunication Union (ITU). In the IEEE MTT Society, the Technical Committee MTT-26 Wireless Energy Transfer and Conversion was established in June, 2011 to discuss the future of WPT. View full abstract»

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  • 32. A Dual-Frequency Ultralow-Power Efficient 0.5-g Rectenna

    Publication Year: 2014 , Page(s): 109 - 114
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1174 KB) |  | HTML iconHTML  

    The second annual Student Wireless Energy Harvesting (WEH) Design Competition was held during the 2013 IEEE Microwave Theory and Techniques Society (MTT_S) International Microwave Symposium (IMS2013) in Seattle, Washington, United States. This year, the competition parameters were modified from those of last year [1], and a new figure of merit (FoM) was established. The overall goal of the competition was to demonstrate low-mass hardware that can efficiently receive and rectify extremely low-incident power densities at two frequencies, with a fixed dc load. As the radio-frequency (RF) environment gets more saturated with spurious power, designs from this competition will become a feasible way to energize ultralow-powered or low-duty-cycle hard-to-reach sensors. Concepts such as Internet-of-Things, in which small ubiquitous devices and sensors will log data and send it to the cloud, could benefit from wireless energy harvesters. These sensors will not have convenient ways to stay powered unless power harvesting circuits are used for the sensor hardware. View full abstract»

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  • 33. 60 GHz Wireless: Up Close and Personal

    Publication Year: 2010 , Page(s): 44 - 50
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2816 KB) |  | HTML iconHTML  

    To meet the needs of next-generation high-data-rate applications, 60 GHz wireless networks must deliver Gb/s data rates and reliability at a low cost. In this article, we surveyed several ongoing challenges, including the design of cost-efficient and low-loss on-chip and in-package antennas and antenna arrays, the characterization of CMOS processes at millimeter-wave frequencies, the discovery of efficient modulation techniques that are suitable for the unique hardware impairments and frequency selective channel characteristics at millimeter-wave frequencies, and the creation of MAC protocols that more effectively coordinate 60 GHz networks with directional antennas. Solving these problems not only provides for wireless video streaming and interconnect replacement, but also moves printed and magnetic media such as books and hard drives to a lower cost, higher reliability semiconductor form factor with wireless connectivity between and within devices. View full abstract»

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  • 34. Promising Future of Metamaterials

    Publication Year: 2012 , Page(s): 39 - 56
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (10519 KB) |  | HTML iconHTML  

    This article summarized and reviewed the realization and applications of the waveguide-based metamaterial structures. In particular, an overview of the existing metamaterial elements was presented. We discussed the possible solutions to enable wave propagation below the waveguide cutoff frequency by loading these elements. Then a detailed analysis on those waveguide unit-cells loaded with different metamaterial elements was provided based on HFSS simulation. Various guided and radiated microwave applications based on these novel metamaterial-based waveguide structures were presented. Those obtained simulation and experimental results were found to be in good agreement with the theoretical prediction. These applications also demonstrate that the combination of waveguide structure and metamaterials offers an excellent alternative approach to the design of miniaturized and high-performance microwave components. Waveguide has high-power handling capability and high Q-factor. It also provides a uniform and lossless ε-negative (μ-negative) environment when operated based on the TE modes (TM modes) below the cutoff frequency. This is a promising and potentially rewarding research topic. We are looking forward to achieving more truly high-performance metamaterial devices by taking advantages of these features in the near future. View full abstract»

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  • 35. A Wideband Balun for HF, VHF, and UHF Applications

    Publication Year: 2014 , Page(s): 86 - 91
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (865 KB) |  | HTML iconHTML  

    There is an industry need for wideband baluns to operate across several decades of bandwidth covering the HF, VHF, and UHF spectrum. For readers unfamiliar with the term "balun," it is a compound word that combines the terms balanced and unbalanced. This is in reference to the conversion between a balanced source and an unbalanced load, often requiring an impedance transformation of some type. It's common in literature to see the terms "balanced" and "unbalanced" used interchangeably with the terms "differential" and "single-ended," and this article will also share this naming convention. These devices are particularly useful in network matching applications and can be constructed at low cost and a relatively small bill of materials. Wideband baluns first found widespread use converting the balanced load of a dipole antenna to the unbalanced output of a single-ended amplifier. These devices can also be found in solid-state differential circuits such as amplifiers and mixers where network matching is required to achieve the maximum power transfer to the load. In the design of RF power amplifiers, wideband baluns play a critical role in an amplifier's performance, including its input and output impedances, gain flatness, linearity, power efficiency, and many other performance characteristics.This article describes the theory of operation, design procedure, and measured results of the winning wideband balun presented at the 2013 IEEE Microwave Theory and Techniques Society (MTT-S) International Microwave Symposium (IMS2013), sponsored by the MTT-17 Technical Coordinating Committee on HF-VHF-UHF technology. The wideband balun was designed to deliver a 4:1 impedance transformation, converting a balanced 100 Ω source to an unbalanced 25 Ω load. It was constructed using a multiaperture ferrite core and a pair of bifilar wires with four parallel turns. View full abstract»

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  • 36. The Sound the Air Makes: High-Performance Tunable Filters Based on Air-Cavity Resonators

    Publication Year: 2014 , Page(s): 83 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3239 KB)  

    Tunable filters have a wide range of applications from software-defined radio to reconfigurable satellite payloads. They are a key building block for any flexible transceivers. A variety of tunable filter technologies can be found in the literature. Examples include: planar tunable filters employing solid-state or microelectromechanical systems (MEMS) varactors [1]-[6], and ferroelectric variable capacitor tuned coaxial filters [7]. The choice of technology is driven by the application. In this article, we focus on applications requiring high performance, including low loss, high-power handling capability, and high stability, mainly for communications satellites or wireless base stations. These requirements immediately rule out any low-quality factor (Q) technologies. For instance, besides low Q, planar-type tunable filters typically suffer from poor selectivity and transmission-response variation over the tuning range. Technologies based on substrate-integrated-waveguide (SIW) offer better Q than microstrip circuits and advantage in packaging [8]-[10]. However, in most cases, their Q is comparable to strip-line circuits with the same volume. Air-cavity resonators, on the other hand, offer high-Q in the range of thousands to tens of thousands and high-power handling and are therefore one of the obvious choices. The addition of each requirement, such as power, selectivity, vibration, and temperature stability, further limits available choices. We are not aware of an existing technology that satisfies all these requirements. The search for a viable solution for the targeted high-end applications is indeed a difficult journey, with years of experience accumulation from past good and bad designs. View full abstract»

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  • 37. High-Q Tunable Filters: Challenges and Potential

    Publication Year: 2014 , Page(s): 70 - 82
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6399 KB)  

    High-Q tunable filters are in demand in both wireless and satellite applications. The need for tunability and configurability in wireless systems arises when deploying different systems that coexist geographically. Such deployments take place regularly when an operator has already installed a network and needs to add a new-generation network, for example, to add a long-term evolution (LTE) network to an existing third-generation (3G) network. The availability of tunable/reconfigurable hardware will also provide the network operator the means for efficiently managing hardware resources, while accommodating multistandards requirements and achieving network traffic/capacity optimization. Wireless systems can also benefit from tunable filter technologies in other areas; for example, installing wireless infrastructure equipment, such as a remote radio unit (RRU) on top of a 15-story high communication tower, is a very costly task. By using tunable filters, one installation can serve many years since if there is a need to change the frequency or bandwidth, it can be done through remote electronic tuning, rather than installing a new filter. Additionally, in urban areas, there is a very limited space for wireless service providers to install their base stations due to expensive real estate and/or maximum weight loading constrains on certain installation locations such as light poles or power lines. Therefore, once an installation site is acquired, it is natural for wireless service providers to use tunable filters to pack many functions, such as multistandards and multibands, into one site. View full abstract»

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  • 38. Transversal Signal Interaction: Overview of High-Performance Wideband Bandpass Filters

    Publication Year: 2014 , Page(s): 84 - 96
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4234 KB) |  | HTML iconHTML  

    This article presents an introduction of recently wideband bandpass filters based on transversal signal interaction concepts. Different resonant structures are reported on, including branch-line coupler/ring resonator, interdigital coupled lines, DSPSL 180° phase-shifting structure, Marchand balun, open/shorted coupled lines, T-shaped structures, and open/shorted stubs. Detailed comparisons of out-of-band transmission zeros, effective circuit size, 3-dB bandwidth, upper stopband, and group delay for the wideband/UWB filters discussed in this article are presented. Different bandwidth of wideband bandpass filters can be realized based on transversal signal interaction concepts, branch-line coupler/ring resonator can be easy to realize wide bandwidth with narrow upper stopbands due to their harmonic response. The filter structures using different 180° phase-shifting structures such as DSPSL, shorted coupled lines, and Marchand balun can meet UWB bandwidth/band demand, and the circuit size can be further reduced, while the selectivity and upper stopband should be further improved. The integrated applications of shorted/open coupled lines and shorted/open stubs can increase the numbers of the transmission zeros out-of-band, besides the circuit size reduction, the upper stopband can be also extended to over 4.7 f0 . Moreover, the transversal signal-interaction concepts have been also extended to the design of differential wideband//UWB balanced bandpass filters with broadband common-mode suppression in our former works. View full abstract»

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  • 39. MIMO systems with antenna selection

    Publication Year: 2004 , Page(s): 46 - 56
    Cited by:  Papers (216)  |  Patents (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1178 KB) |  | HTML iconHTML  

    Multiple-input-multiple-output (MIMO) wireless systems are those that have multiple antenna elements at both the transmitter and receiver. They were first investigated by computer simulations in the 1980s. Since that time, interest in MIMO systems has exploded. They are now being used for third-generation cellular systems (W-CDMA) and are discussed for future high-performance modes of the highly successful IEEE 802.11 standard for wireless local area networks. MIMO-related topics also occupy a considerable part of today's academic communications research. The multiple antennas in MIMO systems can be exploited in two different ways. One is the creation of a highly effective antenna diversity system; the other is the use of the multiple antennas for the transmission of several parallel data streams to increase the capacity of the system. This article presented an overview of MIMO systems with antenna selection. The transmitter, the receiver, or both use only the signals from a subset of the available antennas. This allows considerable reductions in the hardware expense. View full abstract»

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  • 40. RF MEMS phase shifters: design and applications

    Publication Year: 2002 , Page(s): 72 - 81
    Cited by:  Papers (83)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (9860 KB) |  | HTML iconHTML  

    Recent results obtained with MEMS phase shifters demonstrate that their performance is much better than GaAs phase shifters using either standard (switched-line, reflect-line) or distributed designs. The reliability of MEMS phase shifters is worse than of single switches since they employ 8-16 MEMS switches and do not tolerate a failure in any of the switches. On the other hand, a large phased array will still function properly, albeit with a slightly decreased efficiency and higher sidelobes if 3-4% of the phase shifters fail. Currently, the failure mechanisms of MEMS switches are being investigated and will greatly benefit the reliability of MEMS phase shifters. Also, the hermetic packaging of MEMS phase shifters is not straightforward, due to their relatively large size. It is for these reasons that the authors believe that MEMS phase shifters will be mostly used in satellite and defense applications in the next five years View full abstract»

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  • 41. Statistical Multiband Multistandard LNA Module

    Publication Year: 2015 , Page(s): 111 - 115
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1795 KB)  

    In recent years, wireless and mobile communications systems, such as Global System for Mobile Communications, wideband code-division multiple access, wireless local area networks, long-term evolution, and Bluetooth, have been developed for concurrent operation in a single mobile device. Therefore, a multiband multistandard low-noise amplifier (LNA) is required to provide low noise figure (NF), high gain, and high linearity over a wide frequency range. View full abstract»

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  • 42. The last barrier: on-chip antennas

    Publication Year: 2013 , Page(s): 79 - 91
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3752 KB) |  | HTML iconHTML  

    This paper has presented a comprehensive overview of on-chip antennas, which remain the last bottleneck for achieving true SoC RF solutions. CMOS remains the mainstream IC technology choice but is not well suited for on-chip antennas, requiring the use of innovative design techniques to overcome its shortcomings. Codesign of circuits and antennas provide leverage to the designer to achieve optimum performance. The layout of on-chip antennas is dictated by foundry specific rules whereas characterization of on-chip antennas requires special text fixtures. For future highly integrated SoC solutions, foundries will have to provide special layers for efficient on-chip antenna implementations, as they currently do for on-chip inductors. In many of the emerging applications such as THz communication, implantable systems and energy harvesting, on-chip antennas have shown immense potential and are likely to play a major role in shaping up future communication systems. View full abstract»

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  • 43. High efficiency class-F RF/microwave power amplifiers

    Publication Year: 2006 , Page(s): 40 - 48
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1698 KB) |  | HTML iconHTML  

    This article provides a tutorial and review of recent developments in high-efficiency class F RF/ microwave PAs. The principles of class-F RF PAs are explained first. Recent progress in their theory and in design techniques is then presented. Different approaches of class-F PA designs are explained, and some examples of practical designs are illustrated. Finally, an attempt is made to discuss the future developments of class-F RF/microwave PAs. View full abstract»

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  • 44. Flexible Filters: Reconfigurable-Bandwidth Bandpass Planar Filters with Ultralarge Tuning Ratio

    Publication Year: 2014 , Page(s): 43 - 54
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5357 KB)  

    The objective of this overview article is to report the latest research findings in the research into RF/ microwave reconfigurable-bandwidth bandpass planar filters with ultralarge passbandwidth tuning ratio. This means filtering devices with much higher flexibility, showing reconfigurable bandwidths between narrow/moderate-band and ultrawideband states. Specifically, two different solutions we recently proposed are described, with emphasis on their operating principles and achieved electrical performances. They consist of 1) transversal signal-interference switchable-bandwidth bandpass filters and 2) tune-all bandpass filters simultaneously exploiting MMRs and quality-factor control to achieve unprecedented reconfiguration levels in terms of center frequency and instantaneous passbandwidth. Some other modern filtering topologies proposed by other authors, which have clear interest to attain very high levels of bandwidth variation, are also expounded. View full abstract»

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  • 45. Low-Noise Amplifier for Statistical Multiband and Multistandard Applications

    Publication Year: 2015 , Page(s): 116 - 121
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3295 KB)  

    The Low-Noise Amplifier (LNA) Student Design Competition has continuously evolved since its inception. Each year, students have been challenged to design an LNA with an increased emphasis on ruggedness, linearity, and broadband performance [1]-[5]. The 2014 IEEE Microwave Theory and Techniques Society (MTT-S) International Microwave Symposium (IMS2014) continued this trend by requiring students to design an LNA receiver module for statistical multiband and multistandard applications in an effort to raise awareness about the complexity and nondeterministic nature of the topic. For the first time in competition history, the measurement frequencies were not predetermined and were decided on the day of the competition by two rolls of a six-sided die, with each side representing a frequency in gigahertz. This requirement prevented students from optimizing a design for a particular set of frequencies and instead called for a design possessing linear broadband performance from 1 to 6 GHz. View full abstract»

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  • 46. Transmitter Architecture for CA: Carrier Aggregation in LTE-Advanced Systems

    Publication Year: 2013 , Page(s): 78 - 86
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1114 KB) |  | HTML iconHTML  

    CA has already found its place in the deployment of 4G wireless networks. It successfully shows its value as an efficient way to increase the signal bandwidth within the available spectrum. This article is focused on demonstrating and analyzing the possible transmitter architecture solutions for CA. Further, the benefits and issues of using concurrent dual-band transmitter architecture are investigated. The recent progress on deploying concurrent dual-band PAs has been surveyed, where recent published literatures reported significant improvement on the concurrent dual-band PA design and achievable efficiency. The challenges present in the development of the linearization schemes for concurrent dual-band transmitters are addressed and possible solutions are studied. View full abstract»

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  • 47. Ultra-wideband wireless systems

    Publication Year: 2003 , Page(s): 36 - 47
    Cited by:  Papers (355)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2463 KB) |  | HTML iconHTML  

    The recent FCC frequency allocation for UWB has generated a lot of interest in UWB technologies. There is 7,500 MHz of spectrum for unlicensed use. The main limitations are provided by the low-power spectral density and by the fact that the transmit signal must occupy at least 500 MHz at whole times. IEEE 802.15.3a is being developed for high-bit-rate PAN applications, and UWB is the most promising technology to support the stringent requirements: 110, 200, and 480 Mb/s. Two UWB multiband systems, frequency hopping and Spectral Keying, have been described in this article. Both systems meet the stringent requirements provided by IEEE 802.15. View full abstract»

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  • 48. Passing the Plateau of Productivity: Development of RFSOI Technologies on HR Silicon Substrates for Reconfigurable Wireless Solutions

    Publication Year: 2014 , Page(s): S61 - S73
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3823 KB)  

    Products designed with RFSOI on HR silicon for the cellular handset industry are being deployed in large volumes by the leading RF FE providers. These consist of highly integrated RF power switches, RF tuners, and other types of RF circuit blocks. The technologies are available in several different foundries, and the volumes are running in the tens of thousands of wafers per month. The drive for improved linearity needed for LTE 4G systems, in particular CA, will continue to push these technologies to improve their respective figures of merit for continuous leadership in the RF FE. RFSOI on HR silicon is the leading switching technology in handsets today and is poised to continue its dominance for the next decade. View full abstract»

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  • 49. Metamaterial Inspired Microwave Sensors

    Publication Year: 2012 , Page(s): 57 - 68
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2598 KB) |  | HTML iconHTML  

    Cheap and ubiquitous sensor systems will shape the coming decades. There is an emerging class of small high-performance electronic devices such as mobile phones, electronic toys, home appliances, monitoring and control systems in industrial facilities, and medical diagnosis systems, which are or will be equipped with pill box sized microprocessors or computers as well as sensors. These “smart sensors” with limited power and processing capabilities are often wirelessly interconnected. An assembly of many of them spread throughout the physical world will form sensor networks able to identify, localize, and monitor physical, environmental, and industrial processes, biological and health conditions, goods, vehicles, factories, stores, or even people. View full abstract»

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  • 50. Frequency-reconfigurable antennas for multiradio wireless platforms

    Publication Year: 2009 , Page(s): 66 - 83
    Cited by:  Papers (62)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4917 KB) |  | HTML iconHTML  

    Looking to increase the functionality of current wireless platforms and to improve their quality of service, we have explored the merits of using frequency-reconfigurable antennas as an alternative for multiband antennas. Our study included an analysis of various reconfigurable and multiband structures such as patches, wires, and combinations. Switches, such as radio-frequency microelectromechanical systems (RFMEMS) and p-i-n diodes, were also studied and directly incorporated onto antenna structures to successfully form frequency-reconfigurable antennas. View full abstract»

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IEEE Microwave Magazine is intended to serve primarily as a source of information of interest to professionals in the field of microwave theory and techniques.

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Editor-in-Chief
John Wood
Maxim Integrated Products, Inc.

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Phone:+1 480 577 0927