By Topic

Popular Articles (October 2014)

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

    Page(s): 108 - 120
    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

    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

    Page(s): 59 - 71
    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

    Page(s): 34 - 50
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3109 KB)  

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

    Page(s): 97 - 109
    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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  • 6. Progress for Behavioral Challenges: A Summary of Time-domain Behavioral Modeling of RF and Microwave Subsystems

    Page(s): 91 - 105
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3236 KB)  

    The quest for the best compromise between the requirements for battery preservation and system operation linearity in the radio frequency (RF) and microwave front end has been a constant push for research on behavioral modeling of active devices since the early days of satellite communications [1] and has accelerated with the growth of modern mobile communication infrastructures. This focus has resulted today in a vast amount of behavioral model options, especially for the RF power amplifier (PA), in which it is not always simple for a designer to find his or her way as discussed in [2]-[5]. Using the term "behavioral model," we define these models as those derived from the observation of the electrical variables at the block ports (with very little insight on the internal composition of the block) and dedicated to the modeling of baseband/bandpass subsystems. Unlike transistor-level compact modeling, where there are well-established initiatives for model standardization driven by foundries and computer-aided design vendor companies [6], [7], there is, unfortunately, no such comparable effort yet at the subsystem level [8]. This article offers a concise summary of the recent progress on time-domain behavioral modeling with a particular focus on the continuous-time (CT) modeling theory [9]. View full abstract»

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  • 7. Predictable Behavior: Behavioral Modeling from Measured Data

    Page(s): 75 - 90
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2667 KB)  

    This article presents an overview of the rapidly growing field of microwave devices? behavioral modeling, serving as an introductory overview to the two feature articles that follow it. Beginning with the distinction between behavioral and physics-based modeling, it provides an introduction to the under-lying theory of microwave device behavioral modeling, paving the way to the formulation of the most often used time-domain and frequency-domain model formats, whose details and applications are then explored in the other two articles of this special issue. Because behavioral modeling is, in its essence, a compact and systematic way of recording measured data and, from that, predicting similar behaviors, this article finally reviews the specific microwave measurement instruments necessary to extract the model parameters and validate the adopted model. View full abstract»

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  • 8. Quick Switch: Strongly Correlated Electronic Phase Transition Systems for Cutting-Edge Microwave Devices

    Page(s): 32 - 44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2352 KB)  

    The authors discuss an overview of strongly correlated electron systems and metal-insulator transition (MIT) oxide materials. Microwave applications of MIT materials are also introduced. This overview offers a vision for future microwave devices with adaptive capabilities. View full abstract»

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

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

    Page(s): 70 - 82
    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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  • 11. Substrate Integrated Waveguide Filter: Basic Design Rules and Fundamental Structure Features

    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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  • 12. MIMO systems with antenna selection

    Page(s): 46 - 56
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1178 KB)  

    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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  • 13. Power without wires

    Page(s): S64 - S73
    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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  • 14. Flexible Filters: Reconfigurable-Bandwidth Bandpass Planar Filters with Ultralarge Tuning Ratio

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

    Page(s): 39 - 56
    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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  • 16. Transversal Signal Interaction: Overview of High-Performance Wideband Bandpass Filters

    Page(s): 84 - 96
    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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  • 17. The Sound the Air Makes: High-Performance Tunable Filters Based on Air-Cavity Resonators

    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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  • 18. Stretching the Design: Extending Analytical Circuit Design from the Linear to the Nonlinear Domain

    Page(s): 106 - 120
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4514 KB)  

    In the design of most electronic circuits and systems, designers use computer-aided design (CAD) tools to guide the design flow. They exploit the ability of CAD tools to perform algebraic operations to compute/ predict circuit and system performance. This is possible because, in most electronic circuits and systems, linear operation can be assumed. The behavior of microwave components, circuits, and systems can, for example, be described in terms of "behavioral" parameters, such as Z-parameters, Y-parameters, and S-parameters. Transformation from one parameter to another is achieved by simple linear algebraic operations [1]. The performance of more complex circuits can be computed via linear matrix operations using the relevant parameters, i.e., Y-parameters for parallel connections and Z-parameters for series connections. More significantly, performance predictions can also be obtained via linear algebra transformations, i.e., the maximum gain, minimum noise figure, potential instability, etc., along with design insight, i.e., gain circles, noise circles, optimum input/output match requirements, and so on [1], [2]. View full abstract»

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  • 19. RF MEMS phase shifters: design and applications

    Page(s): 72 - 81
    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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  • 20. 60 GHz Wireless: Up Close and Personal

    Page(s): 44 - 50
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2816 KB)  

    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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  • 21. Implantable RF Medical Devices: The Benefits of High-Speed Communication and Much Greater Communication Distances in Biomedical Applications

    Page(s): 64 - 73
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2692 KB) |  | HTML iconHTML  

    In the early ages of implantable devices, radio frequency (RF) technologies were not commonplace due to the challenges stemming from the inherent nature of biological tissue boundaries. As technology improved and our understanding matured, the benefit of RF in biomedical applications surpassed the implementation challenges and is thus becoming more widespread. The fundamental challenge is due to the significant electromagnetic (EM) effects of the body at high frequencies. The EM absorption and impedance boundaries of biological tissue result in significant reduction of power and signal integrity for transcutaneous propagation of RF fields. Furthermore, the dielectric properties of the body tissue surrounding the implant must be accounted for in the design of its RF components, such as antennas and inductors, and the tissue is often heterogeneous and the properties are highly variable. Additional challenges for implantable applications include the need for miniaturization, power minimization, and often accounting for a conductive casing due to biocompatibility and hermeticity requirements [1]?[3]. Today, wireless technologies are essentially a must have in most electrical implants due to the need to communicate with the device and even transfer usable energy to the implant [4], [5]. Low-frequency wireless technologies face fewer challenges in this implantable setting than its higher frequency, or RF, counterpart, but are limited to much lower communication speeds and typically have a very limited operating distance. The benefits of high-speed communication and much greater communication distances in biomedical applications have spawned numerous wireless standards committees, and the U.S. Federal Communications Commission (FCC) has allocated numerous frequency bands for medical telemetry as well as those to specifically target implantable applications. The development of analytical models, advanced EM simulation software, and representative RF human phantom recipes h- s significantly facilitated design and optimization of RF components for implantable applications. View full abstract»

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  • 22. Handheld Computers: Smartphone-Centric Wireless Applications

    Page(s): 36 - 44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2370 KB) |  | HTML iconHTML  

    A smartphone is a mobile phone built on a mobile operating system with more advanced computing capability and connectivity than regular or conventional cell phones have [1]. Driven by increasing demands, they have become more popular in our daily life; there are already more than 1.08 billion smartphones around the world [2] and smartphone sales continues to grow. According to a press release by Gartner Inc., worldwide smartphone sales to end users reached 225 million units in the second quarter of 2013 and, for the first time, smartphones account for the majority of global cellphone shipments [3]. In particular, smartphones with Google's Android mobile operating system and Apple's iOS hold more than 93% of the market share [3]. View full abstract»

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  • 23. Mitigate the Interference: Nonlinear Frequency Selective Ferrite Devices

    Page(s): 45 - 56
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4116 KB)  

    The linear "small-signal" properties of ferrites gave rise to several well-known microwave devices [1], [2], such as circulators, isolators, phase shifters, tunable oscillators, and tunable filters, that have had a significant impact on microwave systems following their first synthesis by Snoek [3], [4] in 1945. However, ferrites also show useful nonlinear "large-signal" properties that have been applied in power-limiter and power-enhancer devices. While these devices have not seen widespread application, their unique frequency-selective signal attenuation properties offer potential solutions to current and anticipated radiofrequency (RF) interference problems resulting from ever-increasing signal density and demands on scarce RF bandwidth. View full abstract»

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  • 24. Atom Magnetism: Ferrite Circulators—Past, Present, and Future

    Page(s): 66 - 72
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1585 KB)  

    Magnetism, at the very fundamental level, is attributed to the circular motion of elementary charges. This occurs when electrons spin around their own axes or when they rotate around the nucleus of an atom. The combination of these two types of motion gives an atom its magnetic moment [1]. The three most significant elements from the point of view of magnetism are iron, nickel, and cobalt. Their atoms possess a large magnetic moment due to a large number of unpaired electrons in their outermost shell. They also naturally assume a crystal structure with all atoms aligned with their magnetic moments in the same direction, a configuration referred to as "ferromagnetism" [2]. View full abstract»

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  • 25. The last barrier: on-chip antennas

    Page(s): 79 - 91
    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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  • 26. Space solar power programs and microwave wireless power transmission technology

    Page(s): 46 - 57
    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. History of GaN: High-Power RF Gallium Nitride (GaN) from Infancy to Manufacturable Process and Beyond

    Page(s): 82 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4000 KB) |  | HTML iconHTML  

    In the early 1990s, gallium nitride (GaN) was deemed an excellent, next generation, semiconductor material for high power/high frequency transistors based on the material parameters of bandgap, electron mobility, and saturated electron velocity. The lack of bulk GaN source material led to the need for GaN growth on mismatched substrates such as Si, SiC and sapphire, but fundamental material development controlled the pace of maturation of GaN technology for both electronic and optoelectronic applications. The development of GaN for RF electronics was significantly aided by the intense development that occurred in the race to first production of blue and, eventually, white light-emitting diodes (LEDs). Ultimately, advancements in the growth of device-grade aluminum gallium nitride (AlGaN)/GaN heterostructures culminated in the demonstration of record power density RF amplifiers. View full abstract»

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

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

    Page(s): 78 - 86
    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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  • 30. The Sky's the Limit: Key Technology and Market Trends in Satellite Communications

    Page(s): 65 - 78
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    The growth of demand for broadband has been seen in satellite communications as it has in other aspects of the market. Satellites carry media content around the globe, which includes satellite television, radio, and broadband services directly to consumers. Satellite communications also allows for mobile or nomadic voice and data globally. They are also critical to disaster recovery and emergency preparedness, providing critical communications following natural disasters. While the sole application of some satellites is the distribution of data, all satellites require communication systems technology. For example, remote sensing satellites may be collecting environmental data, but the data collected and the command and control of the satellite both rely on communication technology. If large amounts of data is being collected, broadband data links are required to avoid loss of data since on-board storage capacity for this data is limited. View full abstract»

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  • 31. Tuned to Resonance: Transfer-Function-Adaptive Filters in Evanescent-Mode Cavity-Resonator Technology

    Page(s): 55 - 69
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    A number of promising technologies can be found today in the marketplace of reconfigurable filter ideas. They range from sub-mm-scale acoustic filters, lumped elements, two-dimensional resonators, and full three-dimensional solutions. From a system perspective, an equally diverse pool of communication, radar, electronic warfare, and sensing systems need reconfigurable filters. Despite a strong demand for such filters though, it is not easy to identify a technology that satisfies all requirements. While it is relatively straightforward to satisfy one or two important specifications such as low loss or high selectivity, it is often quite challenging to simultaneously satisfy all of them. For instance, this is particularly true when low power consumption, small form factor, and low loss become simultaneously critical decision factors. Several combinations of such factors can result in necessary design tradeoffs with no obvious solutions. Table 1 summarizes several common deciding factors in selecting a reconfigurable filter technology. View full abstract»

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  • 32. Modeling RF MEMS Devices

    Page(s): 83 - 110
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2759 KB) |  | HTML iconHTML  

    The term radio frequency (RF) microelectromechanical systems (MEMS) refers to electronic devices with a moving submillimeter-sized part (beam, comb, disc, or ring), which provide RF functionality. Alternative definitions include bulk or surface micromachined devices, such as thin film bulk acoustic resonators (FBARs), which rely on energy transduction from the electrical energy domain to the acoustic energy domain and vice versa to provide RF functionality. Many introductory articles and textbooks have been written on MEMS and RF MEMS. This article focuses on electrostatically actuated RF MEMS devices, such as RF MEMS switches, switched capacitors and varactors, and vibrating RF MEMS resonators. View full abstract»

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

    Page(s): 109 - 114
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    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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  • 34. Modeling GaN: Powerful but Challenging

    Page(s): 82 - 96
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    As GaN technology has developed, first in research laboratories and more recently in multiple commercial device manufacturers, the demand for improved nonlinear models has grown alongside the device process improvements. The need for improved models for GaN is twofold: first, GaN devices have unique nuances in behavior to be addressed; second, there is a desire for improved accuracy to take full advantage of the performance wins to be gained by GaN HEMT performance in the areas of high efficiency and high-power operation. View full abstract»

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  • 35. Terahertz Terabit Wireless Communication

    Page(s): 108 - 116
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    Recently, terahertz (THz) technology has attracted a great deal of interest from academia and industry. This is due to a number of interesting features of THz waves, including the tens and hundreds of gigahertz bandwidths available, and the fact that this frequency band poses only a minor health threat. Also, as millimeter-wave communication systems mature, the focus of research is, naturally, moving to the THz range. According to Shannon theory, the broad bandwidth of the THz frequency bands can be used for terabit-per-second (Tb/s) wireless indoor communication systems (see "Terabit Versus Terahertz"). This enables several new applications, such as cordless phones with 360° auto stereoscopic displays, optic-fiber replacement, and wireless Tb/s file transferring. All of these applications provide higher quality and a better user experience. Although THz technology could satisfy the demand for an extremely high data rate, a number of technical challenges need to be overcome or better understood before its development. This article provides an overview the state-of the-art in THz wireless communication and it is also a tutorial for an emerging application in Terabit radio systems. The objective is to construct robust, low-cost wireless systems for THz terabit communications. View full abstract»

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  • 36. Solving the Spectrum Crisis: Intelligent, Reconfigurable Microwave Transmitter Amplifiers for Cognitive Radar

    Page(s): 94 - 107
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    In 2009, the U.S. Federal Communications Commission (FCC) chair, Julius Genachowski, warned of a looming spectrum crisis [1]. Issues such as a 2010 saga involving satellite communications interfering with the global positioning system (GPS)have reminded us that spectrum is becoming an ever-precious commodity. With wireless broadband technologies evolving at a rate that will outgrow the available spectrum, the U.S. government has acted to try to "stop the bleeding." President Barack Obama's National Broadband Plan of 2010 [2] mandates that 500-MHz of spectrum be reallocated for wireless broadband applications. However, the continued surge in wireless spectrum users shows that even this spectrum will be used quickly and that a new paradigm is needed. Many have suggested that dynamic spectrum access (DSA), where spectrum is assigned in real time, will be the sharing protocol of the future, and that future spectrum users will be required to be frequency-flexible and cognitive. Radar systems are spectrum users that, in their present form, will have difficulty operating in this future environment because of their fixed operating frequencies, high power, and tendency to leak power into neighboring bands and interfere with other users. In 2011, National Telecommunications and Information Administration (NTIA) Chief of Staff Thomas Power stated, "The community and policy makers must begin to understand the challenges and constraints that currently exist for radar" [3]. The last three years have witnessed an upshot of radar spectrum conferences and meetings, many organized by the NTIA and the Department of Defense's (DoD's) Joint Spectrum Center. Our interest has been stimulated through encountering this issue in military radars, and in participating as speakers and panelist in many of these meetings, including a 2011 NTIA meeting for radar and communications experts to converse about coexistence challenges. However, the DoD, the FCC, and the NTIA still have not developed- any technically sound solutions to achieve spectrum sharing between radar and communications. Wireless broadband expansion is not going away. The cry to radar operators is clear: radar systems must change how they operate. View full abstract»

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  • 37. Tuning in to RF MEMS

    Page(s): 55 - 72
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6851 KB)  

    RF MEMS technology was initially developed as a replacement for GaAs HEMT switches and p-i-n diodes for low-loss switching networks and X-band to mm-wave phase shifters. However, we have found that its very low loss properties (high device Q), its simple microwave circuit model and zero power consumption, its high power (voltage/current) handling capabilities, and its very low distortion properties, all make it the ideal tuning device for reconfigurable filters, antennas and impedance matching networks. In fact, reconfigurable networks are currently being funded at the same level-if not higher-than RF MEMS phase shifters, and in our opinion, are much more challenging for high-Q designs. View full abstract»

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  • 38. Metamaterial Inspired Microwave Sensors

    Page(s): 57 - 68
    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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  • 39. Understanding Leaky-Wave Structures: A Special Form of Guided-Wave Structure

    Page(s): 87 - 96
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2095 KB) |  | HTML iconHTML  

    Guided-wave structures are the foundation for the design and development of RF and microwave circuits and systems. Whether it is planar or nonplanar, periodic or straight, a guided-wave structure, which consists of metallic and/or dielectric composite building blocks, is used to support signal propagation and processing. Except for free-space propagation, diffraction and scattering in an open medium or space, microwave energy is usually transferred by means of specially designed guided-wave structures with modal propagation behavior that are fundamentally characterized by a propagation constant and transmission loss with respect to specific guided-wave modes. Those modes are structure and frequency dependent, and satisfy the boundary conditions of a guided-wave structure. Guided-wave structures can be divided into two kinds, open and closed. The completely closed structures are known to support only the wave guided therein, while the open structure, including semi-open or partially open structures, are subject to a potential gradual wave leakage along the propagation path. Wave leakage is always related to wave guidance, which is very much dependent on a number of factors including structural geometry, fill materials, operating frequency and guided mode. Such leakage can be used positively to develop a leaky-wave structure called a leaky-wave antenna, which enjoys some distinctive properties such as beam-scanning with frequency. Leaky-wave radiating structures are easily fabricated at millimeter wave frequencies compared with other antennas. Although leaky-wave and guided-wave structures have similar characteristics and can be designed by common methods, the simulation and design of leaky-wave structures are usually much more complicated. This is because leaky-wave structures are not closed and their attenuation constant related to leakage needs to be considered. In this article, we focus on the presentation of basic operating principles and special features of pos- tive leaky-wave structures (leaky-wave antennas) ranging from straight to periodic geometries. View full abstract»

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  • 40. Quantum Sensitivity: Superconducting Quantum Interference Filter-Based Microwave Receivers

    Page(s): 57 - 65
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    Several critical applications of superconducting electronics that have been successfully commercialized are the Josephson voltage standard, superconducting quantum interference device (SQUID) magnetometers, superconductor-insulator-superconductor (SIS) mixers, and analog filters. More recently, digital and mixed-signal circuits based on rapid single flux quantum (RSFQ) logic have also made an impression on the high-speed/high-frequency electronics application markets. View full abstract»

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  • 41. Linear and Efficient Doherty PA Revisited

    Page(s): 73 - 79
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1487 KB) |  | HTML iconHTML  

    Designing a simultaneously linear and efficient radio-frequency (RF) power amplifier (PA) is no simple task. The Microwave Theory and Techniques Technical Committee on The High Power Amplifier Components (MTT-5), aiming to promote this challenge at the student level, organized the ninth version of its annual high efficiency PA contest at the 2013 IEEE Microwave Theory and Techniques Society (MTT-S) International Microwave Symposium (IMS2013). Built upon our participation in 2012, the 3.5-GHz linear Doherty PA design was only slightly modified in response to a change in the gain requirement of this year's competition rules. View full abstract»

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  • 42. Faster than fiber: The future of multi-G/s wireless

    Page(s): 104 - 112
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1876 KB) |  | HTML iconHTML  

    This article provides an introduction to a panel session at the 2009 International Microwave Symposium (IMS 2009) on enabling multi-gigabit per second (Gb/s) wireless communication links. Blasting beams of high-speed data through free space is not new. Terahertz spectrum near visible light has been used for ultrahigh-speed optical links for many years. Newly released millimeter-wave (mm-wave) bands provide a similar potential but with different operating characteristics. Advances in manufacturing are yielding high-reliability, high-frequency mm-wave devices, faster digital field programmable gate arrays (FPGA) processors, and superfast analog-to-digital (A/D) and digital-to-analog (D/A) converters that enable higher frequency transceivers, faster modems, and more cost-effective radio architectures that need to be reliably realized. This panel session will explore the technologies being developed within the industry to enable this new field of communications. The strengths and weakness of each technology will be debated, and the viability of each to provide a compelling alternative to fiber will be determined. The panel will bring together leading device engineers with system providers to provide a complete overview of the state-of-the-art Gb/s communications and a road map for the future. View full abstract»

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  • 43. Easy-to-Swallow Wireless Telemetry

    Page(s): 90 - 101
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1424 KB) |  | HTML iconHTML  

    Many countries will experience the effects of an aging population, resulting in a high demand of healthcare facilities. Development of novel biomedical technologies is an urgent necessity to improve diagnostic services for this demographic. Electrocar diogram (ECG) and temperature recording have been used for more than 50 years in medical diagnosis to understand various biological activities [1], [2]. A more recent development, electronic pill technology, requires the integration of more complex systems on the same platform when compared to conventional implantable systems. A small miniaturized electronic pill can reach areas such as the small intestine and can deliver real time video images wirelessly to an external console. Figure 1 shows an electronic pill system (i.e., wireless endoscopy) for a medical monitoring system. The device travels through the digestive system to collect image data and transfers the data to a nearby computer for display with a distance of one meter or more. A high resolution videobased capsule endoscope produces a large amount of data, which can then be delivered over a high-capacity wireless link. View full abstract»

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  • 44. Push the Envelope: Design Concepts for Envelope-Tracking Power Amplifiers

    Page(s): 68 - 81
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    As mobile communication systems evolve to handle higher data rates, their modulation schemes only become more complicated, generating signals with large bandwidth and high peak-to-average-power ratio (PAPR). To amplify such signals with high efficiency, the power amplifier (PA) should have high efficiency not only at the peak power level but also at low power, especially over the maximum power generation region. To realize these PA characteristics, the drain bias voltage of the transistor can be modulated on the basis of the input envelope power to minimize the dc supply power. Thus, the drain bias voltage should follow the envelope of the modulated signal, and this is called envelope tracking (ET). Usually, the envelope is shaped to realize the optimum performance from the ET PA. The PA is biased close to class B, and the dc current is automatically adjusted to the power level. The resulting PA has high efficiency for all power levels, comparable to the maximum efficiency of the PA at high power. In practice, the efficiency is degraded somewhat at low voltage because of the knee effect, lower transconductance, and mismatch effect for different drain bias voltages. View full abstract»

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  • 45. Mach-Zehnder: A Review of Bias Control Techniques for Mach-Zehnder Modulators in Photonic Analog Links

    Page(s): 102 - 107
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2016 KB) |  | HTML iconHTML  

    The Mach-Zehnder modulator (MZM) has been widely used for broadband photonic analog links and high-speed digital optical fiber communication systems because it possesses large modulation bandwidth, low driving voltage, and low chirp. The MZM is a very important optical modulator for photonic applications. In an MZM, the input light is split into two paths, each of which is modulated by an electrical signal. Then the two arms are combined to generate an intensity-modulated light or a phase-modulated light at the output of the MZM. An MZM can be made of lithium niobate (LiNbO3), gallium arsenide (GaAs), or indium phosphide (InP), materials that exhibit some anisotropy in their dielectric properties. Theoretically, the relation of output optical field and driving voltage is a cosine function, i.e., nonlinear transfer function. For RF photonics, the MZM has typically two applications: optical harmonic generation for optical frequency multiplication and optical subcarrier modulation for optical signal modulation. For optical frequency multiplication, high transfer-function nonlinearity is preferred. In contrast, high transfer-function linearity is preferred for optical subcarrier modulation. It is well known that a cosine transfer function can present high or low nonlinearity dependent on operation voltage. Specifically, bias voltages determine the degree of nonlinearity or linearity of the MZM transfer function. For optical frequency multiplication such as millimeter-wave generation, the MZM should be biased at some specific bias points, such as minimum transmission, maximum transmission, and quadrature bias points, to enhance nonlinearity [1]?[2]. For optical subcarrier modulation, biasing an MZM in its linear region such as quadrature bias points allows transmitting broadband RF signals with multioctave bandwidth and improves spurious free dynamic range (SFDR). Therefore, care must be taken to maintain and control the MZM bias point for a specific applicat- on. View full abstract»

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  • 46. Q-Band Millimeter-Wave Antennas: An Enabling Technology for MultiGigabit Wireless Backhaul

    Page(s): 121 - 130
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2363 KB) |  | HTML iconHTML  

    The bandwidth demands in mobile communication systems are growing exponentially day by day as the number of users has increased drastically over the last five years. This mobile data explosion, together with the fixed service limitations, requires a new approach to support this increase in bandwidth demand. Solutions based on lower-frequency microwave wireless systems may be able to meet the bandwidth demand in a short term. However, with the small-cell mass deployment requiring total capacities of 1 Gb/s/km2, scalable, multigigabit backhaul systems are required. Millimeter-wave technology fits nicely into these new backhaul scenarios as it provides extended bandwidth for high-capacity links and adaptive throughput rate, which allows efficient and flexible deployment. Besides these advantages, millimeter-wave solutions become even more attractive when the cost of backhaul solutions and the cost of spectrum licenses are factored in. Compared to the cost of laying fiber to a cell base station, which is the only other scalable solution, the millimeter-wave solution becomes the most appropriate approach. View full abstract»

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  • 47. No Battery Required: Perpetual RFID-Enabled Wireless Sensors for Cognitive Intelligence Applications

    Page(s): 66 - 77
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    Over the last decade, radio frequency identification (RFID) systems have been increasingly used for identification and object tracking due to their low-power, low-cost wireless features. In addition, the explosive demand for ubiquitous rugged low-power, compact wireless sensors for Internet-of-Things, ambient intelligence, and biomonitoring/ quality-of-life application has sparked a plethora of research efforts to integrate sensors with an RFID-enabled platform. The rapid evolution of large-area electronics printing technologies (e.g., ink-jet printing and gravure printing) has enhanced the development of low-cost RFID-enabled sensors as well as accelerated their large-scale deployment. This article presents a brief overview of the recent progress in the area of RFID-based sensor systems and especially the state-of-the-art RFID-enabled wireless sensor tags realized through the use of ink-jet printing technology. View full abstract»

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  • 48. Passive millimeter wave imaging

    Page(s): 39 - 50
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    This article introduces the concept of passive millimeter-wave (PMMW) imaging, describes the phenomenology that defines its performance, explains the technology advances that have made these systems a reality, and presents some of the missions in which these sensors can be used. View full abstract»

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  • 49. Graphene for Microwaves

    Page(s): 81 - 86
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    Graphene nanoelectronics is an emerging area of research. The 2010 Nobel Prize for physics was awarded to A. Geim and K. Novoselov for the discovery of graphene and its unexpected physical properties, paving the way for many new applications in the area of nanoelectronics, nanooptics, and solid state physics. The most-studied microwave device is the graphene transistor, which, in only three years, has reached a cutoff frequency of 100 GHz. As consequence of this impressive development, the prediction that a 0.5-1 THz graphene FET transistor will soon be demonstrated is quite realistic. Moreover, graphene multipliers and other microwave graphene devices are expected to follow the graphene FET development dynamics and reach 100 GHz in few years. View full abstract»

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  • 50. Ultra-wideband wireless systems

    Page(s): 36 - 47
    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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Aims & Scope

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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Meet Our Editors

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

San Jose, CA      USA
john.wood@ieee.org
Phone:+1 480 577 0927