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Microwaves, Communications, Antennas and Electronic Systems, 2008. COMCAS 2008. IEEE International Conference on

Date 13-14 May 2008

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Displaying Results 1 - 25 of 69
  • Comparison of three different sub-harmonic mixers implemented in SiGe process technology for the 60GHz license free frequency band

    Publication Year: 2008 , Page(s): 1 - 10
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (897 KB) |  | HTML iconHTML  

    In this paper three sub-harmonic mixers where designed for the 60GHz frequency band using Jazz SBC18hx process. The detailed design of 4th sub-harmonic mixer is presented which is based on the linear abstraction for mixers. A method to extract the ABCD parameters of the mixer from a general purpose harmonic balance simulation results is created. These parameters are used to properly match the mixer. The performance of 2nd sub-harmonic passive mixer with the same topology and that of an active 2nd sub-harmonic Gilbert based mixer are presented. The results of the three mixers are compared. View full abstract»

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  • Moment method solution based on impulse type expansion functions defined in infinite domain

    Publication Year: 2008 , Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1312 KB) |  | HTML iconHTML  

    The well known paired-strips transmission line is solved by the method of moments (MoM) where the expansion functions are defined in infinite domain. The expansion functions obey the physical behavior near the edges of the line and at infinity, and based on impulse functions. We compare our solution to known solution based on conformal mapping and to other efficient MoM solutions, and it is shown that two to four expansion functions are enough for an excellent and fast convergence of the solution. View full abstract»

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  • Towards a micromachined system for mechanical characterization of osteoblasts

    Publication Year: 2008 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (746 KB) |  | HTML iconHTML  

    Measurement of the Young's modulus of bone cells (osteoblasts) is considered to be of paramount importance to investigate and find a more efficient cure for osteoporosis, an illness that is impacting a significant portion of the world's senior population. MEMS technology is an ideal platform to build a better testing system with the desired qualities. Some microdevices based on MEMS technology have been developed for this purpose, but most of them are still in the initial stages of development. In this paper, a BioMEM system for testing the mechanical properties of a biological cell is designed and fabricated which include an electrothermal actuator for the cultured cell compression, a temperature sensor for measuring the temperature in the cell medium, a cell-positioning system and a force sensor for measuring the force applied to the cell. View full abstract»

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  • Recent advances in Vacuum Electronics

    Publication Year: 2008 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1220 KB) |  | HTML iconHTML  

    Vacuum Electronics (VE) technology has been and will continue to be the enabling technology for entire classes of high-power high-frequency amplifiers with the most demanding specifications for use in both military and commercial systems. Here in this paper, TWT design and its application has been described. Among the wide variety of applications requiring high power, communication, radar, EW, and broadcasting systems are all heavily dependent on vacuum devices for reliable performance and high efficiency. Well designed CW klystrons can now deliver more than 10 years of trouble-free service in satellite communication, direct broadcast satellite (DBS) and airport weather radar applications. Such reliability improvements have led to significant reductions in operating cost for many such systems. View full abstract»

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  • Advanced component architectures for detection and communication systems

    Publication Year: 2008 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (369 KB) |  | HTML iconHTML  

    Future military and commercial communication systems and sensors require a new generation of circuits with cognitive, deployable, agile, versatile, survivable and sustainable capabilities. These characteristics can be achieved by systems that are autonomous and have the ability to reconfigure in real-time so they adapt to unexpected changes to the electromagnetic environment or to signals with arbitrary bandwidths. Cognitive matching is a key feature in this architecture. To be able to match in real time and under dynamic operating conditions, the architecture of the matching network has to be designed to provide continuous adaptivity to the incoming signal in order to ensure proper reception and decoding. The requirement to accommodate arbitrary-bandwidth signals, poses significant challenges to traditional time-invariant matching networks because of the gain-bandwidth restrictions and their inability to ensure a linear phase response for broadband pulse-based inputs. To address this need a time-variant matching network architecture that is incorporating high-Q passives is particularly suited for pulse-based systems. View full abstract»

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  • Front-end technology for phased-arrays with digital beamforming

    Publication Year: 2008 , Page(s): 1 - 3
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (32 KB) |  | HTML iconHTML  

    Phased-arrays are widely used in the military and space domain. They are pervading the civil domain in base stations and the like and distribution of systems over a single or multiple platforms is on the way. With increased connectivity and communication between partial systems, it is less problematic to have only partial systems onboard of an individual platform, as the sensor or communication systems will be formed by the co-operating system parts. In this environment, the importance of phased-arrays will increase further, due to the following reasons: (i) arrays offer great advantages in terms of performance; (ii) arrays offer great advantages in mode of degradation; (iii) arrays offer great advantages in flexibility. View full abstract»

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  • Connected phased array antennas for ultra-wide band radar applications

    Publication Year: 2008 , Page(s): 1 - 10
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB) |  | HTML iconHTML  

    The paper presents general properties of arrays of connected slot or dipole antennas providing guidelines for the design of structures. Connected arrays represent one of the most promising array antenna concepts able to meet the very demanding requirements in terms of antenna bandwidth and high polarization purity, imposed by the new generations of radar systems. This array concept can also be applied in other fields like earth based space science or satellite based future missions as well as for wide-band integrated array antennas for telecommunications. View full abstract»

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  • High power nanocrystalline diamond RF MEMS- A combined look at mechanical and microwave properties

    Publication Year: 2008 , Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (910 KB) |  | HTML iconHTML  

    In this paper, a compressively stressed nanocrystalline diamond (NCD) actuator utilizing a thermal actuation scheme is presented. The growth chemistry of NCD films along with the mechanical properties of diamond are discussed in detail. Stress engineering is performed to realize compressively stressed diamond films for RF-MEMS applications. A NCD based bi-stable actuator is designed and fabricated on a low resistive silicon substrate. Tunable switches are implemented in CPW and microstrip topologies and small signal measurements are performed in the frequency range of 5-30 GHz. High power measurements are performed in the power spectrum of 24-47 dBm on the switches integrated in the microstrip topology. View full abstract»

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  • A new circuit topology for LNAs using partial source degeneration with double transistor connection to improve gain and input impedance matching flexibility

    Publication Year: 2008 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (246 KB) |  | HTML iconHTML  

    One of the most important constraints that a designer must face in LNA design is the input impedance matching. The input impedance matching results in optimized gain and noise figure for the amplifier. Considering a single MOS transistor in common-source configuration, a degeneration of the source by an inductance Ls produces a desirable real part on the input impedance. Unfortunately, due to some technology restrains the designer must work with restringed options for Ls values limiting the capability to achieve a desirable impedance. The degeneration also introduces transconductance reduction due to the Ls voltage drop. View full abstract»

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  • Low-cost, panelized digital array radar antennas

    Publication Year: 2008 , Page(s): 1 - 10
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1429 KB) |  | HTML iconHTML  

    The design challenges associated with the development of the antenna array for a highly-integrated, low-cost, panelized radar system have been presented, and the methodology for the development of a digital array radar (DAR) antenna panel has been detailed. Now that a solution for the maximization of scan range in in the DAR antenna panel has been identified, the next step is to integrate real T/R modules into the antenna panel and interface it with a fully-digital backend to ultimately demonstrate the flexibility and capability of this new, low-cost radar system. View full abstract»

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  • Miniature 3D micro-machined solid state power amplifiers

    Publication Year: 2008 , Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1419 KB) |  | HTML iconHTML  

    In this work, a rectangular coaxial transmission line based power amplifier is discussed. This transmission line is created by sequential photolithography and plating processes, resulting in a very wide band, dispersion-less transmission medium which includes integrated passive components. This approach yields a number of advantages over conventional microstrip circuits. This 3D micro-machining technology, called PolystrataTM technology, in which the circuit is the package, and the package is the circuit, enables one other important and far reaching advantage. View full abstract»

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  • Digital RF Processor (DRP™) for wireless transmitters

    Publication Year: 2008 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (177 KB) |  | HTML iconHTML  

    RF transceivers have recently migrated to low-cost digital deep-submicron CMOS processes, where their integration with baseband processors and memory serve to form low cost SoC solutions for various radio standards. Such process environment, optimized for digital logic and SRAM memory, is extremely restrictive for conventional analog and RF designs. This tutorial presents recently developed techniques that transform the RF transceiver circuit design complexities into digital domain, where the strengths of the digital processes are leveraged, allowing the SoC to benefit from simple migration with process node scaling, advanced design automation, re-configurability and testability. Digital signal processing, both hardware and software based, is used extensively to alleviate analog design complexity, allowing the reduction in cost and power consumption in a reconfigurable design environment. This DRPtrade transmitter tutorial focuses on the fundamentals of the digital polar transmitter of the Bluetooth single-chip solution offered by Texas Instruments. View full abstract»

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  • Experimental evidence of surface mobile holes on GaN HEMT structure

    Publication Year: 2008 , Page(s): 1 - 6
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (791 KB) |  | HTML iconHTML  

    In this paper, Hall measurement with an unconventional test vehicle was employed to verify the existence of these surface holes. The result represents a major breakthrough in understanding the effect of polarization induced electron-hole pairs on transistor electrical characteristics and reliability. View full abstract»

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  • Reducing spectral growth of phase coded radar pulses

    Publication Year: 2008 , Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (221 KB) |  | HTML iconHTML  

    A solution to reduce the spectral growth generated from a high rate Bi Phase code modulated radar pulses is presented. The method does not require any amplitude power back off technique that reduces the efficiency of the saturated high power transmitters used for transmitting the radar pulses. This new method of reducing the spectral growth with out affecting the pulse compression performance of the peak side lobe ratio - PSLR, is presented and it was analyzed and tested. View full abstract»

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  • Low profile near field antenna for RFID application

    Publication Year: 2008 , Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB) |  | HTML iconHTML  

    This paper describes a near field reader antenna for UHF RFID applications. The frequency bands used in RFIDare the 900 MHz band and 865 MHz band The first part presents the basic requirements of an RFID system. The paper then presents the special complexities required for a near field application. A new type of antenna is described which meets the special requirements. Simulated results are presented. A full model of the antenna is also shown. The antenna has a low profile .It can be adapted to cover any specified area without adding extra readers. View full abstract»

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  • Analysis of radiation hazards to personnel on marine platforms

    Publication Year: 2008 , Page(s): 1 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (471 KB) |  | HTML iconHTML  

    The large number of radio frequency (RF) transmitters employed in modern marine platforms requires that they operate in mutual coexistence while posing no danger to operators and equipment despite the limited available physical space. A key to the successful system integration is the control of the electromagnetic environment on the shipspsila topsides, which might pose radiation hazards (RADHAZ) to personnel (HERP). HERP are caused by transmitter antenna installations that generate intentional EM radiation in excess of the safe levels in zones of personnel activity. Radiation safety to personnel is achieved when the average radiation power density is below the permissible exposure limits (PEL) for HERP at locations of personnel activity and medical equipment operation. This paper describes the analysis tools and techniques for the evaluation of HERP on marine platforms. The same approaches could be employed in the analysis of land site antenna deployment scenarios. View full abstract»

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  • Phased array — Technology and trends

    Publication Year: 2008 , Page(s): 1 - 8
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (855 KB) |  | HTML iconHTML  

    This paper introduces the requirements of naval radar systems from past to present. It describes phased array technologies (digital and analog) that are presently available in the market. Power sources architectures, A/D evolutions, transceiver architecture and system on chip configurations are described as the main technologies at phased array system. The correlation between the various technologies and phased array architectures trends is also discussed. View full abstract»

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  • Pulsed-IV and RF waveform measurements of unique high-K dielectric GaN MOSFETs

    Publication Year: 2008 , Page(s): 1 - 4
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (729 KB) |  | HTML iconHTML  

    This paper demonstrates the capabilities of a state of the art RF waveform measurement system to explore the RF performance of new compound semiconductor MOSFET devices. Pulsed IV and time domain waveform measurements are presented for recently developed GaN MOSFET devices with high-K epitaxially grown gate dielectrics. The results demonstrate promising performance for first generation devices, with RF power densities above 1 W/mm. The waveform measurements point the way forward for improving future devices by giving direct visual feedback on where performance is being lost. View full abstract»

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  • The purpose-driven network: Optimizing wireless network configurations through value-of-information modeling

    Publication Year: 2008 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (193 KB) |  | HTML iconHTML  

    Military and public safety personnel have reasonably predictable behaviors, which imply predictable communication patterns with arguably separable components. During critical operations, mission-related communications should take priority over all other traffic. Even within this category there exist classes of traffic (e.g., situational awareness, command and control) that have distinctive patterns of localization and information reuse, depending on an organizationpsilas operational processes. Modeling and simulation (M&S) is useful in determining sources, sinks and criticalities by breaking and retarding selected information streams and examining the impact on downstream decisions and organizational responses. The results of such analysis can provide the framework and constraints for determining which network configurations optimize the value of traffic for a host of missions. View full abstract»

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  • Novel paper-based inkjet-printed antennas and wireless sensor modules

    Publication Year: 2008 , Page(s): 1 - 8
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (944 KB) |  | HTML iconHTML  

    In this paper, inkjet-printed flexible antennas fabricated on paper substrates are introduced as a system-level solution for ultra-low-cost mass production of UHF radio frequency identification (RFID) tags and wireless sensor nodes (WSN) in an approach that could be easily extended to other microwave and wireless applications. The presented material is a review of our grouppsilas major reported milestones in this area. First, we discuss the benefits of using paper as a substrate for high-frequency applications, reporting its very good electrical/dielectric performance up to at least 1 GHz. The RF characteristics of the paper-based substrate are studied by using the microstrip ring resonator in order to characterize the dielectric properties (dielectric constant and loss tangent). Then, we give details about the inkjet printing technology, including the characterization of the conductive ink, which consists of nano-silver-particles, while highlighting the importance of this technology as a fast and simple fabrication technique especially on flexible organic (e.g. LCP) or paper-based substrates. A compact inkjet-printed UHF ldquopassive-RFIDrdquo antenna using the classic T-match approach and designed to match ICpsilas complex impedance, is presented as a demonstrating prototype for this technology. In addition, the author briefly touches up the state-of-the-art area of fully-integrated wireless sensor modules on paper and show the first ever 2D sensor integration with an RFID tag module on paper, as well as the possibility of a 3D multilayer paper-based RF/microwave structures. The presented approach could potentially set the foundation for the development of low-cost light-weight autonomous nodes for cognitive intelligence applications and for wearable communication and biomonitoring systems. View full abstract»

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  • Receiver protection considerations for T/R modules employed in AESA systems

    Publication Year: 2008 , Page(s): 1 - 4
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (131 KB) |  | HTML iconHTML  

    Modern AESA (active electronically scanned array) phased-array RADAR systems are composed of thousands of T/R (transmit/receive) modules which directly dominate both the performance and the cost of the RADAR system. Therefore, the major task for the T/R module designer is to comply with these challenging requirements. One of the major design issues associated with the front-end architecture of the T/R module is the implementation of the receiver protection circuitry (limiter) which insures both the reliability as well as the proper functionality of the module. All receiver protection considerations must also be linked to the other front-end elements, in particular, the HPA (high power amplifier), the antenna and the receiver chain. View full abstract»

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  • Optical stepper based 150mm GaAs PHEMT for microwave and millimeter-wave MMIC applications

    Publication Year: 2008 , Page(s): 1 - 6
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (399 KB) |  | HTML iconHTML  

    The gate geometry of PHEMT determines the upper limit in microwave and millimeter-wave frequencies at which the transistor can be optimally useful as amplifiers. In addition to production of 0.5 mum and 0.15 mum feature gate length PHEMT on 150 mm GaAs wafer substrate, WIN has recently developed the 0.25 mum variety targeting mmic solutions covering from below X-band to frequency as high as 60 GHz. This presentation reports on device amplification performance achieved by various gate length from 0.5 mum to 0.25 mum that are created with optical I-line stepper based photolithography. AT 10 GHz, both the 0.5 mum and 0.25 mum devices achieved 60% power-added efficiency while the later is able to provide higher output power of 900 mW/mm at 7 volt operation. This report also looks at how the higher fabrication throughput, stepper-based device approaches RF performance of the 0.15 mum device made with electron-beam based lithography. Our stepper-based device has a lower capacitance CGD than our E-beam based 0.15 mum device due to optimization of gate formation. This provides a higher gain upto 60 GHz inspite of its slightly lower unity current gain cutoff frequency FT, which is a result of the longer gate length. Leveraging the high gain available, it is possible to realize multi-function millimeter-wave MMIC with this stepper-base technology where the PHEMT needs to have good performance in gain, RF output power, and efficiency; and it also needs to have good low noise characteristics for LNA circuit, and low on resistance and high isolation when working as a switching device. From characterization data, we are showing here that this can be simultaneously achieved. Additionally, in order to aid versatility in circuit design, both the depletion-mode device and the enhancement mode device are fabricated. This will enable low supply power consumption, and the integration of logic and control circuits in the monolithic multi-function chip. View full abstract»

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  • Distributed power delivery model construction by analytical approximations

    Publication Year: 2008 , Page(s): 1 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (780 KB) |  | HTML iconHTML  

    The paper provides closed set of analytical approximation flows, that allow extremely fast derivation of platform structures distributed electrical models. The simulation results exhibit similar behavior as those produced by more accurate electro-magnetic extraction flows. View full abstract»

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  • Inter-pulse coding for ideal range response

    Publication Year: 2008 , Page(s): 1 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1343 KB) |  | HTML iconHTML  

    A different way to increase the energy within a coherent processing interval (CPI) is suggested - many short dense pulses with inter-pulse coding instead of few widely-spaced long pulses with intra-pulse coding. Long coded pulses result in masking targets at close range and suffer from poor Doppler tolerance. We overcome the range ambiguity, inherent to dense pulses (high PRF), by inter-pulse coding. Ideal range response (no ambiguity, no sidelobes) can be obtained, e.g., by using a binary periodic Ipatov sequence for inter-pulse coding. The periodic property is maintained as long as the number of transmitted periods exceeds the number of processed periods by at least two. View full abstract»

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  • Analysis of radiation from a line source in a grounded dielectric slab covered by a metal strip grating

    Publication Year: 2008 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (257 KB) |  | HTML iconHTML  

    A metal strip grating over a grounded dielectric slab (MSG-GDS) is a well studied canonical structure with many applications to antennas. Although many studies on the dispersion characteristics of the MSG-GDS can be found in the literature, not much work can be found on the excitation of this structure by a localized source. It is therefore our aim to investigate the later. To this end we solve the 2D problem with a line source excitation. View full abstract»

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