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Microwave Theory and Techniques, IEEE Transactions on

Issue 2 • Date Feb. 2008

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  • Table of contents

    Publication Year: 2008 , Page(s): C1 - C4
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  • IEEE Transactions on Microwave Theory and Techniques publication information

    Publication Year: 2008 , Page(s): C2
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  • Millimeter-Wave-Radar Sensor Based on a Transceiver Array for Automotive Applications

    Publication Year: 2008 , Page(s): 261 - 269
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (917 KB) |  | HTML iconHTML  

    This paper describes a new radar sensor architecture comprising an array of transceiver modules. Target applications of the sensor are automotive driver assistance systems. In conjunction with a monolithic integration of each transceiver, the concept offers the possibility for a cost-effective realization of digital-beamforming radar sensors at millimeter-wave frequencies. A modulation sequence is investigated based on simultaneously transmitted frequency-modulated continuous-wave signals, which are separated by frequency multiplexing. Appropriate signal processing for the estimation of range, speed, and azimuth angle in multiple object situations is presented. Experimental results with an eight-channel radar sensor in the 76-77-GHz frequency band are presented, which demonstrate the feasibility of the proposed architecture and show the performance of the modulation sequence and signal processing. View full abstract»

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  • A Monolithic Phased Array Using 3-bit Distributed RF MEMS Phase Shifters

    Publication Year: 2008 , Page(s): 270 - 277
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1925 KB) |  | HTML iconHTML  

    This paper presents a novel electronically scanning phased-array antenna with 128 switches monolithically implemented using RF microelectromechanical systems (MEMS) technology. The structure, which is designed at 15 GHz, consists of four linearly placed microstrip patch antennas, 3-bit distributed RF MEMS low-loss phase shifters, and a corporate feed network. MEMS switches and high-Q metal-air-metal capacitors are employed as loading elements in the phase shifter. The system is fabricated monolithically using an in-house surface micromachining process on a glass substrate and occupies an area of 6 cm times 5 cm. The measurement results show that the phase shifter can provide nearly 20deg/50deg/95deg phase shifts and their combinations at the expense of 1.5-dB average insertion loss at 15 GHz for eight combinations. It is also shown by measurements that the main beam can be steered to required directions by suitable settings of the RF MEMS phase shifters. View full abstract»

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  • 24-GHz Frequency-Modulation Continuous-Wave Radar Front-End System-on-Substrate

    Publication Year: 2008 , Page(s): 278 - 285
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1049 KB) |  | HTML iconHTML  

    Design and implementation of a 24-GHz frequency-modulation continuous-wave radar front-end system is presented and discussed, and its hybrid planar and waveguide building blocks are fully integrated on one single substrate. A flexible and compact integration methodology on the basis of the substrate-integrated-circuits concept is deployed to design such a microwave front-end system-on-substrate. In this study, it is found that this surface-volume hybrid integration scheme not only enables the complete system integration of planar and nonplanar microwave circuits, but also combines respective advantages of such structures in connection with microstrip lines (planar) and waveguides (nonplanar). Design strategies of the system building blocks including mixers, power dividers, and antenna arrays are discussed together along with the measured results. To verify the developed radar prototype, laboratory-based target-range measurements are conducted. View full abstract»

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  • A Subthreshold Low-Noise Amplifier Optimized for Ultra-Low-Power Applications in the ISM Band

    Publication Year: 2008 , Page(s): 286 - 292
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (647 KB) |  | HTML iconHTML  

    The IEEE 802.15.4 standard relaxes the requirements on the receiver front-end making subthreshold operation a viable solution. The specification is discussed and guidelines are presented for a small area ultra-low-power design. A subthreshold biased low-noise amplifier (LNA) has been designed and fabricated for the 2.4-GHz IEEE 802.15.4 standard using a standard low-cost 0.18-mum RF CMOS process. The single-stage LNA saves on chip area by using only one inductor. The measured gain is more than 20 dB with an S11 of -19 dB while using 630 muA of dc current. The measured noise figure is 5.2 dB. View full abstract»

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  • L- and S-Band Compact Octave Bandwidth 4-bit MMIC Phase Shifters

    Publication Year: 2008 , Page(s): 293 - 299
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1391 KB) |  | HTML iconHTML  

    This paper presents the design approach and test results of L- and S-band compact monolithic microwave integrated circuit (MMIC) phase shifters (PSs) developed for octave band applications. The PS designs were based on an optimum topology selected for each bit for compact size and low insertion loss, and have on-chip integrated digital control. The MMIC PSs were fabricated employing GaAs-based high-performance 0.4-mum MSAG MESFET technology with multilevel-plating process. We achieved a chip size of 2.6 mm2, the smallest size reported to date. View full abstract»

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  • A 2-GHz GaAs HBT RF Pulsewidth Modulator

    Publication Year: 2008 , Page(s): 300 - 304
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (509 KB) |  | HTML iconHTML  

    RF pulsewidth modulation (PWM) has been proposed as an efficiency improving technique for power amplifiers (PAs) handling varying envelope signals. The core idea is to modulate the varying envelope into a square-wave signal such that the width of each pulse is varied according to the envelope, and any phase information is contained in the timing of the pulses. The square wave signal can give a theoretical efficiency of 100% for the subsequent PA. Such a system differs significantly from a conventional up-conversion and PA and, therefore, a significant design challenge results. The first important step is to generate the PWM signal. This paper demonstrates a functional modulator for Universal Mobile Telecommunications System operating at 2 GHz. The modulator is designed in a GaAs HBT process and uses low-frequency feedback combined with predistortion to obtain a high spectral purity. Measurements show a Universal Mobile Telecommunications System PWM signal with more than 10-dB margin to the modulation mask and an error vector magnitude of less than 1.5% rms (requirement: 17.5%). View full abstract»

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  • A Compact Highly Reconfigurable CMOS MMIC Directional Coupler

    Publication Year: 2008 , Page(s): 305 - 319
    Cited by:  Papers (18)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1557 KB) |  | HTML iconHTML  

    This paper presents a tunable CMOS directional coupler that utilizes lumped-element L-C sections. The lumped-element approach used to build the directional coupler makes it possible to integrate the coupler onto a single monolithic microwave integrated circuit (MMIC), as it occupies a small area compared to printed designs. The directional coupler uses varactors and tunable active inductors (TAIs) to synthesize the series and shunt reactances, respectively, which allows extensive electronic control over the coupling coefficient, while insuring a low return loss and a very high isolation. Furthermore, using varactors and TAIs allows the directional coupler to be reconfigured for operation over a wide range of frequencies. Moreover, the symmetric configuration of the coupler allows it to switch from forward to backward operation by simply exchanging the bias voltages applied across the series varactors. The MMIC coupler was fabricated in a standard 0.13-mum CMOS process and operates from a 1.5-V supply. The circuit occupies 730 mum times 600 mum, and is capable of achieving tunable coupling coefficients from 1.4 to 7.1 dB, while maintaining an isolation higher than 41 dB. The MMIC coupler is also capable of operating at any center frequency over the 2.1-3.1-GHz frequency range with higher than 40-dB isolation. The coupler achieves a -4.1-dBm 1-dB compression point while operating from a 1.5-V supply. View full abstract»

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  • Fast Estimation of Spectral Spreading in GSM OPLL Transmitters Based on Folding Effects Analysis in Quadrature Phase Modulator

    Publication Year: 2008 , Page(s): 320 - 327
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (417 KB) |  | HTML iconHTML  

    In a quadrature phase modulator composed of a quadrature mixer and a limiter, spectrum folding effects are analyzed based on the Fourier series of a sinusoidal-carrier pulsewidth-modulated signal. The analysis reveals that the sideband tones after the limiter are created by two different folding mechanisms-dense and sparse folding when the distortion tones are around the odd and even harmonics of the carrier, respectively. The results are then applied to a practical offset phase-locked loop (OPLL) GSM transmitter to identify the origins of critical sideband tones at offset frequencies of 4omegam and 8omegam. A simple static equation is presented to relate the magnitudes of the sideband tones to the spectral spreading of a phase modulated signal. By using the equation, quantitative correlations of the 4omegam and 8omegam sideband tones with the 400-kHz emission level in a Gaussian minimum shift-keying signal are shown. The estimation method is instrumental for performance verification of OPLL transmitters. The analysis results are verified through simulations and measurements. View full abstract»

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  • Analysis of a Fully Matched Saturated Doherty Amplifier With Excellent Efficiency

    Publication Year: 2008 , Page(s): 328 - 338
    Cited by:  Papers (41)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2257 KB) |  | HTML iconHTML  

    A saturated Doherty amplifier based on class-F amplifiers is analyzed in terms of its load modulation behavior, efficiency, and linearity. Simulations included the amplitude ratio and phase difference between the fundamental and third harmonic voltages, the current/voltage waveforms, load lines, and the third-order intermodulation amplitudes/phases of the carrier and peaking amplifiers. The saturated doherty power amplifier was implemented using two Eudyna EGN010MK GaN HEMTs with a 10-W peak envelope power. For a 2.14-GHz forward-fink wideband code-division multiple-access signal, the doherty amplifier delivers an excellent efficiency of 52.4% with an acceptable linearity of -28.3 dBc at an average output power of 36 dBm. Moreover, the amplifier can provide the high linearity performance of -50 dBc using the digital feedback predistortion technique. View full abstract»

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  • 16.6- and 28-GHz Fully Integrated CMOS RF Switches With Improved Body Floating

    Publication Year: 2008 , Page(s): 339 - 345
    Cited by:  Papers (14)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1218 KB) |  | HTML iconHTML  

    This paper presents two fully integrated CMOS transmit/receive (T/R) switches with improved body-floating operations. The first design exploits an improved transistor layout with asymmetric drain-source region, which reduces the drain-source feed-through for body-floated RF switches. In the second design, a switched body-floating technique is proposed, which reconfigures the body-floating condition of a switch transistor in the ON and OFF states. Both designs are fabricated in a standard 0.13-mum triple-well CMOS process. With regard to 2-dB insertion loss, the switch with asymmetric drain-source achieves 28-GHz bandwidth, which is among the highest reported frequencies for CMOS T/R switches. The bandwidth of the switched body-floating design is 16.6 GHz. There is approximately 5 dB better isolation obtained in the switched body-floating design. With the resistive double-well body-floating technique, 26.5- and 25.5-dBm input 1-dB compression point (P1dB) are obtained, respectively. Both designs consume only 150 mum times 100 mum die area. The demonstrated T/R switches are suitable for high-frequency and wideband transceivers. View full abstract»

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  • A Triple-Tuned Ultra-Wideband VCO

    Publication Year: 2008 , Page(s): 346 - 354
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1087 KB) |  | HTML iconHTML  

    We have already proposed a triple-tuned voltage-controlled oscillator (VCO) for achieving an ultra-wideband characteristic. The triple-tuned VCO consists of an active device and three tuned circuits. The fabricated VCO has achieved the oscillation bandwidth of 5.6-16.8 GHz and the phase noise of -114.9 dBc/Hz +/-2.9 dB at 1-MHz offset from the carrier. In this paper, for the first time, the conditions that the VCO achieves the ultra-wideband characteristic are clarified by formulation and simulation. It is also clarified that a transistor of the larger emitter size is suitable for the wideband VCO. In addition, the performances of the proposed VCO are compared with other reported wideband VCOs. As a result, it is shown that the proposed VCO has achieved the lowest figure of merit in the C-Ku-band. View full abstract»

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  • Analysis and Design of a Double-Quadrature CMOS VCO for Subharmonic Mixing at Ka-Band

    Publication Year: 2008 , Page(s): 355 - 363
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1139 KB) |  | HTML iconHTML  

    In this paper, we analyze the potentials of a four-phase 14-GHz CMOS voltage-controlled oscillator, tailored to a sub-harmonic receiver, for signal processing at Ka-band. When mild phase accuracies between in-phase and quadrature down-converted signals are required, the four-phase oscillator displays roughly the same phase noise figure-of-merit as quadrature oscillator counterparts. However, the operation at half-frequency leads to an improved performance due to a higher quality factor of the tuning varactors, and because the local oscillator circuitry and signal path run at different frequencies, relaxing coupling issues. A detailed time-variant analysis of phase noise in multiphase oscillators is introduced and validated by both simulations and experiments. Prototypes realized in a 65-nm technology occupy an active area of 0.5 mm2 and show the following performances: a 26% frequency tuning range (from 12.2 to 15.9 GHz), maximum phase error from pi/4 of 2deg, and a phase noise of -110 dBc/Hz at 1 MHz from 14 GHz, while consuming 18 mA from 0.8-V supply. View full abstract»

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  • Schottky Barrier Diode Circuits in Silicon for Future Millimeter-Wave and Terahertz Applications

    Publication Year: 2008 , Page(s): 364 - 371
    Cited by:  Papers (38)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1244 KB) |  | HTML iconHTML  

    This paper presents Schottky barrier diode circuits fully integrated in a 0.13- mum SiGe BiCMOS process technology. A subharmonically pumped upconverter and a frequency doubler are demonstrated that operate beyond 100 GHz without the need of external components. The upconverter has a size of 430 times 780 mum2 including on-chip matching elements and bond pads. It has a conversion gain of - 6 to - 7 dB from 100 to 120 GHz. The upconverter achieves a high single-sideband saturated output power of - 4 dBm from 100 to 120 GHz and a high linearity with a 1-dB compression point of - 6 dBm. The frequency doubler has a size of 360 times 500 mum2 and can deliver up to 2.5 dBm at 110 GHz. View full abstract»

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  • Multi-Lookup Table FPGA Implementation of an Adaptive Digital Predistorter for Linearizing RF Power Amplifiers With Memory Effects

    Publication Year: 2008 , Page(s): 372 - 384
    Cited by:  Papers (28)  |  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1916 KB) |  | HTML iconHTML  

    This paper presents a hardware implementation of a digital predistorter (DPD) for linearizing RF power amplifiers (PAs) for wideband applications. The proposed predistortion linearizer is based on a nonlinear auto-regressive moving average (NARMA) structure, which can be derived from the NARMA PA behavioral model and then mapped into a set of scalable lookup tables (LUTs). The linearizer takes advantage of its recursive nature to relax the LUT count needed to compensate memory effects in PAs. Experimental support is provided by the implementation of the proposed NARMA DPD in a field-programmable gate-array device to linearize a 170-W peak power PA, validating the recursive DPD NARMA structure for W-CDMA signals and flexible transmission bandwidth scenarios. To the best of the authors' knowledge, it is the first time that a recursive structure is experimentally validated for DPD purposes. In addition to the results on PA efficiency and linearity, this paper addresses many practical implementation issues related to the use of FPGA in DPD applications, giving an original insight on actual prototyping scenarios. Finally, this study discusses the possibility of further enhancing the overall efficiency by degrading the PA operation mode, provided that DPD may be unavoidable due to the impact of memory effects. View full abstract»

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  • A New Wideband Adaptive Digital Predistortion Technique Employing Feedback Linearization

    Publication Year: 2008 , Page(s): 385 - 392
    Cited by:  Papers (33)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1367 KB) |  | HTML iconHTML  

    We develop a new wideband digital feedback predistortion (WDFBPD) technique for modulated signals with wide bandwidths by combining digital feedback predistortion (DFBPD) linearization and memory-effect compensation techniques. For the experiments, a class-AB amplifier using an LDMOSFET with 90-W peak envelope power is employed. The proposed technique is compared with existing DFBPD and memory polynomial (MP) techniques for a 2.14-GHz forward-link WCDMA 2FA signal with 10-MHz carrier spacing. The experimental results show that the new WDFBPD technique has better linearization performance than conventional DFBPD and lower computational complexity than the MP technique. View full abstract»

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  • Phase-Noise Analysis of Injection-Locked Oscillators and Analog Frequency Dividers

    Publication Year: 2008 , Page(s): 393 - 407
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2324 KB) |  | HTML iconHTML  

    In-depth investigation of the phase-noise behavior of injection-locked oscillators and analog frequency dividers is presented. An analytical formulation has been obtained, which allows a better understanding of the shape of the output phase-noise spectrum of these circuits. The simplicity of this formulation is also helpful for circuit design. Approximate expressions for the corner frequencies of the spectrum are determined, identifying the most influential magnitudes and deriving design criteria. In particular, a technique has been developed to shift the frequency of the first corner of the phase-noise spectrum, up to which the output phase noise follows the input one. The expressions for the corner frequencies can be introduced in either in-house or commercial harmonic-balance software, thus allowing an agile design, as no separate phase-noise analysis is required. The validity of the analytical techniques is verified with the conversion-matrix approach and with measurements using two field-effect-transistor-based circuits: a 4.9-GHz injection-locked oscillator and a frequency divider by 2 with 9.8-GHz input frequency. View full abstract»

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  • Efficient Algorithms for Crank–Nicolson-Based Finite-Difference Time-Domain Methods

    Publication Year: 2008 , Page(s): 408 - 413
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (313 KB) |  | HTML iconHTML  

    This paper presents new efficient algorithms for implementing 3-D Crank-Nicolson-based finite-difference time-domain (FDTD) methods. Two recent methods are considered, namely, the Crank-Nicolson direct-splitting (CNDS) and Crank-Nicolson cycle-sweep-uniform (CNCSU) FDTD methods. The algorithms involve update equations whose right-hand sides are much simpler and more concise than the original ones. Analytical proof is provided to show the equivalence of original and present methods. Comparison of their implementations signifies substantial reductions of the floating-point operations count in the new algorithms. Other computational aspects are also optimized, particularly in regard to the for-looping overhead and the memory space requirement. Through numerical simulation and Fourier stability analysis, it is found that while the CNDS FDTD is unconditionally stable, the CNCSU FDTD may actually become unstable. View full abstract»

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  • Exact Equivalent Straight Waveguide Model for Bent and Twisted Waveguides

    Publication Year: 2008 , Page(s): 414 - 419
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (291 KB) |  | HTML iconHTML  

    Exact equivalent straight waveguide representation is given for a waveguide of arbitrary curvature and torsion. No assumptions regarding refractive index contrast, isotropy of materials, or particular morphology in the waveguide cross section are made. This enables rigorous full-vector modeling of in-plane curved or helically wound waveguides with use of available simulators for straight waveguides without the restrictions of the known approximate equivalent-index formulas. View full abstract»

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  • Modeling and Optimization of Compact Microwave Bandpass Filters

    Publication Year: 2008 , Page(s): 420 - 430
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (755 KB) |  | HTML iconHTML  

    This paper presents the modeling and optimization of compact microwave bandpass filters whose compactness leads to complex and strong stray coupling paths, thereby making the identification of a simple and sparse coupling topology difficult and even impossible. The strong coupling coefficients needed for a broadband response can also cause an ambiguity in identifying the spatial extent of local resonances. An equivalent circuit, which is extracted directly from Maxwell's equations, is used in optimizing these filters. The filter is represented by its global resonances instead of individual resonators. The extraction of the parameters of the equivalent circuit is carried out in the physical frequency and not in the normalized frequency in order to preserve the physicality of the equivalent circuit, especially for asymmetric responses. The technique is successfully applied to the optimization of second-order suspended stripline bandpass filters with one transmission zero either below or above the passband, as well as fourth-order filters with three transmission zeros. A fourth-order filter with three transmission zeros is fabricated and measured. View full abstract»

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  • A Compact Open-Loop Filter With Mixed Electric and Magnetic Coupling

    Publication Year: 2008 , Page(s): 431 - 439
    Cited by:  Papers (51)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1039 KB) |  | HTML iconHTML  

    A novel cascaded microstrip open-loop resonator filter with controllable electric and magnetic mixed coupling is presented to have one or more transmission zeros. For two coupled resonators, the coupled sides with the maximum magnetic field are combined with their open gaps with the maximum electric field, creating the electric and magnetic mixed coupling. By adjusting the distances between resonators and the positions of open gaps in a mixed coupled filter, the coupling coefficients can be changed, and controllable transmission zeros can be produced in the lower stopband, upper stopband, or both. Design and fabrication of the proposed second-and fourth-order filters show the advantages: such as a smaller number of resonators, higher rejection level, as well as asymmetrical response; moreover, the location of the transmission zeros can be precisely controlled. View full abstract»

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  • Miniaturized Hexagonal Stepped-Impedance Resonators and Their Applications to Filters

    Publication Year: 2008 , Page(s): 440 - 448
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1623 KB) |  | HTML iconHTML  

    Miniaturized hexagonal stepped-impedance resonators and their applications to bandpass filters are presented. Based on the odd- and even-mode equivalent circuits, the resonance characteristics of these resonators are investigated. A series of circuit configurations, including the third-order Chebyshev, trisection, and fifth-order cascaded trisection filters, are constructed by the proposed resonators. These filters are very compact and have good stopband responses. Measured results validate the analysis and theoretical prediction with good agreement. View full abstract»

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  • RF Amplitude and Phase-Noise Reduction of an Optical Link and an Opto-Electronic Oscillator

    Publication Year: 2008 , Page(s): 449 - 456
    Cited by:  Papers (37)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1949 KB) |  | HTML iconHTML  

    In this paper we examine the optical sources of noise that degrade high-performance microwave photonic links. In particular, we study the residual phase noise due to laser frequency fluctuations and the detector nonlinearity on microwave signals transmitted on an optical fiber, or generated in the opto-electronic oscillator (OEO). Based on experimental findings, we identify a significant reduction of the relative intensity noise of the laser if the received optical power saturates the photodiode. Furthermore, we suggest the use of a semiconductor optical amplifier in saturation as yet another means to reduce the phase noise induced by laser intensity fluctuations. We also identify the use of multiple photodetectors to reduce the influence of associated 1/f noise, which adds to the phase noise of a transmitted microwave signal, and is the ultimate limitation to the phase noise of the high-performance OEO. Reduction of noise that is due to optical interferences is also addressed. View full abstract»

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  • A Series Solution for the Single-Mode Synthesis Problem Based on the Coupled-Mode Theory

    Publication Year: 2008 , Page(s): 457 - 466
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (715 KB) |  | HTML iconHTML  

    In this paper, we present an exact analytical solution for the inverse scattering problem formulated by using the coupled-mode theory in the microwave range, assuming single-mode operation. The solution is a series that gives the required coupling coefficient for the microwave device as a function of the target frequency response. A clear physical meaning for the terms of the series is discussed, and several useful properties for the synthesis are given, thus providing a deep understanding of the synthesis mechanics. The method allows for the design of microwave devices with arbitrary frequency response only constrained by principles of causality, passivity, and stability. The resulting device is, in general, a nonuniform waveguide that features a continuously varying profile, e.g., a nonuniform microstrip line with continuously varying strip width. As an example of the potential of the synthesis method, a matched filter for ultra-wideband applications is finally designed in microstrip technology and successfully tested. View full abstract»

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The IEEE Transactions on Microwave Theory and Techniques focuses on that part of engineering and theory associated with microwave/millimeter-wave components, devices, circuits, and systems involving the generation, modulation, demodulation, control, transmission, and detection of microwave signals. This includes scientific, technical, and industrial, activities. Microwave theory and techniques relates to electromagnetic waves usually in the frequency region between a few MHz and a THz; other spectral regions and wave types are included within the scope of the Society whenever basic microwave theory and techniques can yield useful results. Generally, this occurs in the theory of wave propagation in structures with dimensions comparable to a wavelength, and in the related techniques for analysis and design..

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