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Microwave Theory and Techniques, IEEE Transactions on

Issue 9 • Date Sept. 2011

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Displaying Results 1 - 25 of 33
  • Table of contents

    Publication Year: 2011 , Page(s): C1 - C4
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  • IEEE Transactions on Microwave Theory and Techniques publication information

    Publication Year: 2011 , Page(s): C2
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  • Temporal Pulse Compression Beyond the Fourier Transform Limit

    Publication Year: 2011 , Page(s): 2173 - 2179
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (572 KB) |  | HTML iconHTML  

    It is a generally known that the Fourier transform limit forbids a function and its Fourier transform to both be sharply localized. Thus, this limit sets a lower bound to the degree to which a band-limited pulse can be temporally compressed. However, seemingly counterintuitive waveforms have been theoretically discovered, which, across finite time intervals, vary faster than their highest frequency components. While these so-called superoscillatory waveforms are very difficult to synthesize due to their high amplitude sidebands and high sensitivity, they open up the possibility toward arbitrarily compressing a temporal pulse, without hindrances from bandwidth limitations. In this paper, we report the design and realization of a class of superoscillatory electromagnetic waveforms for which the sideband amplitudes, and hence, the sensitivity can be regulated. We adapt Schelkunoff's method for superdirectivity to design such temporally compressed superoscillatory pulses, which we ultimately realize in an experiment, achieving pulse compression 47% improved beyond the Fourier transform limit. View full abstract»

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  • Understanding Anomalous Extraordinary Transmission From Equivalent Circuit and Grounded Slab Concepts

    Publication Year: 2011 , Page(s): 2180 - 2188
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (970 KB) |  | HTML iconHTML  

    In this paper, we perform an analysis of anomalous extraordinary transmission (ET) through hole arrays in a rectangular lattice. This phenomenon is a peak of high or even total transmission when the polarization is parallel to the short periodicity of the hole array, and it only happens when the perforated plate is backed by a dielectric slab. The analysis is done using equivalent circuit concepts, and the performance is evaluated for several combinations of dielectric slabs on both faces. Two types of anomalous ET are shown, depending on the dielectric slab parameters. The phenomenon is also analyzed in terms of grounded slab diffraction modes and following the transversal resonance method as an open cavity resonance. Finally, an extension to rectangular waveguides is done, recognizing the similarities, but also emphasizing the intrinsic differences, related with the different modal distribution in the free-space and waveguide models. These results can help to fully understand anomalous ET with simple circuit concepts and to deepen the physical understanding of the problem by observing the same phenomenon from different points of view. Applications in filters, both in free-space and waveguide architectures, as well as in microscopy, are foreseen. View full abstract»

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  • Analysis of Dispersion and Losses in Helically Corrugated Metallic Waveguides by 2-D Vector Finite-Element Method

    Publication Year: 2011 , Page(s): 2189 - 2196
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB) |  | HTML iconHTML  

    Hollow metallic circular waveguides with helical corrugation of the inner surface (helical waveguides) attract considerable interest for various applications such as interaction regions in gyrotron traveling-wave tubes and as a dispersive medium for passive microwave pulse compression. In this paper, we employ a vector finite-element method in 2-D formulation for computation of the dispersion, attenuation characteristics, and the distribution of electromagnetic fields of eigenwaves of helical waveguides. As shown by comparison with the results of previously performed 3-D calculations, the presented method provides sufficient accuracy of calculating the characteristics of helical waveguides for a number of practically important cases at much lesser consumption of computer resources. View full abstract»

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  • Efficient and Systematic Solution of Real and Complex Eigenvalue Problems Employing Simplex Chain Vertices Searching Procedure

    Publication Year: 2011 , Page(s): 2197 - 2205
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (696 KB) |  | HTML iconHTML  

    This paper presents a novel method that is very efficient in solving multidimensional real and complex eigenvalue problems, commonly employed in electromagnetic analysis, which can be transformed into a nonlinear equation. The concept is realized as root tracing process of a real or complex function of N variables in the constrained space. We assume that the roots of the continuous function of N variables lie on the continuous (N-1) -dimensional hyperplane. The method uses regular N and (N-1)-Simplexes, at which vertices the considered function changes its sign. Based on (N-1)-Simplex, the function is evaluated at two new points that are vertices of new regular N-Simplexes for which (N-1)-Simplex is one of its (N-1)-faces. The algorithm, with the usage of stack, runs in an iterative mode tracing the roots inside the volume of the considered simplexes. As a result, the algorithm creates a chain of simplexes in the constrained region. The proposed algorithm is optimal in the sense of the number of function evaluations. The numerical results, real and complex dispersion characteristics of chosen microwave guides, have proven the versatility and efficiency of the proposed algorithm. View full abstract»

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  • Improved Design of Single-Section and Cascaded Planar Directional Filters

    Publication Year: 2011 , Page(s): 2206 - 2213
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB) |  | HTML iconHTML  

    An improved analysis and design of single-section and cascaded planar directional filters is addressed, based on approximate and exact microwave circuit analyses, and the resulting characteristics of matching, coupling, band elimination, and isolation are investigated. The effects of finite even-mode reactance and the unavoidable loss of capacitively coupled parallel branch are also studied. It is known that better performance of single-section directional filters, especially in matching, can be gained by compensating the line length between coupling resonators. It is confirmed that cascading identical directional filters introduces transmission zeros in the stopband, allowing sharper cutoff characteristics. Furthermore, a flatter passband, as well as improved band elimination, are observed. It is also shown that the introduced transmission zeros can be controlled properly by adjusting the connecting-line lengths between directional filters or the parameters related to the coupling resonator. For an efficient design with better performance, accurate design equations are provided with graphs. As a validation check, a microstrip directional filter was designed with a fractional bandwidth of 2.5% at 2.5 GHz and transmission zeros of 2.40 and 2.61 GHz. Good agreement between the measurement and design specifications shows the validity of the proposed configuration, related analysis, and design theory. View full abstract»

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  • Compact Second-Order Highly Linear Varactor-Tuned Dual-Mode Filters With Constant Bandwidth

    Publication Year: 2011 , Page(s): 2214 - 2220
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB) |  | HTML iconHTML  

    This paper presents a compact highly linear tunable second-order quasi-elliptic filter with constant 3-dB bandwidth. The proposed filter is thoroughly analyzed to clearly describe the filter equivalent circuit and the tuning mechanism involved. In addition, the tunable resonator configuration employed is shown to improve filter linearity, especially for low bias voltages where distortion is normally stronger. A quasi-elliptic tunable filter was designed, built, and tested for illustration and verification. With a 3-dB bandwidth variation of only 4.6%, the filter had a frequency coverage from 1.45 to 1.96 GHz, an insertion loss better than 2.5 dB, and measured IIP3 >; 43 dBm throughout. The experimental results are in excellent agreement to theory and simulations. View full abstract»

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  • Novel Design Method of Tri-Band Power Divider

    Publication Year: 2011 , Page(s): 2221 - 2226
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (793 KB) |  | HTML iconHTML  

    A novel method is presented for the design of a multiband power divider. The method employs network theory and even-odd-mode analysis to derive the equivalent input and output port admittances of a three-port junction, which is based on the conditions of reciprocity, isolation, and matching. If an impedance transformer that transforms the equivalent admittance to normalized unit conductance at multiple frequencies is found, then the multiband power divider can be constructed by attaching the transformer to each port of the junction. To verify the proposed design method, three different tri-band power dividers are designed and simulated, of which one is fabricated and measured. The measured results are in good agreement with the simulations. The return loss and isolation are better than 15 dB, simultaneously, the measured bandwidths of three operating bands are over 100 MHz, and the passband ripple is 0.2 dB. View full abstract»

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  • A Compact Dual-Band 90° Coupler With Coupled-Line Sections

    Publication Year: 2011 , Page(s): 2227 - 2232
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1145 KB) |  | HTML iconHTML  

    A new dual-band 90° coupler using coupled transmission lines is proposed in this paper. As the coupler consists of only three quarter-wave coupled-line sections, it occupies less circuit area as compared to other existing dual-band branch-line couplers. A desired dual-band operation can be achieved by proper design of the coupling level for those coupled-line sections. Moreover, the coupler's configuration contains a degree of freedom so that its design is “customizable,” allowing itself to be conveniently realized on a variety of circuit and substrate technologies. As a result, it is suitable for use in many practical applications. View full abstract»

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  • A Miniaturized and Broadband Balun Using Artificial Coupled Line With Imaginary Even-Mode Impedance

    Publication Year: 2011 , Page(s): 2233 - 2240
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (846 KB) |  | HTML iconHTML  

    A broadband and miniaturized balun is proposed using the artificial coupled line with the imaginary even-mode impedance. The artificial coupled line is a metamaterial transmission line with zero electrical length for the even-mode excitation, whereas it behaves like a TEM transmission line with approximately constant characteristic impedance for the odd-mode excitation. Based on the artificial coupled line, a new concept to design a broadband balun is presented. The broadband characteristic of the balun is explained by the odd- and even-mode analysis. A balun is realized using low-temperature co-fired ceramic fabrication technology, simulated by a full-wave tool, and measured in the three-port vector network analyzer system. It exhibits good amplitude imbalance of 0.3 dB and phase imbalance of 179°±3° with the return loss greater than 10 dB from 3.3 to 7.1 GHz with 73% of fractional bandwidth. Its electrical size is only 0.063×0.44λ g2 and its physical size is 1.6×11.2 mm2. Compared with previous works, the proposed balun possessing good balance has a more compact size with broadband operation. View full abstract»

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  • Design of a Mutual Coupling Compensation Network for a Small Receiving Monopole Array

    Publication Year: 2011 , Page(s): 2241 - 2245
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (997 KB) |  | HTML iconHTML  

    The design of a new mutual coupling compensation network for a small and compact-size receiving monopole array is presented. This is the first example for the experimental realization of mutual coupling compensation in a receiving array by using the receiving mutual impedances. The compensation network is designed on a printed circuit board substrate using only passive circuit components to minimize the additional circuit noise. Its output voltages are carefully measured and verified to satisfy the requirements. Its compensation function is experimentally demonstrated with a two-element monopole array in a directional-of-arrival estimation example using the MUSIC algorithm. The experimental results confirm the effectiveness and accuracy of using the receiving mutual impedances in mutual coupling analysis. View full abstract»

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  • A Consistent Charge Model of GaAs MESFETs for Ku -Band Power Amplifiers

    Publication Year: 2011 , Page(s): 2246 - 2253
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (604 KB) |  | HTML iconHTML  

    In this paper, a consistent gate charge model for GaAs MESFETs based upon charge conservation is proposed for monolithic microwave integrated circuit power amplifier designs. This new model is capable of accurately modeling the transistor under various biasing conditions. The conventional approaches for charge modeling of GaAs MESFETs usually adopt analytical equations to fit nonlinear gate capacitors separately, which might be difficult to implement in circuit simulators whose capacitance is always the derivative of an internal state variable (charge). Moreover, compared with the conventional diode and Statz model, the performance prediction in the linear region, saturation knee region, and subthreshold region is greatly improved. Measured and modeled results of a 2 ×150 μm GaAs MESFET are compared and good agreement has been obtained. Comparisons between the proposed model, diode junction model, and Statz model are also presented in this paper. In addition, a class-AB Ku-band power amplifier using a 0.18-μm GaAs MESFET process was designed with the new model for verification of the new model accuracy. View full abstract»

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  • A 6-bit Fully Binary Digital-to-Analog Converter in 0.25- \mu{\hbox {m}} SiGe BiCMOS for Optical Communications

    Publication Year: 2011 , Page(s): 2254 - 2264
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1780 KB) |  | HTML iconHTML  

    This paper presents an approach to implement a high-speed binary weighted digital-to-analog converter (DAC). A different current switching mechanism is proposed that improves the dynamic performance of binary weighted DACs. Circuit simulation shows an improvement of the rise (fall) time mismatch by a factor of 2 over the conventional structure. It is shown that in a conventional high-speed binary DAC implemented with differential pairs, the spurious-free dynamic range (SFDR) can be degraded by nearly 6 dB due to the different rise (fall) times of the current switches. Using the proposed current switches, a fully binary weighted DAC with nominal resolution of 6 bit has been fabricated in 0.25-μm SiGe technology. The measured SFDR is higher than 30.1 dBc up to 5.9-GHz input signal with a 13.4-GHz clock. The DAC can provide 1.1-V peak-to-peak differential output swing over 50 Ω while dissipating 1050 mW. Full-scale 20%-80% fall time and 2% settling time are measured below 18 and 45 ps, respectively. View full abstract»

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  • A Novel Frequency Control Loop for Tunable Notch Filters

    Publication Year: 2011 , Page(s): 2265 - 2274
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1226 KB) |  | HTML iconHTML  

    In this paper, a novel frequency control loop system for tunable notch filters is presented. The frequency control loop is designed for automatically tuning a microelectromechancial systems tunable notch filter, which has 22-dB rejection in the notch band and less than 0.8-dB insertion loss over a 5-MHz passband bandwidth in the International Mobile Telecommunications band (2.1 GHz). The filter frequency control loop is based on sensing the reflection phase change of a reference signal (in this case, the transmitter carrier) and is developed to track the transmitter operation frequency. View full abstract»

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  • 1.58-GHz Third-Order CMOS Active Bandpass Filter With Improved Passband Flatness

    Publication Year: 2011 , Page(s): 2275 - 2284
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1030 KB) |  | HTML iconHTML  

    This paper presents a third-order active bandpass filter (BPF), realized in an area of 0.58% λ0 by 0.44% λ0 at 1.58 GHz (not including contact pads and λ0 is the free-space wavelength at 1.58 GHz) using standard 0.18-μm CMOS one-poly six-metal technology. A survey of the literature shows that a prototype of such a BPF has the lowest normalized area per resonator of active BPFs. The synthetic transmission line, which is used in the active BPF herein, enables the prototype to be substantially miniaturized. Moreover, this paper describes a modified composite cross-coupled nMOS resonator that can equalize passband ripples. A comparison between the measured and simulated data verifies the third-order filter response with 8% 3-dB bandwidth at 1.58 GHz. The insertion loss is 0.68 dB at the central frequency with a passband ripple of 1.24 dB and the active BPF consumes 8 mA from a 1.8-V supply. View full abstract»

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  • Design of Wideband LNAs Using Parallel-to-Series Resonant Matching Network Between Common-Gate and Common-Source Stages

    Publication Year: 2011 , Page(s): 2285 - 2294
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1602 KB) |  | HTML iconHTML  

    A method is proposed to design wideband low-noise amplifiers (LNAs) made of cascaded common-gate (CG) and common-source (CS) stages with a parallel-to-series resonant interstage matching network. The first CG stage has a dual-band response, and the second CS stage has higher gain between these two bands. By applying the proposed interstage matching technique, conjugate matching is achieved at high and low bands, while the midband loss is compensated by the second stage. The output network of the first stage and the input network of the second stage resonate at the same frequency. Two wideband LNAs are designed based on this method and implemented in 0.18- μm RF-mixed signal CMOS process. The first LNA operates at 3.1-10.3 GHz, having 9.6-12.71 dB of power gain and 2.5-3.9 dB of noise figure (NF) at the power consumption of 13.4 mW. The second LNA operates at 14.3-29.3 GHz, having 8.25 ± 1.65 dB of power gain and 4.3-5.8 dB of NF at the power consumption of 13.9 mW. View full abstract»

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  • Increasing Doherty Amplifier Average Efficiency Exploiting Device Knee Voltage Behavior

    Publication Year: 2011 , Page(s): 2295 - 2305
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1104 KB) |  | HTML iconHTML  

    This contribution presents the theoretical analysis and design guidelines to increase the average efficiency of a Doherty power amplifier (DPA), accounting for the device on-resistance. Starting from a simplified device model, closed-form equations for the estimation of both design parameters and obtainable performances are reported. Moreover, advantages and disadvantages of the approach are deeply investigated through a comparison with the standard implementation of a DPA, i.e., based on constant knee voltage behavior. Finally, as experimental support for the developed theoretical analysis, two X-band monolithic microwave integrated circuit DPAs, based on the same GaAs technology, have been designed, realized, and tested. The first one was based on the standard methodology, while the other one has been optimized exploiting the device knee voltage behavior. Measurement results validated the developed analysis, confirming what is theoretically expected for the main DPA features. In particular, both DPAs have 29 dBm of output power with 7.2 dB of power gain in 6 dB of output power back-off (OBO). The efficiency is larger than 35% for the standard DPA and 42% for the one designed exploiting the device on-resistance, in the same OBO region. View full abstract»

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  • A 2.5-V Low-Reference-Voltage 2.8-V Low- Collector–Voltage Operation 0.8–0.9-GHz Broadband CDMA BiFET Power Amplifier With an Input SPDT Band Select Switch

    Publication Year: 2011 , Page(s): 2306 - 2317
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1144 KB) |  | HTML iconHTML  

    This paper describes circuit design and measurement results of a bipolar field-effect transistor monolithic microwave integrated circuit power amplifier (PA) module operating with a 2.5-V low reference voltage (Vref) and a 2.8-V low collector supply voltage (Vcc). While covering 824-925-MHz broadband CDMA operation at 2.8 V of Vcc, the PA allows a 1.1-V low Vcc and 18-dBm output power (Pout) operation. This is realized using an on-chip step quiescent current control scheme depending on Vcc. In addition, an input high electron-mobility transistor single-pole double-throw switch is integrated on the PA die for selecting 800/900-MHz operating bands, thereby providing easy connectivity between a transmit surface acoustic wave filter and the PA. Measurement results under the 2.8/1.1-V Vcc and 2.5-V Vref bias conditions show that the PA meets J-CDMA/W-CDMA power and distortion specifications sufficiently over a wide temperature range from -20 °C to 85 °C while realizing a broadband operation ranging from 824 to 925 MHz. For J-CDMA (IS-95B) modulation, the PA can deliver a 28-dBm Pout, a 36% power-added efficiency (PAE), and a - 50-dBc adjacent channel power ratio, while a 29-dBm Pout, a 38% PAE, and a -40-dBc adjacent channel leakage power ratio (ACLR) are achieved for W-CDMA (3GPP R99) modulation. Under 3:1 load mismatching condition, the PA also suppresses ACLR of less than - 36 dBc while keeping a forward power of 27.5 dBm. Moreover the PA is capable of delivering a 18-dBm Pout and more than 26% PAE under 824-925-MHz and 1.1-V J-CDMA modulation test conditions. To the best of authors' knowledge, this is the first report on a broadband production-level CDMA PA operating with low Vref and low Vcc. View full abstract»

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  • A 16-kV HBM RF ESD Protection Codesign for a 1-mW CMOS Direct Conversion Receiver Operating in the 2.4-GHz ISM Band

    Publication Year: 2011 , Page(s): 2318 - 2330
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1434 KB) |  | HTML iconHTML  

    A decreasing-sized π -model electrostatic discharge (ESD) protection structure is presented and applied to protect against ESD stresses at the RF input pad of an ultra-low power CMOS front-end operating in the 2.4-GHz industrial-scientific-medical band. The proposed ESD protection structure is composed of a pair of ESD devices located near the RF pad, another pair close to the core circuit, and a high-quality integrated inductor connecting these two pairs. This structure can sustain a human body-model ESD level higher than 16 kV and a machine-model ESD level higher than 1 kV without degrading the RF performance of the front-end. A combined on-wafer transmission line pulse and RF test methodology for RF circuits is also presented confirming previous results. The front-end implements a zero-IF receiver. It has been implemented in a standard 2P6M 0.18-μm CMOS process. It exhibits a voltage gain of 24 dB and a single-sideband noise figure of 8.4 dB, which make it suitable for most of the 2.4-GHz wireless short-range communication transceivers. The power consumption is only 1.06 mW from a 1.2-V voltage supply. View full abstract»

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  • Accuracy Criterion for S -Matrix Reconstruction Transforms on Multiport Networks

    Publication Year: 2011 , Page(s): 2331 - 2339
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1013 KB) |  | HTML iconHTML  

    S-matrix reconstruction transforms are based on two stages of matrix transformation to remove the mismatch-induced errors. Over the years, these transforms are widely used in measurements of multiport devices using a two-port vector network analyzer, especially for noncoaxial applications because high-quality matched loads are hardly accessible. In this paper, analytical error analysis of the S-matrix reconstruction transforms is performed to develop the accuracy criterion that is explicitly expressed in matrix form in terms of the S-matrix of the multiport device and the reflection coefficient matrix of the auxiliary terminations. The analytical insights in this paper can pave the way for using strongly reflecting auxiliary terminations. For noncoaxial measurements, strongly reflecting termination, such as a short-circuited or an open-circuited transmission line is more repeatable, reliable, and economical than terminations with loss like resistors. Consequently, the use of strongly reflecting auxiliary terminations is speculated to ease noncoaxial multiport measurements. View full abstract»

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  • All-Optical Microwave Photonic Filter Based on Electrooptic Phase Modulator and Detuned Wavelength Division De-Multiplexer

    Publication Year: 2011 , Page(s): 2340 - 2349
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (677 KB) |  | HTML iconHTML  

    We theoretically and experimentally investigate a microwave photonic filter with an electrooptic phase modulator and an array waveguide grating, which acts as a detuned two-channel wavelength division de-multiplexer. In the experiment, a microwave notch filter with a QN factor of 236 and a rejection ratio of 31 dB is obtained by introducing microwave subtraction directly in optical domain. The parameter QN factor is defined to measure the rejection selectivity of a microwave notch filter and corresponding to the Q factor in a microwave bandpass filter. A microwave bandpass filter with a Q factor of 245 and a rejection ratio of 38 dB is also obtained. The relationship between the Q factor of the microwave bandpass filter and the QN factor of the microwave notch filter is measured. The variations of Q and QN versus the detuning of the tunable optical bandpass filter (TOBF), which is incorporated in the recirculating delay line loop, is also measured and discussed. Simulation results about the influences of the wavelength division de-multiplexer and TOBF on the microwave frequency response are also presented and analyzed. View full abstract»

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  • Tunable Carrier Generation and Broadband Data Upconversion for RoF Systems Based on Stimulated Brillouin Scattering

    Publication Year: 2011 , Page(s): 2350 - 2356
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (860 KB) |  | HTML iconHTML  

    We present a frequency-tunable RF carrier generation and broadband data upconversion technique for radio-over-fiber (RoF) systems. A dual-parallel Mach-Zehnder modulator is used to realize single-mode modulation (SMM). On the other hand, frequency-tunable RF carrier generation with single-sideband (SSB) modulation is performed using stimulated Brillouin scattering (SBS) with three types of configuration. The optical carrier-to-sideband ratio of the SMM-SSB modulated signal can be adjusted to achieve the best received sensitivity performance of the RoF system by simply modifying the pump power in the SBS process. Finally, the transmission performance of the RoF downlink system is examined. The power penalty is less than 1 dB at the bit-error rate of 10-9 after 25-km single-mode fiber transmission. View full abstract»

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  • Analysis of the Signal Response of a Scanning-Beam Millimeter-Wave Correlation Radiometer

    Publication Year: 2011 , Page(s): 2357 - 2368
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1641 KB) |  | HTML iconHTML  

    An analysis of the response of a scanning-beam millimeter-wave correlation radiometer is presented with an emphasis on the spectral signal response. The derivation and subsequent analysis presented here focuses specifically on the effects of the natural oscillation of the signal, called the fringe frequency, as it pertains to rotating sensors. The amplitude and bandwidth of the spectral density are analyzed in multiple cases, including for tracking and nontracking antennas, and for situations in which the antenna beam or the fringe washing function of the correlation radiometer is wide and can be neglected. Closed-form solutions are found for the case where the antennas track the source. Theoretical and simulated responses are given, and experimental results are compared to expected results from the theory for a correlation radiometer designed for security sensing. Measured experimental results show minimal deviation from theoretical calculations, validating the theoretical models derived herein. View full abstract»

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  • Corrections to “A Two-Channel 8–20-GHz SiGe BiCMOS Receiver With Selectable IFs for Multibeam Phased-Array Digital Beamforming Applications” [Mar 11 716-726]

    Publication Year: 2011 , Page(s): 2369
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (54 KB)  

    In the above titled paper (ibid., vol. 59, no. 3, pp. 716-726, Mar. 2011), "EVM" is used as an acronym for both "evanescent-mode" and "error vector magnitude" causing confusion. Clarification of the text is presented here. 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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