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Microwave and Wireless Components Letters, IEEE

Issue 5 • Date May 2008

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Displaying Results 1 - 25 of 33
  • Table of contents

    Page(s): C1 - C4
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  • IEEE Microwave and Wireless Components Letters publication information

    Page(s): C2
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  • Envelope LOD Wave Equation PML Algorithm for Dispersive Band-Limited FDTD Applications

    Page(s): 293 - 295
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (220 KB) |  | HTML iconHTML  

    Unconditionally stable envelope scalar wave equation perfectly matched layer algorithm is presented for truncating dispersive finite difference time domain (FDTD) grids. The algorithm is based on the locally one dimensional FDTD formulations and it is suitable for band-limited electromagnetic applications. Two-dimensional numerical examples are included to show the validity of the proposed formulations. View full abstract»

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  • ADI-FDTD Method With Fourth Order Accuracy in Time

    Page(s): 296 - 298
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (139 KB) |  | HTML iconHTML  

    This letter presents an unconditionally stable alternating direction implicit finite-difference time-domain (ADI-FDTD) method with fourth order accuracy in time. Analytical proof of unconditional stability and detailed analysis of numerical dispersion are presented. Compared to second order ADI-FDTD and six-steps SS-FDTD, the fourth order ADI-FDTD generally achieves lower phase velocity error for sufficiently fine mesh. Using finer mesh gridding also reduces the phase velocity error floor, which dictates the accuracy limit due to spatial discretization errors when the time step size is reduced further. View full abstract»

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  • Minimizing Electromagnetic Scattering by Varying Height of Metallic Surfaces

    Page(s): 299 - 301
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (142 KB) |  | HTML iconHTML  

    This letter determines the dimensional profile of a periodic metallic surface that minimizes the electromagnetic energy scattering of an incident plane-wave back in the incident direction, irrespective of the plane-wave incidence angle. Simple Fourier series is used to describe the surface height variation and it is shown that a small number of design parameters are required to obtain the optimal profile of the surface. Experimental validations are presented and a very good agreement with electromagnetic simulation results is achieved. View full abstract»

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  • New Reference Function for Post-Processing Uncertainty Evaluation in SAR Compliance Tests

    Page(s): 302 - 304
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (383 KB) |  | HTML iconHTML  

    A reference function for the post-processing uncertainty evaluation in specific absorption rate (SAR) compliance tests is proposed. The new reference function, derived from real SAR distributions measured during compliance sessions of handsets, is characterised by a double Gaussian distribution with asymmetrical standard deviation parameters, in each half space. Standard deviation parameters as well as SAR penetration are frequency dependent data. The proposed reference function also takes into account SAR distributions with two (or more) local maxima. The analysis for the derivation of the reference function parameters based on GSM900, DCS1800, UMTS and IEEE 802.11b measured SAR distributions is presented as well as details on uncertainty computations. A generalization of the method is presented too. View full abstract»

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  • Frozen Modes in Coupled Microstrip Lines Printed on Ferromagnetic Substrates

    Page(s): 305 - 307
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB) |  | HTML iconHTML  

    A microstrip transmission line model is proposed for magnetic photonic crystals having a stationary inflection point in their dispersion diagrams. The model is formed from an existing degenerate band edge microstrip circuit by replacing the substrate material with a properly biased ferrite. Using the four port unit cell's transfer matrix, we calculate the dispersion diagram of the periodic structure and verify the stationary inflection behavior. Variation of the geometry parameters to tune the k - omega diagram is also discussed. View full abstract»

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  • Realization and Experimental Verification of Chiral Cascaded Circuit

    Page(s): 308 - 310
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (348 KB) |  | HTML iconHTML  

    In this letter, we present an implementation for the previously proposed chiral cascaded circuit (CCC) using lumped capacitors, inductors, and transformers. The design of a 180/0deg four-port coupler with one-unit-cell CCC is then presented. Both simulation and experimental results show that such a coupler with identical load at four ports behaves as an analogue to an isotropic chiral slab residing in a simple isotropic medium. Thus we indirectly verify the chiral characteristic of CCC using experiments. View full abstract»

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  • An In-Line Waveguide-to-Microstrip Transition Using Radial-Shaped Probe

    Page(s): 311 - 313
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (533 KB) |  | HTML iconHTML  

    In this letter, an in-line waveguide-to-microstrip transition at Ka-band is presented. It utilizes a radial-shaped probe a quarter-wavelength away from the waveguide short-back, which is also used as a support for the microstrip substrate, to terminate the TE10 mode of the standard waveguide. This printed structure is easy to fabricate and convenient to be installed in the waveguide cavity with a split-block configuration. A test module at Ka-band is designed and fabricated. It provides a return loss better than 10 dB from 26.5 to 38.5 GHz and an insertion loss of 1.2 to 2 dB within a wide frequency range from 26.5 to 36.2 GHz with a low cost, easy to fabricate printed structure. The measured results show good agreement with the simulated ones. View full abstract»

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  • Tunable Filters With Nonuniform Microstrip Coupled Lines

    Page(s): 314 - 316
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (338 KB) |  | HTML iconHTML  

    A basic wideband tunable filter design based on combline topology is presented. At the presence of the parasitic effects, the structure of the filter must be modified by introducing additional degrees of freedom to the geometry of the coupled line segment. A design procedure involving iterative steps will be described. This procedure is used to design two bandpass filters with more than one octave tuning range in the UHF band. The experimental results are presented for the filter prototypes implemented using printed circuit boards and PIN diodes. View full abstract»

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  • Two-Cavity Filter With Three Transmission Zeros

    Page(s): 317 - 319
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB) |  | HTML iconHTML  

    It is well known that an N-order coupling network with source-load coupling can realize a maximum number of transmission zeros equal to N. However, in the letter, by utilizing open-circuited stubs and increasing the velocity ratio, a novel two-pole hairpin filter can obtain three transmission zeros, which can improve selectivity in the lower stopband. The filter is analyzed extensively by using the relations between the types of coupled microstrip lines and transmission zeros of transfer response. Good agreement between measured and simulated data has been demonstrated. View full abstract»

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  • A Compact Dual-Band Bandpass Filter Using Meandering Stepped Impedance Resonators

    Page(s): 320 - 322
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB) |  | HTML iconHTML  

    This letter presents a miniaturized dual-band narrow bandpass filter (BPF) using meandering stepped impedance resonators (SIRs) with a new coupling scheme, which exhibited a size reduction of 50% compared with the traditional direct coupling structure at the same frequency, while the new structure can generate three transmission zeros in the insertion loss response. To validate the design and analysis, two dual-band BPFs centered at 2.4-GHz/5.2-GHz and 2.4-GHz/5.7-GHz for WLAN application were fabricated and measured. It is shown that the measured and simulated performances are in good agreement. The BPFs achieved insertion loss of less than 2 dB and return loss of greater than 16-dB in each band. View full abstract»

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  • Effect of Printed Circuit Board Structures on Temperature-Dependent Gain Characteristics of RF Power Amplifier Chips

    Page(s): 323 - 325
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB) |  | HTML iconHTML  

    We fabricated and characterized heterojunction field effect transistor radio frequency (RF) power amplifier (PA) test fixtures, for wireless applications, with various printed circuit board (PCB) structures. The RF matching and bias circuits of the test fixtures were designed so that they had the same RF characteristics. The only source of the variation of the RF gain (S21) was different thermal characteristics of each PCB. The values of the junction temperature (TJ) and the junction-to-ambient thermal resistance (R J A) of each test fixture were shown to be changed as much as 80deg C and 30deg C / W, respectively, by the change of PCB structures. The change of Rja was shown to be originated from the change of the PCB thermal resistance, assuring that the structure of the PCB was the dominant factor in determining R J A Finally, we obtained a universal relation between S21 of the amplifier and Tj. This work suggests that thermal budget of PCB is as important as that of package in wireless RF equipments. View full abstract»

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  • An Original Demonstration of the T_{\min}/T_{o}\leq 4N Inequality for Noisy Two-Port Networks

    Page(s): 326 - 328
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (267 KB) |  | HTML iconHTML  

    The inequality Tmin/T0 les 4N for any noisy linear two-port network is completely demonstrated for the first time. A graphical interpretation to link the Lange invariant N to the minimum noise performance Tmin or Fmin is also presented. A new term DeltaN is defined and demonstrated to be invariant to lossless transformations. Its sign is important for the network to contribute as little noise as possible. Finally, conditions required for a two-port's noise figure to be either minimum or maximum are pointed out. View full abstract»

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  • Deep Submicron CMOS for Millimeter Wave Power Applications

    Page(s): 329 - 331
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (377 KB) |  | HTML iconHTML  

    This letter gives an early assessment of deep submicron planar bulk CMOS devices for millimeter wave power amplifier (PA) applications. Using load pull measurements, a record high power density of 100 mW/mm and a transducer gain of 7 dB at 35 GHz were achieved for a 40 nm physical gate length CMOS device with a total gate width of 192 mum. Furthermore a peak PAE of 33% was reached. This shows that 40 nm gate length CMOS is feasible for medium PAs in the millimeter wave region. View full abstract»

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  • Linearity Improvement of a Power Amplifier Using a Series LC Resonant Circuit

    Page(s): 332 - 334
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB) |  | HTML iconHTML  

    A radio frequency power amplifier microwave monolithic integrated circuit with a series LC resonant circuit as well as a bias control circuit for wide-band code division multiple access application is presented. The linearizer that consists of a series LC resonant circuit and base-emitter junction of a bias transistor operates as a diode rectifier circuit. A comparison between the circuits with and without the linearizer has been demonstrated. The power amplifier (PA) with the series LC resonant linearizer exhibits adjacent channel leakage ratio-1 (ACLR1) of -37.2 dBc at output power of 27 dBm, a 5.6 dB improvement compared to the circuit without the linearizer. The bias control circuit reduces consumed average dc current from 83 mA to 57 mA for efficiency improvement. The linearized PA exhibits 1-dB compression point (P1dB) of 29.3 dBm, power-added efficiency of 45.7%, and power gain of 20.6 dB at low quiescent current of 37 mA with a 3.4 V single supply. View full abstract»

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  • A Double-Sided Parallel-Strip Line Push–Pull Oscillator

    Page(s): 335 - 337
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (281 KB) |  | HTML iconHTML  

    A novel double-sided parallel-strip line (DSPSL) push-pull oscillator using two identical sub-oscillators on the opposite sides of a dielectric substrate is proposed. The two sub-oscillators, sharing a common DSPSL resonator and common ground in the middle of the substrate, generate out-of-phase fundamental signals and in-phase second harmonics. At the common DSPSL output, the second harmonics are cancelled out while the fundamental signals are well combined. By this design, an additional combiner at the output, as required by the conventional push-pull circuits, is not needed, which greatly reduces the circuit size and simplifies the design procedures of the proposed push-pull oscillator. View full abstract»

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  • 5-GHz Low Phase-Noise CMOS VCO Integrated With a Micromachined Switchable Differential Inductor

    Page(s): 338 - 340
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (359 KB) |  | HTML iconHTML  

    A 5-GHz CMOS voltage-controlled oscillator (VCO) integrated with a micromachined switchable differential inductor is reported in a 0.18 mum radio frequency-CMOS-based microelectromechanical system technology. The power consumption of the core is about 8 mW at the supply voltage of 1.8 V. A total tuning range of 470 MHz (from 5.13 GHz to 5.60 GHz) is achieved as the tuning voltage ranging from 0 V to 1.8 V. In the practical tuning range, the measured phase noise performances at 1 MHz offset are less than -125 dBc/Hz and -126 dBc/Hz when the inductor switch is turned on and off, respectively. The figure-of-merit is better than -190 dB. When compared with a contrast VCO circuit that utilizes a standard switchable differential inductor, this oscillator reaches a phase noise improvement of around 3 dB as the switch is turned on. Around 1-dB on-off phase noise difference can be achievable. View full abstract»

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  • A 48 GHz 196 dB-FOM LC VCO With Double Cap-Degeneration Negative-Resistance Cell

    Page(s): 341 - 343
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB) |  | HTML iconHTML  

    This letter presents a 48-GHz capacitively emitter-degenerated LC voltage controlled oscillator (VCO) with double cross-coupled pair showing higher and lower input capacitance than typical cross-coupled pairs. The phase noise of the proposed LC VCO is measured as 114.5 dBc/Hz at 1 MHz offset from 48 GHz carrier, and a current of 6 mA is drawn in the VCO circuit. The proposed VCO shows an excellent figure of merit of 196 dB. View full abstract»

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  • A 50 GHz Divide-by-4 Injection Lock Frequency Divider Using Matching Method

    Page(s): 344 - 346
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (752 KB) |  | HTML iconHTML  

    A fully integrated divide-by-4 frequency divider has been designed, fabricated, and measured in the standard bulk 0.18-m complementary metal-oxide semiconductor (CMOS) technology. A newly proposed matching technique was used to eliminate the unwanted low frequency mixing terms at the common node of the circuit so as to achieve a high division ratio of 4. The frequency divider exhibits a measured operation range of 5 GHz from 45.9 to 50.9 GHz. It consumes a dc power of 7.56 mW at a 1.2 V supply in the steady state operation. The phase noise of the free running divider is 88.51 dBc/Hz at 1 MHz offset and the locked divider is 110.74 dBc/Hz at 1 MHz offset. The chip size is only 0.35 mm 0.5 mm including the pad frame. To our knowledge, this divider has the highest operation frequency to date among the high division ratio injection-lock type frequency dividers in commercial CMOS 0.18-m process. View full abstract»

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  • Nonlinear Optimization of Wide-Band Harmonic Self-Oscillating Mixers

    Page(s): 347 - 349
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (828 KB) |  | HTML iconHTML  

    A new optimization method is presented for the design of wide-band harmonic self-oscillating mixers (HSOMs). High conversion gain is obtained through near-bifurcation operation and optimization of the harmonic content of the self-oscillation. Bifurcation analysis- and control-techniques are used in combination with nonlinear optimization techniques based on the use of an auxiliary generator. An 11.25-1.5 GHz third harmonic self-oscillating mixer (3HSOM) with a 2.5 dB down-conversion gain over a 1.2 GHz bandwidth has been designed. A good agreement between the simulated and experimental results has been found. View full abstract»

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  • A New Linearization Technique for CMOS RF Mixer Using Third-Order Transconductance Cancellation

    Page(s): 350 - 352
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (258 KB) |  | HTML iconHTML  

    A new third-order transconductance (gm3) cancellation technique is proposed and applied to a conventional radio frequency (RF) mixer for improving circuit linearity. The bulk-to- source voltage is applied to adjust the peak value position of gms. The cancellation of gm3 is utilized by a negative peak gm3 transistor combined in parallel with a positive peak gm3 transistor. For a single device, the measured adjacent channel power ratio (ACPR) and third-order intermodulation (IMD3) distortion are both improved over 15 dB. A Gilbert-cell mixer in commercial 0.18-mum CMOS process was designed using the proposed method to further evaluate the linearity. The compensated gm3 device is placed in the input RF gm-stage and then reducing the principle nonlinearity source of the mixer. From the experiment results, the ACPR and IMD3 of the mixer are improved about 10 and 15 dB, respectively. View full abstract»

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  • A Combined 380 GHz Mixer/Doubler Circuit Based on Planar Schottky Diodes

    Page(s): 353 - 355
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (794 KB) |  | HTML iconHTML  

    The design, fabrication and test of a combined sub-millimeter wave mixer/doubler featuring a 380 GHz sub-harmonic mixer and a 190 GHz frequency doubler on a single quartz based microstrip circuit is reported in this letter. The integrated circuit uses separate flip-chip mounted planar Schottky diode components to perform the two functions. Measurements give best double sideband mixer noise temperatures of 1625 K at 372 GHz, and a corresponding mixer conversion loss of 8 dB. The measured fixed-tuned radio frequency bandwidth extends from 368 to 392 GHz, in good agreement with simulations. This work represents the first demonstration of a single substrate combined submillimeter wave mixer/doubler. View full abstract»

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  • Adaptive Arbitrary Pulse Shaper

    Page(s): 356 - 358
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (506 KB) |  | HTML iconHTML  

    A simple, yet effective, ultra wideband pulse shaping circuit architecture is presented. The circuit enables generation of an arbitrary pulse based on in-time superposition of the excitation waveform. The proposed system addresses problems associated with spectrum management, pulse reception and equalization. The pulse shaper was implemented in planar microstrip technology to provide a fully variable waveform. View full abstract»

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  • A Compact Envelope-Memory Polynomial for RF Transmitters Modeling With Application to Baseband and RF-Digital Predistortion

    Page(s): 359 - 361
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    In this letter, a compact envelope-memory polynomial based model, suitable for forward and reverse modeling of weakly nonlinear wireless transmitters and power amplifiers (PAs) exhibiting electrical memory effects, is presented. This model is implemented in a complex gain based architecture and takes advantage of the dependency of PA nonlinearity on the magnitude of the input signal. Contrary to conventional memory polynomials, the proposed model can be implemented in baseband, as well as in radio frequency, digital predistorters. A 100-W average power transmitter is used for experimental validation of the forward and reverse models. Both forward and reverse modeling results obtained with the proposed model are comparable to that of the conventional memory polynomial. View full abstract»

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Aims & Scope

The IEEE Microwave and Wireless Components Letters (MWCL) publishes three page papers that focus on microwave theory, techniques and applications as they relate to components, devices, circuits, biological effects, and systems involving the generation, modulation, demodulation, control, transmission, and detection of microwave signals.

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