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Microwave and Wireless Components Letters, IEEE

Issue 2 • Date Feb. 2008

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Displaying Results 1 - 25 of 29
  • Table of contents

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

    Page(s): C2
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  • Broadband Radial Waveguide Spatial Combiner

    Page(s): 73 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (238 KB) |  | HTML iconHTML  

    A broadband eight-way spatial combiner using coaxial probes and radial waveguides has been proposed and designed. The simple electromagnetic modeling for the radial waveguide power divider/combiner has been developed using equivalent-circuit method. The measured 10-dB return loss and 1-dB insertion loss bandwidth of this waveguide spatial combiner are all demonstrated to be about 8 GHz. View full abstract»

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  • An Iterative Unconditionally Stable LOD–FDTD Method

    Page(s): 76 - 78
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (134 KB) |  | HTML iconHTML  

    We present an iterative, unconditionally stable locally-one-dimensional (LOD) finite-difference time-domain (FDTD) method based on the use of an iterative fixed-point correction to reduce the splitting error. Numerical examples are used to illustrate the gain in accuracy of the proposed method versus the conventional LOD-FDTD method and the improved computational efficiency versus the iterative alternating-direction-implicit (ADI)-FDTD method. View full abstract»

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  • Wide Band Metallic Waveguide With In-Line Dielectric Rods

    Page(s): 79 - 81
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (158 KB) |  | HTML iconHTML  

    Conventional rectangular metallic waveguides are seldom used at frequencies higher than twice the cutoff frequency because of higher mode propagation. Single-mode propagation is available for a metallic waveguide with arrayed dielectric rods at the center of the waveguide in the frequency under twice the cutoff frequency region using the TE20 mode, and in the frequency over twice the cutoff frequency region using the TE2o mode. If the metallic waveguide and dielectric loss tangent are assumed to be WR-90 (fc ap6.55 GHz) and 3times10-4, respectively, then the attenuation constants are smaller than 0.25 dB/m in the frequency range from 7 to 10 GHz, 15 to 16.5 GHz, and from 17.2 to 21 GHz. View full abstract»

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  • A Patterned Dielectric Support Process for High Performance Passive Fabrication

    Page(s): 82 - 84
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (647 KB) |  | HTML iconHTML  

    This letter presents a micromachining process to effectively reduce substrate loss via a structure of patterned oxide/nitride fins on a silicon substrate with a resistivity of 1 Omega-cm. Experimental results demonstrate that the insertion loss of a coplanar waveguide (CPW) deposited on the structure can be lowered to the value of 4.33 dB/cm at 40 GHz. Meanwhile, an analytical model is developed to predict the characteristics of the CPW. View full abstract»

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  • A Dual-Band Wilkinson Power Divider

    Page(s): 85 - 87
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (116 KB) |  | HTML iconHTML  

    A new scheme is proposed for the dual-band operation of the Wilkinson power divider/combiner. The dual band operation is achieved by attaching two central transmission line stubs to the conventional Wilkinson divider. It has simple structure and is suitable for distributed circuit implementation. View full abstract»

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  • Miniature Dual-Band Filter Using Quarter Wavelength Stepped Impedance Resonators

    Page(s): 88 - 90
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (609 KB) |  | HTML iconHTML  

    A miniature dual-band filter using quarter wavelength (lambdag/4) stepped impedance resonators (SIRs) is proposed. Short and open SIRs are coupled together to realize lower and upper passbands, respectively. Miniaturization is achieved due to the use of lambdag/4 resonators and a combline coupling structure. Two transmission zeros in a mid-stopband and one in each lower and upper stopbands are achieved. In order to see the capability of this structure to achieve different second passband frequencies, two dual band filters at frequencies of 2.45/5.25 GHz and 2.45/5.75 GHz are realized. Measured insertion losses are 1.3 dB and 2.3 dB and return losses are better than 17 dB and 18 dB at the first and second passband frequencies, respectively, with a mid-stopband attenuation better than 30 dB. The size of the filter is as compact as 19.0 times 5.2 mm2 on a RO 4003C (epsivr = 3.38, h = 0.81 mm) substrate. View full abstract»

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  • Design of a Wide Stopband Microstrip Bandpass Filter With Asymmetric Resonators

    Page(s): 91 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (207 KB) |  | HTML iconHTML  

    In this letter, a novel microstrip bandpass filter (BPF) with asymmetric resonators is presented. With the asymmetric structure and capacitively loaded coupling, a wide bandwidth with sufficient rejection level can be achieved easily. A full-wave electromagnetic simulator IE3D is used, and the prototype of the BPF is fabricated and measured. Comparisons of simulated results and experimental data are shown; moreover, good match validates the proposed filter. View full abstract»

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  • A 3.3 mW K-Band 0.18- \mu m 1P6M CMOS Active Bandpass Filter Using Complementary Current-Reuse Pair

    Page(s): 94 - 96
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (450 KB) |  | HTML iconHTML  

    This letter presents a low-power active bandpass filter (BPF) at K-band fabricated by the standard 0.18 mum 1P6M CMOS technology. The proposed filter is evolved from the conventional half-wavelength resonator filter, using the complementary-conducting-strip transmission line (CCS TL) as the half-wavelength resonator. Furthermore, the complementary MOS cross-couple pair is proposed as a form of current-reuse scheme for achieving low-power consumption and high Q-factor simultaneously. The simulated results indicate that the Q-factor of the proposed half-wavelength resonator can be boosted from 9 to 513 at 25.65 GHz compared with the resonator enhanced by the nMOS cross-couple pair to Q-factor of merely 43 under the same power consumption. The proposed active BPF of order two occupies the chip area of 360 mum times 360 mum without contact pads. The measured results show that the center frequency of the active BPF is 22.70 GHz and a bandwidth of 1.68 GHz (7.39 %). The measured P1 dB and noise figure at 22.70 GHz are -7.65 dBm and 14.05 dB, respectively. There is a 56.84 dB suppression between the fundamental tone and the second harmonic when the input power is -11.26 dBm. While showing 0 dB loss and some residual gain, the active BPF consumes 2.0 mA at 1.65 V supply voltage with maximum of 0.15 dB insertion loss and 9.96 dB return loss at pass band. View full abstract»

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  • Miniaturized Dual-Mode Ring Resonator Bandpass Filter With Microstrip-to-CPW Broadside-Coupled Structure

    Page(s): 97 - 99
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (370 KB) |  | HTML iconHTML  

    A microstrip-to-coplanar waveguide broadside-coupled section is used to replace a 34-section of the conventional dual-mode 1-ring resonator filter for circuit area miniaturization. It is believed that it is a new idea to incorporate the broadside-coupled section into a ring resonator filter for size reduction. For design purpose, some important characteristics of the broadside-coupled lines are investigated. In experiments, two realized circuits show only 19.4% of the area of a uniform ring. Measured responses show good agreement with simulation. View full abstract»

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  • Lifetime Measurements on a High-Reliability RF-MEMS Contact Switch

    Page(s): 100 - 102
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (921 KB) |  | HTML iconHTML  

    Radio frequency microelectromechanical systems (RF MEMS) cantilever contact switches have been tested for lifetime. The mean cycles-to-failure measured on an ensemble of switches was 430 billion switch cycles. The longest lifetime exhibited without degradation of the switch was 914 billion switch cycles. The devices were switched at 20 kHz with an incident RF frequency of 10 GHz and an incident RF power of 20 dBm. Testing was performed continuously over a period of approximately 18 months. The switches were operated in a cold-switched mode. View full abstract»

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  • An Electronic UWB Continuously Tunable Time-Delay System With Nanosecond Delays

    Page(s): 103 - 105
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (379 KB) |  | HTML iconHTML  

    We propose and demonstrate an electronic system achieving continuously tunable time-delays with nanosecond-scale delay excursions for ultra-wideband signals. Our demonstration system yields an adjustable delay of up to 1.6 ns for input signals spanning 3 to 7 GHz. The key component is a dispersive length of microstrip line created by etching a chirped electromagnetic bandgap structure in the conducting strip. View full abstract»

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  • A Full-360 ^{\circ} Reflection-Type Phase Shifter With Constant Insertion Loss

    Page(s): 106 - 108
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB) |  | HTML iconHTML  

    A new reflection-type phase shifter with a full 360deg relative phase shift range and constant insertion loss is presented. This feature is obtained by incorporating a new cascaded connection of varactors into the impedance-transforming quadrature coupler. The required reactance variation of a varactor can be reduced by controlling the impedance ratio of the quadrature coupler. The implemented phase shifter achieves a measured maximal relative phase shift of 407deg, an averaged insertion loss of 4.4 dB and return losses better than 19 dB at 2 GHz. The insertion-loss variation is within plusmn0.1 and plusmn0.2 dB over the 360deg and 407deg relative phase shift tuning range, respectively. View full abstract»

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  • A Novel Miniature 1–22 GHz 90 ^{\circ} MMIC Phase Shifter with Microstrip Radial Stubs

    Page(s): 109 - 111
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (406 KB) |  | HTML iconHTML  

    A novel miniature ultra wide bandwidth 90 monolithic microwave integrated circuit phase shifter with microstrip radial stubs operated from 1 to 22 GHz is presented. The phase shifter exhibits a high performance. Within the whole bandwidth from 1 to 22 GHz, the phase error of the phase shifter is less than 3deg, the return losses of the different phase shift states are more than 14 dB, the insertion loss of all phase shift states are within 3.3plusmn0.5 dB. The chip size of this phase shifter is 1.4 mm times 1.8 mm times 0.1 mm. The proposed phase shifter can be compatible with different polarity control signals without the need of drivers and can also be compatible with either analogue or digital control signals. View full abstract»

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  • Compact CPW-MS-CPW Two-Stage pHEMT Amplifier Compatible With Flip Chip Technique in V-Band Frequencies

    Page(s): 112 - 114
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (582 KB) |  | HTML iconHTML  

    The V-band coplanar waveguide (CPW)-microstrip line (MS)-CPW two-stage amplifier with the flip-chip bonding technique is demonstrated using 0.15 mum AlGaAs/InGaAs pseudomorphic high electron mobility transistor technology. The CPW is used at input and output ports for flip-chip assemblies and the MS transmission line is employed in the interstage to reduce chip size. This two-stage amplifier employs transistors as the CPW-MS transition and the MS-CPW transition in the first stage and the second stage, respectively. The CPW-MS-CPW two-stage amplifier has a gain of 14.8 dB, input return loss of 10 dB and output return loss of 22 dB at 53.5 GHz. After the flip-chip bonding, the measured performances have almost the same value. View full abstract»

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  • An Approximation of Volterra Series Using Delay Envelopes, Applied to Digital Predistortion of RF Power Amplifiers With Memory Effects

    Page(s): 115 - 117
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (246 KB) |  | HTML iconHTML  

    In this letter, a new model for digital predistortion (DPD) of radio frequency power amplifiers for wide-band applications is proposed. The model is based on a spline approximation of Volterra series by considering second-order cross-terms. The advantage of the spline cross-term model is a reduction in the number of model parameters. We further reduce the model order by operating on delayed envelope samples, rather than the complex baseband samples. A block of wide-band code-division multiple access signal is sent through a 90 W class-AB power amplifier, based on the freescale LDMOS output device, and the input/output baseband samples were used to identify the DPD parameters. View full abstract»

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  • A Highly Linear Wideband CMOS Low-Noise Amplifier Based on Current Amplification for Digital TV Tuner Applications

    Page(s): 118 - 120
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (219 KB) |  | HTML iconHTML  

    A differential wideband low-noise amplifier (LNA) based on the current amplification scheme is presented for digital TV tuners. In order to highly improve the linearity and exploit the noise cancellation, a common-gate stage with positive current feedback is integrated in parallel with a common-source stage using the current mirror amplifier. The proposed 0.18-mum CMOS LNA exhibits a power gain of 20.5 dB, an IIP3 of 2.7 dBm, an IIP2 of 43 dBm, and an average noise figure of 3.3 dB with 32.4 mW power consumption at a 1.8-V power supply and 0.12 mm2 area. View full abstract»

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  • 80-GHz Tuned Amplifier in Bulk CMOS

    Page(s): 121 - 123
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (410 KB) |  | HTML iconHTML  

    An 80-GHz six-stage common source tuned amplifier has been demonstrated using low leakage (higher VT) NMOS transistors of a 65-nm digital CMOS process with six metal levels. It achieves power gain of 12 dB at 80 GHz with a 3-dB bandwidth of 6 GHz, noise figures (NF's) lower than 10.5 dB at frequencies between 75 and 81 GHz with the lowest NF of 9 dB. IP1 dB is -21 dBm and IIP3 is -11.5 dBm. The amplifier consumes 27 mA from a 1.2 V supply. At VDD = 1.5 V and 33 mA bias current, NF is less than 9.5 dB within the 3-dB bandwidth and reaches a minimum of 8 dB at 80 GHz. View full abstract»

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  • A 86 to 108 GHz Amplifier in 90 nm CMOS

    Page(s): 124 - 126
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (836 KB) |  | HTML iconHTML  

    This letter presents a CMOS amplifier with 22 GHz 3-dB bandwidth ranging from 86 to 108 GHz. The amplifier is implemented in 90 nm mixed signal/radio frequency (RF) CMOS process using three-stage cascode RF NMOS configuration. It achieves a peak gain of 17.4 dB at 91 GHz from the measured results. To our knowledge, this is the highest frequency CMOS amplifier reported to date. View full abstract»

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  • 5.7 GHz Gilbert I/Q Downconverter Integrated With a Passive LO Quadrature Generator and an RF Marchand Balun

    Page(s): 127 - 129
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (659 KB) |  | HTML iconHTML  

    A 5.7 GHz downconversion mixer is demonstrated in this letter using 0.35 mum SiGe BiCMOS technology. A quarter-wavelength coupled line and two center-tapped transformers are utilized to generate differential quadrature LO signals. A miniaturized Marchand balun is placed before the common-base-configured RF input stage of each Gilbert mixer to generate balanced RF signals. All the reactive passive elements are placed directly on the standard silicon substrate. The 5.7 GHz downconverter achieves 7 dB conversion gain, 26dBm 1dB, and 18dBm IIP3 at the power consumption of 3.875 mW and 2.5 V supply voltage. View full abstract»

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  • A CMOS K-Band Quadrature Generator

    Page(s): 130 - 132
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB) |  | HTML iconHTML  

    This letter presents a K-band quadrature signal generator in a standard 0.13 mu m CMOS process. The quadrature generator operates from 18 to 21 GHz. A maximum output power of -3.7 dBm (per I or Q channel) is achieved, and the down converted signal suppression is >25 dB at the operating bandwidth. A measured sideband rejection ratio >30 dB is achieved from 19 to 21 GHz, with a peak of >40 dB at 19.5-20.5 GHz. The current consumption of the quadrature generator is 49-54 mA from a 2-2.5 V supply with an effective chip area of 0.51times 0.44 mm2 . To the author's knowledge, this is the first demonstration of a K-band quadrature signal generator with high spectral purity and quadrature accuracy. View full abstract»

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  • A 12-GHz Fully Integrated Cascode CMOS LC VCO With Q -Enhancement Circuit

    Page(s): 133 - 135
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (338 KB) |  | HTML iconHTML  

    A fully integrated complementary metal oxide semiconductor (CMOS) cascode LC voltage controlled oscillator (VCO) with Q-enhancement technique has been designed for high frequency and low phase noise. The symmetrical cascode architecture is implemented with negative conductance circuit for improving phase noise performance in 0.18 mum CMOS technology. The measured phase noise is -110.8 dBc/Hz at the offset frequency of 1 MHz. The tuning range of 630 MHz is achieved with the control voltage from 0.6 to 1.4 V. The VCO draws 4.5 mA in a differential core circuit from 1.8 V supply. View full abstract»

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  • Low Phase-Noise and Low-Power CMOS VCO Constructed in Current-Reused Configuration

    Page(s): 136 - 138
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (581 KB) |  | HTML iconHTML  

    A Ku-band CMOS voltage-controlled oscillator (VCO) constructed in a modified current-reused configuration is presented in this letter. Two dc level shifters combined into two metal-insulator-metal capacitors are adopted to solve the transconductance and load mismatch problems of the conventional current-reused VCO for obtaining more symmetrical oscillation signals and lowering the phase noise of oscillator. A prototype was designed and measured to verify the design concept. The measurement results demonstrate the central oscillation signal of 16 GHz to be associated with the 900 MHz tuning range and -111 dBc/Hz phase noise at 1 MHz offset. The power consumption of the VCO core is only 8.1 mW. The measurement result evaluated by means of a figure of merit is about -186.8 dBc/Hz. View full abstract»

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  • Integrated VCO With Up/Down Converter for Si-Based 60 GHz WPAN Applications

    Page(s): 139 - 141
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (350 KB) |  | HTML iconHTML  

    This letter presents the design and implementation of the largest reported bandwidth of a 60 GHz up/down converter with an integrated voltage controlled oscillator (VCO) in a low-cost 0.18 mum silicon-germanium process. The up/down conversion is achieved using the 2X sub-harmonic passive mixing with anti-parallel diode pairs. A 30 GHz cross-coupled VCO is designed, optimized and integrated with the sub-harmonic mixer through a cascode amplifier to meet the local oscillator power requirements. The fully integrated chip takes only 1.5 mm2 of silicon die area and consumes only 40 mW of dc power for a measured conversion loss of 12 dB at 61.5 GHz. The integrated up/down converter is measured to have greater than 9 GHz double-sided 3-dB RF bandwidth suitable for wideband high data-rate WPAN transceiver requirements. The VCO and VCO-amplifier test structures are separately fabricated and measured to have a phase noise as low as -105 dBc/Hz at 1 MHz offset with a tuning range of 2.3 GHz. 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.

Full Aims & Scope