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Microwave and Wireless Components Letters, IEEE

Issue 3 • Date March 2008

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Displaying Results 1 - 25 of 27
  • Table of contents

    Publication Year: 2008 , Page(s): C1 - C4
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  • IEEE Microwave and Wireless Components Letters publication information

    Publication Year: 2008 , Page(s): C2
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  • A New Conformal FDTD(2,4) Scheme for Modeling Three-Dimensional Curved Perfectly Conducting Objects

    Publication Year: 2008 , Page(s): 149 - 151
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (197 KB) |  | HTML iconHTML  

    A new high-order conformal FDTD(2,4) scheme is proposed to solve the electromagnetic scattering from 3-D curved perfectly conducting objects. For electric field components, the update equations do not need to be modified. For magnetic field components, the inner loop is treated with the locally conformal technique, and the outer loop is unmodified. Numerical results demonstrate that the high-order conformal scheme can obtain better numerical precision under coarse grid condition compared with the low-order conformal method and the high-order staircasing approach, which in turn saves CPU time and memory. View full abstract»

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  • Mode Matching Analysis of a Tapered Coaxial Tip in a Parallel-Plate Waveguide

    Publication Year: 2008 , Page(s): 152 - 154
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (237 KB) |  | HTML iconHTML  

    A tapered coaxial tip in a parallel plate waveguide is investigated. A boundary-value problem of electromagnetic scattering from a tapered coaxial monopole is solved rigorously based on the Fourier transform, eigenfunction expansion, and mode matching. Scattering parameters are represented in a series and computed to understand the behavior of the scattering in terms of the coaxial tip geometry. View full abstract»

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  • A Novel Technique for Measuring One-Dimensional Permittivity Profiles Using a Simple Non-Commensurate Planar Structure

    Publication Year: 2008 , Page(s): 155 - 157
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB) |  | HTML iconHTML  

    A novel technique is presented for measuring one-dimensional permittivity profiles based on a simple planar structure. The measuring device consists of a transmission line loaded with open-ended stubs of non-commensurate lengths. The permittivity profile of the material under test is evaluated by simply measuring the attenuation pole frequencies in the transmitted RF signal due to the different loaded stubs. The proposed technique provides reliable results for both continuous and discontinuous permittivity profiles without requiring any a priori information of the unknown profile. Measurements using different materials have been performed resulting in good agreement with data from the literature. View full abstract»

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  • Reconstruction of Complex Permittivity of a Longitudinally Inhomogeneous Material Loaded in a Rectangular Waveguide

    Publication Year: 2008 , Page(s): 158 - 160
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (169 KB) |  | HTML iconHTML  

    In this study, an integral equation technique is presented in order to reconstruct the complex permittivity variation of a material loaded in a rectangular cross section waveguide. The problem is first reduced to the solution of a two-coupled integral equations in terms of S-parameters of the system, which contains the Green's function of the empty waveguide. The resulting inverse scattering problem for the unknown complex permittivity of the loading is solved by contrast source inversion (CSI) technique. The validity and reliability of the proposed method has been demonstrated with numerical applications. View full abstract»

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  • Characterization of Multiwalled Carbon Nanotube (MWCNT) Composites in a Waveguide of Square Cross Section

    Publication Year: 2008 , Page(s): 161 - 163
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB) |  | HTML iconHTML  

    Multiwalled carbon nanotube (MWCNT) composites are characterized within 8-10 GHz using a waveguide of square cross section. The complex permittivity is extracted and empirical expressions are obtained as a function of frequency by minimizing the difference between the measured and theoretical values of the scattering parameters. Composites with CNT concentrations ranging from 0%-20% are investigated. The square cross section of the waveguide allows for different orientations of samples to test the anisotropy of MWCNT composites. View full abstract»

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  • Harmonic and Intermodulation Distortion Output of a Radio-Frequency Plasma Capacitor

    Publication Year: 2008 , Page(s): 164 - 166
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (206 KB) |  | HTML iconHTML  

    This letter investigates the harmonic and intermodulation distortion behavior of a prototype plasma capacitor proposed for use as a radio-frequency control device. Experiments at a fundamental frequency of 900 MHz show second and third order harmonic output as high as -29 dBc and -35 dBc respectively for a 20 dBm input. Intermodulation distortion measurements are also performed at difference frequencies of 200 kHz and 1 MHz. View full abstract»

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  • BST-Varactor Tunable Dual-Mode Filter Using Variable {Z}_{C} Transmission Line

    Publication Year: 2008 , Page(s): 167 - 169
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB) |  | HTML iconHTML  

    Ferroelectric materials like barium-strontium-titanate (BST) have become attractive for microwave tunable circuit applications. This letter presents an investigation of BST-varactor tunable dual-mode filter using variable characteristic impedance or ZC transmission line. The interdigital BST varactors are fabricated and modeled, which are then deployed to realize a bandpass filter with tunable bandwidth capability. The use of tunable impedance line provides additional flexibilities in the design of microwave tunable circuits. A tunable bandpass filter of this type with a center frequency of 1.8 GHz and a bandwidth tuning ratio of 1.15:1 is demonstrated experimentally. View full abstract»

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  • A Simple Ultra-Wideband Suspended Stripline Bandpass Filter With Very Wide Stop-Band

    Publication Year: 2008 , Page(s): 170 - 172
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (233 KB) |  | HTML iconHTML  

    This letter introduces a simple ultra-wideband suspended stripline filter with a pass-band from 3.1 to 10.6 GHz and a very wide stop-band up to more than 25 GHz. The filter is realized by capacitive coupling of a quasi-lumped low-pass filter to the I/O ports. Insertion loss in the pass-band is better than 0.5 dB. The filter has a length of 13.8 mm. Excellent agreement is achieved between measured and simulated results. View full abstract»

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  • A Compact Wideband Bandpass Filter Using Transversal Resonator and Asymmetrical Interdigital Coupled Lines

    Publication Year: 2008 , Page(s): 173 - 175
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (253 KB) |  | HTML iconHTML  

    A compact wideband microstrip bandpass filter using transversal resonator and asymmetrical interdigital coupled lines is proposed in this letter. A wide passband is first constructed using transversal signal-interference technique, resulting a pair of transmission zeros at each side of the desired passband. By driving this transversal resonator with two asymmetrical interdigital coupled lines at two sides, five extra transmission zeros are generated in the lower/upper stopbands with excellent dc-choked property, thus making up a wide passband with improved out-of-band performance. This wideband microstrip filter is then designed, implemented and experimented. Good insertion/return losses, flat group delay and good out-of-band rejections are achieved as demonstrated in both simulation and experiment. View full abstract»

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  • Small Ultra-Wideband (UWB) Bandpass Filter With Notched Band

    Publication Year: 2008 , Page(s): 176 - 178
    Cited by:  Papers (58)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (378 KB) |  | HTML iconHTML  

    A compact ultra-wideband (UWB) bandpass filter (BPF) with notched band has been proposed and implemented in this letter. H-shaped slot is studied and adopted to tighten the coupling of inter-digital capacitor in order to improve the BPF's performance. Three pairs of tapered defected ground structures (DGS) are formed to assign their transmission zeros towards the out of band signal, thereby suppressing the spurious passband. Combining these two structures we obtain a small sized UWB BPF. Meander line slot is developed to reject the undesired wireless local-area network (WLAN) radio signals. An experimental UWB filter with notched band was fabricated with 35% less length as compared to an embedded open-circuited stub. The measured BPF insertion loss is less than 1.0 dB throughout the pass band of 2.8 to 10.8 GHz, the variation of group delay less than 0.20 ns in this band except for the notched band, and a wide stopband bandwidth with 20 dB attenuation up to at least 20.0 GHz. View full abstract»

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  • Quadruple-Mode Coupled-Ring Resonator Bandpass Filter With Quasi-Elliptic Function Passband

    Publication Year: 2008 , Page(s): 179 - 181
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (394 KB) |  | HTML iconHTML  

    Quadruple-mode coupled-ring resonator is used to design quasi-elliptic function bandpass filters (BPFs) with a relatively wide bandwidth. The resonator consists of a pair of coupled rings with two open stubs symmetrically tapped to the inner ring. The stubs are used to move a transmission zero near the center frequency to lower transition band. It is believed that it is the first ring resonator BPF based on the coupled-ring to create four transmission poles and four transmission zeros. Two filters with relative bandwidths of 10% and 15% are fabricated and measured. Good agreement between simulation and measurement is obtained. View full abstract»

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  • Novel Folded Waveguide Resonator Filter Using Slot Technique

    Publication Year: 2008 , Page(s): 182 - 184
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB) |  | HTML iconHTML  

    This letter presents a primary investigation into developing a compact and low-loss bandpass filter using novel folded-waveguide resonators with a footprint reduction. A slot coupling between adjacent resonators is introduced, which is characterized using full-wave electromagnetic simulations and verified experimentally. Two two-pole folded-waveguide resonator filters of this type have been designed, fabricated and tested. Simulation and measurement results are presented to validate the design and to show the advantages of this type of filter. View full abstract»

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  • Miniaturization of Microstrip Branch-Line Coupler With Dual Transmission Lines

    Publication Year: 2008 , Page(s): 185 - 187
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (325 KB) |  | HTML iconHTML  

    The dual transmission lines are proposed to replace conventional quarter-wavelength transmission lines for a compact microstrip branch-line coupler in this study. The developed coupler can be easily fabricated on the printed circuit board without lumped element; moreover, its size is greatly reduced compared to the conventional branch-line coupler. Furthermore, simulated and measured frequency responses match well to validate the proposed coupler with dual transmission lines. View full abstract»

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  • A Dual-Band Out-of-Phase Power Divider

    Publication Year: 2008 , Page(s): 188 - 190
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB) |  | HTML iconHTML  

    This letter proposes a novel out-of-phase power divider that operates at two arbitrary frequencies. Because of the use of the balanced transmission line, namely the double-sided parallel-strip line (DSPSL), the out-of-phase feature between the two output ports can be made frequency-independent. The power divider employs three lumped components (an inductor L, a capacitor C and a resistor R) in serial connection to achieve isolation between the two output ports. The design equations are derived using the odd-mode and even-mode analysis. Experimental results show that good matching, isolation and amplitude balance are simultaneously achievable for both of the two operating frequency bands. View full abstract»

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  • A 3-dB Quadrature Coupler Using Broadside-Coupled Coplanar Waveguides

    Publication Year: 2008 , Page(s): 191 - 193
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (469 KB) |  | HTML iconHTML  

    A 3-dB quadrature coupler which combines the advantages of broadside-coupling and coplanar waveguide structure suitable for a single-layer printed circuit board (PCB) circuit design is proposed. Compared to the recently published broadside-coupled structures, the proposed coupler can easily be realized in a single-layer substrate by using PCB manufacturing processes to eliminate the effects of uncertain factors from a multi-layer substrate. With the operation bandwidth ranging from 2.1 to 2.7 GHz, the measured return loss and isolation are all better than 19dB, and the insertion losses and relative phase difference between the direct and coupled ports are at 3.2 plusmn 0.1 dB and 90 plusmn 0.6deg, respectively. The dimension of the coupler is 2.1 cm times 1.9 cm. View full abstract»

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  • A Novel Reduced-Size Rat-Race Broadside Coupler and Its Application for CMOS Distributed Sub-Harmonic Mixer

    Publication Year: 2008 , Page(s): 194 - 196
    Cited by:  Papers (10)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (726 KB) |  | HTML iconHTML  

    A broadband distributed sub-harmonic resistive field effect transistor mixer with a novel modified rat-race broadside coupler using a 0.13-mum CMOS foundry process is presented in this letter. Using the broadside coupler, a reduced-size rat-race is fabricated with a compact size of 110 times 80 mum2. From the measurement results, the mixer achieved a conversion loss of 12 dB from 32 to 70 GHz of RF frequency. The passive sub-harmonic mixer has zero power consumption. With the modified rat-race broadside coupler, the mixer achieves a good LO-IF isolation of better than 30 dB and a compact core chip size of 0.55 times 0.4 mm2. View full abstract»

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  • A 2.4 GHz Fully Integrated Cascode-Cascade CMOS Doherty Power Amplifier

    Publication Year: 2008 , Page(s): 197 - 199
    Cited by:  Papers (10)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB) |  | HTML iconHTML  

    This letter presents the first CMOS Doherty power amplifier (PA) fully integrated on chip. The "cascode-cascade" amplifier architecture is proposed to get rid of the bulky power splitter and facilitate the integration. The quarter wavelength transmission lines are replaced by the lumped component networks such that the whole amplifier circuit can be squeezed into the die size of 1.97 times 1.4 mm2. Fabricated in 0.18 mum CMOS technology, the 3.3 V PA achieves 12 dB power gain. The measured output power and power added efficiency (PAE) at P1 dB are more than 21 dBm and 14%, respectively. The PAE at 7 dB back-off from P1 dB is above 10% and the PAE degradation is less than 29%. View full abstract»

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  • A Parallel Power Amplifier With a Novel Mode Switching Control

    Publication Year: 2008 , Page(s): 200 - 202
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (287 KB) |  | HTML iconHTML  

    Two parallel operating power amplifiers (PAs) are controlled by a novel mode switch for high efficiencies at both the back-off power region and high power region. The mode switch is realized by the base-collector (BC) junction diode which reuses the dc current of the low power mode amplifier. A 836 MHz CDMA PA has been demonstrated using InGaP/GaAs heterojunction bipolar transistor with fully integrated matching component for small package and low cost. It shows a 13 mA idle current, 15.4% power added efficiency (PAE), ACPR1 at 16 dBm of the low power mode operation and a 40.5% PAE, ACPR1 at 28 dBm of the high power mode operation. View full abstract»

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  • Distributed Amplifier With Blue Noise Active Termination

    Publication Year: 2008 , Page(s): 203 - 205
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (251 KB) |  | HTML iconHTML  

    Active terminations can be used to reduce the low frequency noise figure of distributed amplifiers. In this letter we show extension and improvement upon previous active termination techniques. We use a combination of active and passive elements to create a termination with a blue noise spectrum rather than a broadband white noise spectrum. The novel technique is tested in a 180 nm CMOS distributed amplifier and demonstrates a 44% reduction in low frequency noise with no impact on gain, bandwidth or matching when compared to conventional design. View full abstract»

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  • RF Class-E Power Amplifier Design Based on a Load Line-Equivalent Capacitance Method

    Publication Year: 2008 , Page(s): 206 - 208
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (345 KB) |  | HTML iconHTML  

    In this research work, an alternative methodology to design radio frequency (RF) class-E amplifier is proposed and verified. The conventional design procedure starts with a switch idealization of the device and extraction of the output capacitance based on S parameter measurements. Since these ideal conditions lead to non-optimal values at microwave frequencies, an optimization procedure on these values, using a non-linear model of the device, has to be applied in order to obtain higher performance. Unlike this legacy procedure, the proposed method starts the design of the RF class E power amplifier with the non-linear model directly to determine a more representative value of the equivalent capacitance, and thereby considering all the non-ideal and non-linear features of the device. View full abstract»

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  • A 60 GHz SiGe-HBT Power Amplifier With 20% PAE at 15 dBm Output Power

    Publication Year: 2008 , Page(s): 209 - 211
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (285 KB) |  | HTML iconHTML  

    A monolithic power amplifier (PA) operating in the 60 GHz band is presented. The circuit has been designed utilizing an advanced 0.25 SiGe-heterojunction bipolar transistor (HBT) technology, featuring npn transistors with and . A two-stage cascode architecture has been chosen for the implementation. Design techniques and optimization procedure are explained in detail. Measurements show a small signal gain of 18.8 dB and an output power of 14.5 dBm under 1 dB gain compression at 61 GHz. At this frequency, the saturated output power is 15.5 dBm and the peak power added efficiency (PAE) is 19.7%. To our knowledge, this is the highest PAE reported so far for a monolithic 61 GHz PA in SiGe-HBT technology. View full abstract»

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  • A Sub-2 dB NF Dual-Band CMOS LNA for CDMA/WCDMA Applications

    Publication Year: 2008 , Page(s): 212 - 214
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (518 KB) |  | HTML iconHTML  

    This letter presents the design and experimental results of a 1.8/2.14 GHz dual-band CMOS low-noise amplifier (LNA), which is usable for code division multiple access and wideband code division multiple access applications. To achieve the narrow-band gain and impedance matching at both bands, an extra capacitor in parallel with the Cgs of the main transistor and a harmonic tuned load are switched. Except for the output blocking capacitor and series inductor, all components are integrated on a single-chip. The LNA is designed using a 0.13mum- CMOS process and employs a supply voltage of 1.5 V and dissipates a dc power of 7.5 mW. The measured performances are gains of 14.54 dB and 16.6 dB, and noise figures of 1.75 dB and 1.97 dB at the two frequency bands, respectively. The linearity parameters of and P1dBin are -16dBm and -5.8 dBm at the 1.8 GHz, -14.8 dBm and -5.3 dBm at the 2.14 GHz, respectively. View full abstract»

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  • A 220 GHz (G-Band) Microstrip MMIC Single-Ended Resistive Mixer

    Publication Year: 2008 , Page(s): 215 - 217
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (840 KB) |  | HTML iconHTML  

    This letter presents the design and characterization of a 220 GHz microstrip monolithic microwave integrated circuit single-ended resistive mixer in a 0.1 GaAs mHEMT technology. A conversion loss as low as 8.7 dB is obtained, limited by the available local oscillator (LO) power (1.5 dBm) in the measurement setup. The radio frequency (RF) bandwidth is also limited by the measurement setup, but the mixer demonstrates a flat response over the measured 200 to 220 GHz frequency range. Furthermore, measured intermediate frequency bandwidth, 1-dB input compression point, LO-to-RF isolation, and reflection coefficients are presented and discussed. 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