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Microwave and Wireless Components Letters, IEEE

Issue 6 • Date June 2014

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Displaying Results 1 - 25 of 27
  • 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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  • Trade-Offs for Unconditional Stability in the Finite-Element Time-Domain Method

    Page(s): 361 - 363
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (706 KB) |  | HTML iconHTML  

    We discuss basic trade-offs in the application of unconditionally-stable time-updating schemes for the finite-element time-domain solution of Maxwell's equations. Particular attention is given to the case of large Courant-Friedrichs-Lewy number, where the conventional thought holds that unconditionally stable schemes provide marked advantage over conditionally stable ones. View full abstract»

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  • Rapid EM-Driven Design of Compact RF Circuits By Means of Nested Space Mapping

    Page(s): 364 - 366
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB) |  | HTML iconHTML  

    A methodology for rapid design of RF circuits constituted by compact microstrip resonant-cells (CMRCs) is presented. Our approach exploits nested space mapping (NSM) technology, where the inner SM layer is used to correct the equivalent circuit model at the CMRC level, whereas the outer layer enhances the coarse model of the entire structure under design. We demonstrate that NSM dramatically improves performance of surrogate-based optimization of composite CMRC-based structures. It is validated using four examples of UWB microstrip matching transformers (MTs) and compared to previous attempts to surrogate-based compact structure design. View full abstract»

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  • Miniaturized Ultra-Wideband Bandpass Filter Using Bridged-T Coil

    Page(s): 367 - 369
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (743 KB) |  | HTML iconHTML  

    In this letter, a miniaturized ultra-wideband bandpass filter based on thin-film integrated passive device process is proposed. The multi-mode resonator is adopted to achieve a wide bandwidth from 3.1 to 10.6 GHz. By using the bridged-T coil to replace the transmission line of multi-mode resonator, the circuit size is largely reduced while the multi-mode property can be retained. The filter size without pads is 2.21 mm × 1.04 mm, which is only about 0.050 λ0 ×0.024 λ0 at the center frequency of 6.85 GHz. To our knowledge, this is the smallest multi-mode resonator filter ever published. View full abstract»

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  • Phase Property of Central-Symmetric Four-Ports Applied to Quadrature Directional Coupler Design in Asymmetric Coupled-Line Technology

    Page(s): 370 - 372
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (422 KB) |  | HTML iconHTML  

    Properties of ideally matched lossless four-port networks having central symmetry have been investigated. It has been shown that such networks feature ideal quadrature differential phase characteristics. It is shown that this unique property can be utilized for phase improvement of asymmetric coupled-line directional couplers. The presented theoretical investigation has been proven by measurements of two different directional couplers with a central symmetry designed in technology of multilayer asymmetric coupled lines. View full abstract»

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  • Switchable and High-Isolation Diplexer With Wide Stopband

    Page(s): 373 - 375
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (867 KB) |  | HTML iconHTML  

    This letter presents a switchable diplexer composed of a stepped-impedance distributed coupling feeding line, four different quarter-wavelength stepped-impedance resonators (SIRs), two shunt open stubs, two p-i-n diodes, and bias circuitry. Compared with previous works, the proposed circuit features compactness, wide stopband, high selectivity, and independently switchable channels. To suppress harmonics, various quarter-wavelength SIRs with the same fundamental frequency but harmonic frequencies in stagger are used. Open stubs are also adopted to achieve an optimal stopband response. To meet the demands of reconfigurable application in wireless communication systems, switching circuit is integrated into the proposed diplexer to develop a switchable diplexer. In this way, mismatch losses during integration and circuit size are both further reduced. Simulations and measurements have been carried out to verify the design concept with good agreement. View full abstract»

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  • Reduced-Length Two-Section Directional Couplers Designed as Coupled-Line Sections Connected With the Use of Uncoupled Lines

    Page(s): 376 - 378
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (557 KB) |  | HTML iconHTML  

    Broadband coupled-line directional couplers having the properties of two-section coupled-line directional couplers are proposed. The presented couplers are composed of two-coupled line sections having the same coupling coefficient which are connected with the use of two sections of uncoupled transmission lines. It is shown that in such a structure it is possible to achieve an equal-ripple coupling characteristic similar to the coupling response of classic-two section coupled-line couplers. It is also shown that, in comparison to the classic counterparts, in the proposed couplers the required coupling between the coupled-lines is slightly weaker and the overall electrical length is reduced. The theoretical analysis and measurement results of a 3 dB directional coupler operating at a center frequency of 1.8 GHz are presented. View full abstract»

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  • Dual-Band Substrate Integrated Waveguide Balun Bandpass Filter With High Selectivity

    Page(s): 379 - 381
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (842 KB) |  | HTML iconHTML  

    A new method of designing a dual-band balun bandpass filter (BPF) with high selectivity is proposed and implemented by taking advantage of the existence of multiple substrate integrated waveguide (SIW) cavity modes. The major design concept applied in this letter is based on two mechanisms: one is by properly placing the output ports to achieve the balanced output for both passbands, and the other is by taking cross coupling of higher/lower order modes to achieve transmission zeros (TZs) at each side of the passband. Two internal coupling slots are involved to separately control the coupling level between cascaded cavities for each passband. A prototype operating at 9.0 GHz and 9.8 GHz has been realized and shows the desired filtering performance. The differences between the two outputs are within 180°±2° in phase and 0.6 dB in magnitude across the two passbands. Measured frequency responses agree well with the simulated ones in this work. View full abstract»

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  • A Lumped-Element Directional Coupler With High Isolation for Mobile RFID Reader

    Page(s): 382 - 384
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (555 KB) |  | HTML iconHTML  

    A lumped-element directional coupler with a high isolation characteristic for mobile RFID reader systems is proposed and experimentally demonstrated. Compared with the conventional lumped-element circuit, the proposed structure utilizes compensation capacitors and achieves a very high isolation despite low quality factor on-chip inductors. It was fabricated on a high-resistivity silicon substrate and showed an isolation of 79 dB, a coupling level of 14.8 dB, and an insertion loss of 1.74 dB at 910 MHz. View full abstract»

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  • Compact and High-Isolation Diplexer Using Dual-Mode Stub-Loaded Resonators

    Page(s): 385 - 387
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (685 KB) |  | HTML iconHTML  

    A novel compact microstrip diplexer for UMTS and WCDMA system is proposed in this letter. The diplexer is mainly composed of three dual-mode stub-loaded microstrip resonators. Two resonant modes of a stub-loaded resonator work together with one mode produced by the common stub-loaded resonator to form a passband or operating band of the proposed diplexer. Extensive study is then conducted on coupling scheme involved in various parts of the diplexer. In particular, the resonance of a resonator is employed to create a desired transmission zero in the stopband, thus improving the isolation between two passbands. The proposed diplexer is in final fabricated and measured. A good agreement between EM simulated and measured results evidently validates the proposed methodology. View full abstract»

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  • A Harmonic Suppressed Bandpass Filter and its Application in Diplexer

    Page(s): 388 - 390
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (602 KB) |  | HTML iconHTML  

    A multilayer bandpass filter (BPF) with harmonic suppression using meander line inductor and interdigital capacitor (MLI-IDC) resonant structure is presented in this letter. The BPF is fabricated with three unit cells and its measured passband center frequency is 2.56 GHz with a bandwidth of 0.38 GHz and an insertion loss of 1.5 dB. The harmonics are suppressed up to 11 GHz. A diplexer using the proposed BPF is also presented. The proposed diplexer consists of 4.32 mm sized unit cells to couple 2.5 GHz signal into port 2, and 3.65 mm sized unit cells to couple 3.7 GHz signal into port 3. The notch circuit is placed on the output lines of the diplexer to improve isolation. The proposed diplexer has demonstrated insertion loss of 1.35 dB with 0.45 GHz bandwidth in port 2 and 1.73 dB insertion loss with 0.44 GHz bandwidth in port 3. The isolation is better than 18 dB in the first passband with 38 dB maximum isolation at 2.5 GHz. The isolation in the second passband is better than 26 dB with 45 dB maximum isolation at 3.7 GHz. View full abstract»

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  • Balance-Compensated Asymmetric Marchand Baluns on Silicon for MMICs

    Page(s): 391 - 393
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (823 KB) |  | HTML iconHTML  

    The balance compensating techniques for asymmetric Marchand balun are presented in this letter. The amplitude and phase difference are characterized explicitly by S21 and S31, from which the factors responsible for the balance compensating are determined. Finally, two asymmetric Marchand baluns, which have normal and enhanced balance compensation, respectively, are designed and fabricated in a 0.18 μm CMOS technology for demonstration. The simulation and measurement results show that the proposed balance compensating techniques are valid in a very wide frequency range up to millimeter-wave (MMW) band. View full abstract»

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  • Small-Versus Large-Signal Extraction of Charge Models of Microwave FETs

    Page(s): 394 - 396
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (645 KB) |  | HTML iconHTML  

    In this letter we extract the parameters of the charge equations of a microwave transistor nonlinear model which is available in commercial CAD tools. In particular, the charge model parameters are extracted starting from small- and large-signal measurements. A better accuracy can be achieved when using large-signal measurements since the model parameters are obtained from experimental data which better reproduce the actual operating condition of the device under test. An advanced 0.15×300 μm2 pHEMT in GaAs technology, aimed at cold-FET mixer design, is considered as case study. View full abstract»

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  • Design of A Push-Push and Push-Pull Oscillator Based on SIW/SICL Technique

    Page(s): 397 - 399
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (724 KB) |  | HTML iconHTML  

    In this letter, the design of a Push-Push and Push-Pull oscillator based on substrate integrated waveguide (SIW) and substrate integrated coaxial line (SICL) technique is presented. Differential-phase lock of the sub-oscillators is realized with the SIW cavity at fundamental TE110 mode, thus simplifying the oscillator design procedure. Based on the SIW and SICL technique, a broadband magic-T is utilized for combining the desired signal and cancelling the undesired signal for both Push-Push and Push-Pull output. The prototype of the Push-Push and Push-Pull oscillator is designed and fabricated. Measured results show that the proposed oscillator has f0 suppression of -13.1 dBc at the Push-Push port, and 2f0 suppression of -24.3 dBc at the Push-Pull port. Compared with the conventional single oscillator, the phase noise is improved by 2.5 ~ 3.2 dB at 100 kHz through 1 MHz offset for the desired f0 and 2f0 output signals. View full abstract»

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  • A Low-Loss and High Isolation D-Band SPDT Switch Utilizing Deep-Saturated SiGe HBTs

    Page(s): 400 - 402
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (617 KB) |  | HTML iconHTML  

    A single-pole double-throw switch, utilizing double-shunt, deep-saturated HBTs is implemented in a 0.13 μm SiGe BiCMOS technology, occupying 0.36 mm2 of IC area. A superior switch performance is identified when HBTs are operated in saturation regime, and state of the art performance is achieved at D-band frequencies from 96 to 163 GHz. Measurements show a minimum insertion loss of 2.6 dB at 120 and 150 GHz, a highest isolation of 29 dB at 120 GHz and an input 1 dB compression point of 17 dBm at 94 GHz, outperforming similar implementations in deep-scaled CMOS technologies. View full abstract»

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  • Input Balun Embedded Low-Noise Amplifier With a Differential Structure

    Page(s): 403 - 405
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    In this study, we designed a 5 GHz low-noise amplifier (LNA) with a differential structure using 0.18 μm RFCMOS technology. An input balun is embedded into the LNA to enhance the gain, minimize the noise figure (NF), and miniaturize the overall chip size. The NF is minimized because the loss induced by the passive balun is removed. The first stage of the designed LNA performs the activities of the input balun and serves as the gain stage. To verify the feasibility of the proposed input-balun-embedded amplifier, we designed a typical LNA and the proposed LNA. We obtained a 29.4 dB gain with a NF of 1.85 dB. The measured dc power consumption is approximately 27 mW. The chip size is 1.0×0.74 mm2. From the measured results of the typical and proposed LNAs, we successfully prove the feasibility of the proposed method to minimize the NF and enhance the gain. View full abstract»

    Open Access
  • A CMOS Envelope-Tracking Transmitter With an On-Chip Common-Gate Voltage Modulation Linearizer

    Page(s): 406 - 408
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (763 KB) |  | HTML iconHTML  

    This letter presents a fully integrated CMOS envelope-tracking transmitter with an on-chip common-gate voltage modulation linearizer that achieves an average output power of 26/23.5 dBm with a PAE of 33/28%, an ACLR of -33 / -32.5 dBc at a frequency of 1.9 GHz for 3.84 MHz BW 3.5 dB PAPR WCDMA and 5 MHz BW 7.5 dB PAPR LTE signals in an 0.18-μm CMOS process. The CMOS ET transmitter is integrated with an envelope amplifier, two pairs of saturated power amplifiers, and an on-chip linearizer. The total chip size is 2.5 × 1.5 mm2 with the input/output on-chip transformers and matching networks. View full abstract»

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  • Dual-Band GaN MMIC Power Amplifier for Microwave Backhaul Applications

    Page(s): 409 - 411
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (593 KB) |  | HTML iconHTML  

    Design and characterization of a dual-band (7 GHz and 15 GHz) MMIC GaN linear Power Amplifier are presented. The amplifier, suitable for point-to-point microwave backhaul applications, exploits a TriQuint GaN foundry process. Large signal measurements exhibit power gain higher than 10 dB and 7 dB in the lower and higher bands respectively, and saturated output power of 34.7 dBm, in a 15% band around the two center frequencies. View full abstract»

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  • Low Phase Noise GaN HEMT Oscillators With Excellent Figures of Merit

    Page(s): 412 - 414
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (863 KB) |  | HTML iconHTML  

    This letter presents guidelines for the design of low phase noise oscillators in GaN high electron mobility transistor (HEMT) technology. The design starts from bias-dependent low-frequency (LF) noise measurements. Oscillator topology and bias point are then chosen for operation in regions where LF noise is low. The best LF noise properties are obtained for low drain voltage and current. Thus, the low phase noise can be achieved at low dc power which also means that power normalized phase noise figure of merit (FOM) will be good. Two different oscillators have been designed and measured. A 9.9 GHz common-gate balanced Colpitts oscillator operating in class C presents a phase noise of -136 dBc/Hz@1 MHz. The result is achieved for Vd =6 V and Id = 30 mA, giving FOM = 193 dBc/Hz. A 1.95 GHz negative-resistance oscillator operating in switched mode presents a phase noise of of -149 dBc/Hz@ 1 MHz offset. With drain voltage and current of Vd = 4 V and Id = 100 mA, this oscillator presents FOM = 189 dBc/Hz. To the best of the author's knowledge, these two oscillators present the highest reported FOM for GaN HEMT oscillators. View full abstract»

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  • Absorptive Limiter for Frequency-Selective Circuits

    Page(s): 415 - 417
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (433 KB) |  | HTML iconHTML  

    This letter describes a novel absorptive limiter for frequency-selective circuits. The proposed circuit allows the design of absorptive limiters based on a bi-state phase shifter, which is appropriate for integration into channelizing devices, such as hybrid-coupled input multiplexers. A preliminary prototype with shunt PIN diodes has been fabricated and measured to demonstrate the viability of the concept. View full abstract»

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  • G_{m} -Boosted Complementary Current-Reuse Colpitts VCO With Low Power and Low Phase Noise

    Page(s): 418 - 420
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (790 KB) |  | HTML iconHTML  

    In this letter, a transformer-based current-reuse Colpitts voltage controlled oscillator (VCO) is proposed, which combines a N-type and P-type Colpitts oscillators using a 5-port transformer in a complementary form to provide the differential outputs. The proposed VCO has low phase noise due to the low noise Colpitts oscillator topology and the negative-Gm boosting technique with half of the DC-current consumption using the current-reusing method. The proposed VCO has the frequency tuning range from 8.57 to 10.21 GHz, and shows low phase noise of -110.6 dBc/Hz at 1 MHz offset frequency at 9.41 GHz and high figure of merit with tuning range (FoMT) of -191.8 dBc/Hz. The power consumption is 2.1 mW from 1.2 V supply voltage. The VCO is implemented using 0.13 μm CMOS process with chip area of 0.45 mm2. View full abstract»

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  • A Graphical Aid for the Complex Permittivity Measurement at Microwave and Millimeter Wavelengths

    Page(s): 421 - 423
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB) |  | HTML iconHTML  

    We introduce a novel procedure to retrieve the complex permittivity ϵ'-jϵ'' of dielectric materials. It is a variant of the well-known waveguide method, and uses as input the one-port reflection data from a vector network analyzer connected to a short-circuited rectangular waveguide filled with a dielectric sample of known length. Here, it is shown that for low to moderate loss materials, the locus of the reflection coefficient in the complex plane versus frequency is approximately a circumference arc with curvature radius that depends mainly on ϵ'' and such that the swept angle depends mostly on ϵ'. It is proven that fitting the theoretical circumference arc with the measured data not only allows identifying possible measurement errors but also enables estimating the complex permittivity with good accuracy. A graphical based implementation of the method is described and validated experimentally. View full abstract»

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  • 500 MHz OOK Transmitter With 22 pj/bit, 38.4% Efficiency Using RF Current Combining

    Page(s): 424 - 426
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB) |  | HTML iconHTML  

    A 500 MHz On-Off Keying (OOK) transmitter integrated with a high-efficiency wideband power amplifier (PA) is designed for low-power/high-data rate applications. The PA biased in Class C region, employs a bias current-reused and an RF current-combining structure to achieve a high-efficiency and high-data rate. The transmitter is fabricated using a 0.13 μm CMOS process. The chip size is 0.6 mm2 and the measured drain efficiency of the PA reaches 59.5% at 500 MHz with 1.62 dBm output power while consuming only 2.52 mW dc power from a 3 V power supply. The efficiency of the transmitter is 38.4% and the energy usage is 22 pJ/bit at a data rate of 100 Mbps with -0.75 dBm average output power. View full abstract»

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  • SU-8 2000 Millimeter Wave Material Characterization

    Page(s): 427 - 429
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (415 KB) |  | HTML iconHTML  

    SU-8 2000 is an epoxy based photoresist widely used in the fabrication of MEMS for its thick film capability. SU-8 also holds promise as a low cost material for millimeter wave packaging and devices where thick films are required. This letter investigates the electrical material properties of SU-8 2000 at frequencies beyond 140 GHz. Characterization using microstrip ring and T resonators reveal a dielectric constant of 3.0 across the entire band with an approximate loss tangent of 0.04. 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