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Microwave Theory and Techniques, IEEE Transactions on

Issue 11  Part 1 • Date Nov. 2010

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Displaying Results 1 - 25 of 33
  • Table of contents

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

    Page(s): C2
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  • A Millimeter-Wave (24/31-GHz) Dual-Band Switchable Harmonic Receiver in 0.18- \mu m SiGe Process

    Page(s): 2717 - 2730
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    A dual-band switchable harmonic receiver for downconverting the industrial-scientific-medical and local-multipoint-distribution-service bands at 24 and 31 GHz is proposed in this paper. The front end utilizes a new technique for band selection. Mathematical formulation, including the effect of mismatches, for the new switchable harmonic receiver is provided in this paper. In addition, new circuit techniques for the low-noise amplifier and millimeter-wave mixer implementations are presented. The receiver is implemented using 0.18-μm BiCMOS technology with a total power consumption of 60 mW. Measurements show a band rejection higher than 43 dB, gain of 21 and 18 dB, NF lower than 8 and 9.5 dB, and third-order intercept point of -18 and -17 dBm for the 24- and 31-GHz frequency bands, respectively. View full abstract»

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  • A 20–32-GHz Wideband Mixer With 12-GHz IF bandwidth in 0.18- \mu{\hbox {m}} SiGe Process

    Page(s): 2731 - 2740
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    This paper presents a 20-32-GHz wideband BiCMOS mixer with an IF bandwidth of 12 GHz. The mixer utilizes an inductive peaking technique to extend the bandwidth of the downconverted IF signal. To our knowledge, the proposed mixer achieves the widest IF bandwidth using silicon-based technologies in K-band. Analytical expressions for the conversion gain and output noise of the proposed mixer are presented. The wideband mixer is implemented using 0.18-μm BiCMOS technology and occupies an area of 0.19 mm2. It achieves a conversion gain of 3 dB, a noise figure between 10.5 and 13.0 dB, and an IIP3 higher than 0.5 dBm with a power consumption of 18 mW from a 1.8-V supply. View full abstract»

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  • Parasitic Compensation Design Technique for a C-Band GaN HEMT Class-F Amplifier

    Page(s): 2741 - 2750
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    A class-F/inverse class-F load circuit design method that includes parasitic elements such as drain-source capacitance and bonding wire inductance has been developed. For the class-F load circuit design, a reactance function which has zeros at even harmonic frequencies and poles at odd harmonic frequencies is expanded to an -ladder circuit including parasitic elements through the use of the second Cauer canonical form. For the inverse class-F load circuit design, the zero points and the poles are exchanged. One stage of the -ladder circuit can be approximately replaced to a distributed circuit element for higher frequency operation. The proposed method allows parasitic compensation up to an arbitrary harmonic order by adding zeros and poles. Additionally, if distributed circuit elements are used, the method also compensates frequency dispersive characteristics of microstrip lines. According to the proposed method, a class-F amplifier using an AlGaN-GaN HEMT has been fabricated at 5.8 GHz. The fabricated class-F amplifier delivered high efficiency characteristics, with a maximum drain efficiency of 79.9%, a maximum power-added efficiency (PAE) of 71.4%, and an output power of up to 33.4 dBm at 5.86 GHz. View full abstract»

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  • A 5.8 GHz Integrated CMOS Dedicated Short Range Communication Transceiver for the Korea/Japan Electronic Toll Collection System

    Page(s): 2751 - 2763
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    In this paper, a RF front-end of the 5.8 GHz integrated CMOS dedicated short range communication (DSRC) transceiver for the Korea/Japan electronic toll collection system is presented. The receiver uses low-IF conversion architecture for high sensitivity and low-power consumption while the transmitter uses direct up-conversion architecture for its simple structure and reliability. To solve image problem in the low-IF receiver, 10 MHz IF and 40 MHz IF are chosen for Korean and Japanese DSRC standards, respectively, since they make no image signals exist in image band. A single-quadrature mixer with the proposed transconductor-type quadrature generator in RF signal path is also adopted which has accurate quadrature characteristic in 5.8 GHz frequency. When the RF front-end of the integrated 5.8 GHz DSRC transceiver is implemented using 0.13 μm CMOS technology, the receiver achieves the overall noise figure of less than 5 dB with image rejection ratio of more than 30 dB, and the transmitter carries an output peak power of 10 dBm with the adjacent channel power ratio of -43 dBc. The RF front-end of the 5.8 GHz DSRC transceiver dissipates 45 mA with 1.2 V supply voltage and 142 mA with 1.2/3.3 V dual supply voltage during RXand TX-modes, respectively. View full abstract»

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  • Adaptive Input-Power Distribution in Doherty Power Amplifiers for Linearity and Efficiency Enhancement

    Page(s): 2764 - 2771
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    A new technique based on an adaptive input-power distribution is introduced to overcome the limitations of practical Doherty power amplifiers. The proposed Doherty amplifier employs an extended-resonance power-divider at its input. By taking advantage of the auxiliary cell's nonlinear input impedance, the extended-resonance divider is designed such that it provides a proper power-dependent power-division between the main and auxiliary cells. Therefore, the two cells are efficiently driven and can generate output current and voltage characteristics similar to the ideal Doherty amplifier, resulting in both linearity and efficiency improvements. The performance of the new Doherty amplifier is compared with a conventional design through simulations and measurements. The proposed Doherty amplifier achieves a measured ACLR improvement of 5-7 dB over a wide range of output power levels, as well as an increased power-added-efficiency of up to 5% for WCDMA signals. The proposed Doherty design does not require complex circuitry and yields a compact circuit. View full abstract»

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  • Linearly Polarized Modes of a Corrugated Metallic Waveguide

    Page(s): 2772 - 2780
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    A linearly polarized (LPmn) mode basis set for oversized, corrugated, metallic waveguides is derived for the special case of quarter-wavelength-depth circumferential corrugations. The relationship between the LPmn modes and the conventional modes (HEmn, EHmn, TE0n, TM0n) of the corrugated guide is shown. The loss in a gap or equivalent miter bend in the waveguide is calculated for single-mode and multimode propagation on the line. In the latter case, it is shown that modes of the same symmetry interfere with one another, causing enhanced or reduced loss, depending on the relative phase of the modes. If two modes with azimuthal (m) indexes that differ by one propagate in the waveguide, the resultant centroid and the tilt angle of radiation at the guide end are shown to be related through a constant of the motion. These results describe the propagation of high-power linearly polarized radiation in overmoded corrugated waveguides. View full abstract»

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  • Arbitrary Electromagnetic Conductor Boundaries Using Faraday Rotation in a Grounded Ferrite Slab

    Page(s): 2781 - 2793
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    The realization of arbitrary perfect electromagnetic conductor boundaries by a grounded ferrite slab using Faraday rotation is proposed. This is the first practical realization of a perfect electromagnetic conductor boundary to the authors' knowledge. The key principle of the grounded ferrite perfect electromagnetic conductor boundary is the combination of Faraday rotation and reflection from the perfect electric conductor of the ground plane. From this combined effect, arbitrary angles between the incident and reflected fields can be obtained at the surface of the slab, so as to achieve arbitrary perfect electromagnetic conductor conditions by superposition with the incident field. An exact electromagnetic analysis of the structure is performed based on the generalized scattering matrix method and an in-depth description of its operation phenomenology is provided. As an illustration, a tunable transverse electromagnetic (TEM) waveguide with grounded ferrite PMC lateral walls is demonstrated experimentally. Due to its flexibility in the control of the polarization of the reflected field, the proposed grounded ferrite perfect electromagnetic conductor may find applications in various types of reflectors and polarization-based radio frequency identifiers. View full abstract»

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  • Greatly Enhanced Permeability and Expanded Bandwidth for Spinel Ferrite Composites With Flaky Fillers

    Page(s): 2794 - 2799
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    Spinel ferrite flakes are prepared for use as fillers in electromagnetic (EM) composites. EM attenuation composites with the flaky fillers exhibit greatly enhanced high-frequency magnetic properties and attenuation properties. The complex permeability, μ'r,o and μ"r,max, is enhanced by above 300%, and the relative attenuation bandwidth Wp is increased by 40%, as compared to those for composites with conventional spherical fillers. Wp achieves 80% of the theoretical maximum relative bandwidth. The composites with the flaky fillers are powerful and potential candidates as EM attenuation materials with broad bandwidth at microwave frequency. View full abstract»

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  • Investigation of a Class-J Power Amplifier With a Nonlinear C_{\rm out} for Optimized Operation

    Page(s): 2800 - 2811
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    This paper presents the operation principle of Class-J power amplifiers (PAs) with linear and nonlinear output capacitors (Couts). The efficiency of a Class-J amplifier is enhanced by the nonlinear capacitance because of the harmonic generation from the nonlinear Cout, especially the second-harmonic voltage component. This harmonic voltage allows the reduction of the phase difference between the fundamental voltage and current components from 45° to less than 45° while maintaining a half-sinusoidal shape. Therefore, a Class-J amplifier with the nonlinear Cout can deliver larger output power and higher efficiency than with a linear Cout. As a further optimized structure of the Class-J amplifier, the saturated PA, a recently-reported amplifier in our group, is presented. The phase difference of the proposed PA is zero. Like the Class-J amplifier, the PA uses a nonlinear Cout to shape the voltage waveform with a purely resistive fundamental load impedance at the current source, which enhances the output power and efficiency. The PA is favorably compared to the Class-J amplifier in terms of the waveform, load impedance, output power, and efficiency. These operations are described using both the ideal and real models of the transistor in Agilent Advanced Design System. A highly efficient amplifier based on the saturated PA is designed by using a Cree GaN HEMT CGH40010 device at 2.14 GHz. It provides a power-added efficiency of 77.3% at a saturated power of 40.6 dBm (11.5 W). View full abstract»

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  • Accurate Power Efficiency Estimation of GHz Wireless Delta-Sigma Transmitters for Different Classes of Switching Mode Power Amplifiers

    Page(s): 2812 - 2819
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    This paper proposes a new closed-form expression for computing the power efficiency of delta-sigma (DS) radio frequency (RF) transmitters. Due to the large bandwidth of the pulsewidth modulated (PWM) signal at the output of the DS modulator, the peak efficiency of the power amplifier (PA) when driven by a PWM signal is considerably different than its peak efficiency when the input signal is a continuous sine wave. A weight averaging of the efficiency over the frequency bandwidth of the PWM signal is considered for accurate estimation and prediction of the power efficiency of DS RF transmitters. It is shown that, for a low-pass DS transmitter, the overall average power efficiency of the DS transmitter can be accurately estimated by the product of the modulated peak efficiency of the PA and the coding efficiency of the modulator. For bandpass DS transmitters, an additional parameter that accounts for the duty cycle effect on the efficiency of switching-mode PAs has to be considered. To validate the new proposed expression, a DS transmitter for WiMAX, CDMA and EDGE standards is designed, prototyped and tested. The comparison of the simulated and measured efficiencies of the DS transmitter proves the validity and accuracy of the proposed expression. View full abstract»

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  • Design of Highly Efficient Load Modulation Transmitter for Wideband Cellular Applications

    Page(s): 2820 - 2828
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    In this paper, the high potential of varactor-based dynamic load modulation (DLM) techniques for wideband cellular applications is demonstrated. A systematic design procedure is proposed to ensure high-efficiency wideband performance. It incorporates harmonically tuned power amplifier (PA) concepts and tunable matching techniques in an integrated design. A DLM transmitter at 2.65 GHz with a peak output power of 6 W is designed using the proposed procedure. In order to investigate the wideband performance of the implemented demonstrator, WCDMA signals with scaled bandwidths are employed. The signal peak-to-average ratio is 7 dB and the same for all the experiments. For the 38.4-MHz signal, which has a corresponding channel bandwidth of > 40 MHz, an average power added-efficiency (PAE) of 44%, normalized mean square error (NMSE) of -35 dB, and adjacent channel leakage ratio (ACLR) of -43 dBc are measured. View full abstract»

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  • Shape-Preserving Response Prediction for Microwave Design Optimization

    Page(s): 2829 - 2837
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (547 KB) |  | HTML iconHTML  

    A shape-preserving response prediction methodology for microwave design optimization is introduced. The presented technique allows us to estimate the response of the microwave structure being optimized (fine model) using a computationally cheap representation of the structure (coarse model). The change of the coarse model response is described by the translation vectors corresponding to certain (finite) number of characteristic points of the response. These translation vectors are subsequently used to predict the response change of the fine model. The presented method has very good generalization capability and it is not based on any extractable parameters, which makes it easy to implement. Applications for microwave design optimization are discussed. The robustness of the proposed approach is demonstrated by extensive comparison with space mapping, which is one of the most efficient optimization approaches in microwave engineering so far. View full abstract»

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  • On the Design of Pulsed Sources and Spread Compensation in Finite-Difference Time-Domain Electromagnetic Simulations

    Page(s): 2838 - 2849
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    This paper first describes the phenomenon of Gaussian pulse spread due to numerical dispersion in the finite-difference time-domain (FDTD) method for electromagnetic computation. This effect is undesired, as it reduces the precision with which multipath pulses can be resolved in the time domain. The quantification of the pulse spread is thus useful to evaluate the accuracy of pulsed FDTD simulations. Then, using a linear approximation to the numerical phase delay, a formula to predict the pulse duration is developed. Later, this formula is used to design a Gaussian source that keeps the spread of numerical pulses bounded in wideband FDTD. Finally, the developed model and the approximation are validated via simulations. View full abstract»

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  • Extraction of Equivalent Network of Arbitrarily Shaped Power-Ground Planes With Narrow Slots Using a Novel Integral Equation Method

    Page(s): 2850 - 2855
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    A novel integral equation method for efficient and accurate modeling of power-ground planes with narrow slots is provided in this paper. The equivalence principle is used to extend finite-size power-ground planes to infinite parallel planes. The discontinuities in the original power-ground planes, including the slot, via clearance, and boundary, are represented by equivalent electric and magnetic currents. Coupled integral equations are created for these equivalent currents. By making use of the modal field distribution between the power and ground planes, the complex surface integrals are reduced to simple one-dimensional line integrals. This greatly reduces the computing time while good accuracy is preserved. Thereafter, the paths of integration are discretized into many segments, which are equivalent to network ports, such that an equivalent microwave network of the power-ground planes with slots is derived through the solution of the integral equations. This equivalent network is used for power integrity analysis. By comparing the proposed method with measurement results and available full-wave methods, its accuracy and efficiency are verified. View full abstract»

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  • Preconditioned Second-Order Multi-Point Passive Model Reduction for Electromagnetic Simulations

    Page(s): 2856 - 2866
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    A second-order multi-point Krylov subspace projection based model order reduction process for electromagnetic simulations is presented. The electromagnetic setup is converted to a second-order model-susceptance element based equivalent circuit. The state-space representation of this equivalent circuit is suitably reduced through a model order reduction process, where the recursive calculation of the projection matrix is done through a preconditioned iterative method. Issues concerning the passivity of the reduced system are discussed. The single-point and multi-point schemes are validated through numerical examples. The second-order multi-point algorithm for the reduction process is shown to be advantageous in matching response curves exhibiting complex behavior. View full abstract»

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  • Design of Triple-Mode Ring Resonator for Wideband Microstrip Bandpass Filters

    Page(s): 2867 - 2877
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    A triple-mode microstrip ring resonator core for the design of bandpass filters is proposed in this paper. It is a modification of the conventional single-mode ring resonator with a pair of open-ended coupled lines and a shunt open stub for a transmission-line path of the ring substituted to form a triple-mode resonator. Since the triple-mode resonator possesses three resonances, one at the center frequency and the other two near the edges of the passband, a flat passband response can be achieved when it is employed to implement a bandpass filter. The resonator also exhibits attenuation poles close to the edges of the passband, thereby offering sharp rejection in the bandpass filter response. Moreover, since the signal applied at the input port is effectively forced to travel mainly through the transmission line path over the passband frequency, the loss incurred by the coupled lines is minimized. Extensive theoretical analysis of the triple-mode ring and design example of the bandpass filter prototypes based on the ring structure are given. The prototype filters's performance is validated through both simulations and experiments, where good agreement with the theoretical prediction is observed. View full abstract»

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  • Analysis and Design of Single-to-Balanced Combline Bandpass Filters With Two Independently Controllable Transmission Zeros in LTCC Technology

    Page(s): 2878 - 2887
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    In this paper, the analysis and design of single-to-balanced combline bandpass filter are presented. The cross-coupled effect is introduced to create two transmission zeros that can be located independently in either the upper or lower stopband. Notably, the effect of nonadjacent line coupling on the filter response is properly addressed, and an efficient way to compensate it is proposed. Also, the issue of a frequency-dependent J-inverter in bandpass filter design is also well treated. The proposed filter can be implemented using the low-temperature co-fired ceramic (LTCC) process to achieve very compact circuit size, in which the combline line lengths are as small as . Specifically, two third-order single-to-balanced combline bandpass filters in LTCC are implemented. Good balance performance, low loss, good selectivity, and compact size are achieved. View full abstract»

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  • Design of Compact Dual-Mode Microstrip Filters

    Page(s): 2888 - 2895
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    This paper presents a novel filter design technique for the compact microstrip dual-mode filters. An equivalent circuit for the single dual-mode filter section is derived to show that a single unit behaves as a pair of coupled synchronously tuned single-mode resonators. The equivalent circuit was linked to the inverter-coupled bandpass prototype network to allow higher order filters to be realized. A complete design example (from design to realization) of a fourth-order Chebyshev bandpass filter is presented. It is shown that the dual-mode resonator may be employed to design cross-coupled filters with finite frequency zeros. Two filters are designed using optimized coupling matrix method, fabricated and tested. Experimental and simulation results are presented to validate the argument. Finally, it is shown that more compactness may be achieved with narrowband filters by employing folded resonators. View full abstract»

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  • Super Compact Low-Temperature Co-Fired Ceramic Bandpass Filters Using the Hybrid Resonator

    Page(s): 2896 - 2907
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1193 KB) |  | HTML iconHTML  

    A novel low-temperature co-fired ceramic (LTCC) resonator is proposed based on the hybrid resonant circuits. The resonator exhibits a very compact size and is also able to introduce a transmission zero in the filter design. A super compact bandpass filter with high performance was designed at the center frequency of 2.45 GHz and fabricated using the proposed LTCC hybrid resonator. This filter has a very compact size of 0.9 mm 0.688 mm 0.652 mm and exhibits a low insertion loss of less than 1.2 dB in the passband. Moreover, the transmission zero that is located at 4.5 GHz efficiently suppresses the spurious responses. In order to improve the stopband suppression even more, the revised resonator is used for the second filter design. Besides occupying an even smaller volume of 0.76 mm 0.748 mm0.67 mm, the second filter exhibits a wide stopband suppression higher than 35 dB from 3.4 to 8 GHz. In addition to the super compact size and wide stopband suppression, insertion losses of less than 2.5 dB were achieved in the passband. A transmission zero at 5.8 GHz was also achieved. View full abstract»

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  • Micro-Coaxial Impedance Transformers

    Page(s): 2908 - 2914
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    This paper demonstrates two broadband air-filled micro-coaxial 4:1 (2-24 GHz) and 2.25:1 (2-22 GHz) impedance transformers. The 4:1 transformer converts 50 to 12.5 Ω and the 2.25:1 device transforms 50 to 22.22 Ω. The circuits are fabricated on silicon with PolyStrata technology, and are implemented with 650 μm × 400 μm air-filled micro-coaxial lines. Back-to-back circuits and single structures with geometrical tapers are designed for systematic characterization. Simulation and measurement results are in excellent agreement. The return loss for both transformers is better than 15 dB over the design bandwidth. View full abstract»

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  • Compact Planar Magic-T Based on the Double-Sided Parallel-Strip Line and the Slotline Coupling

    Page(s): 2915 - 2923
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    Two compact planar magic-T structures implemented on the double-sided parallel-strip line (DSPSL) and the slotline coupling are proposed and demonstrated. Due to a metallic ground inserted into the middle of the substrate for the double-sided parallel-strip line, the E-plane DSPSL power divider thus shows an intrinsic 180° out-of-phase characteristic between the two input/ output ports. A transition between slotline and DSPSL is utilized to realize the H-plane input/output port of the magic-T. The equivalent circuits are derived for the design of the proposed planar multilayer magic-T. Good agreement between the measured and simulated results indicates that the fractional bandwidths for the two planar magic-T structures are 42.8% and 43.8%, respectively, while the amplitude and phase imbalance are less than 0.22 dB and 1.5°. View full abstract»

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  • Miniaturized Quasi-Lumped Coupled-Line Single-Section and Multisection Directional Couplers

    Page(s): 2924 - 2931
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    A class of lumped-element coupled-line directional couplers has been investigated. The paper discusses the influence of the number of coupler's subsections on the overall couplers' performance. The design procedure for calculating elements of the coupler for the chosen coupling C and the number of coupler's subsections has been proposed. The design procedure has been experimentally verified by the measurements of a single-section directional coupler. Also, an asymmetric two-section coupler not reported in the literature has been designed using a lumped-element technique, and the experimental results are shown. View full abstract»

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  • Design of Compact 90 ^{\circ} and 180 ^{\circ} Couplers With Harmonic Suppression Using Lumped-Element Bandstop Resonators

    Page(s): 2932 - 2939
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    Compact 3-dB 90° and 180° couplers with harmonic suppression using lumped-element bandstop resonators are proposed. The bandstop resonators are not only used to provide the high-pass and low-pass characteristics of conventional couplers, but also have a significant harmonic band rejection at the same time. Therefore, the required lumped-element inductors with a low quality factor are reduced as much as possible, enabling significant circuit size reduction. Further, minimum bulky via holes are employed in these topologies, thus carrying them out on the monolithic microwave integrated circuit is beneficial. Detailed design and theoretical analysis are presented for the proposed couplers with harmonic rejection. To validate the design concept, two proposed couplers implemented on an FR-4 printed circuit board at 2.45 GHz are demonstrated. Promising agreements between the simulation and measurement can be observed. Experimental results reveal that the 90° and 180° couplers suppressed the second harmonic below 26 and 30 dB, respectively, within the 0.6-dB amplitude imbalance and 2° phase error at the center frequency. View full abstract»

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The IEEE Transactions on Microwave Theory and Techniques focuses on that part of engineering and theory associated with microwave/millimeter-wave components, devices, circuits, and systems involving the generation, modulation, demodulation, control, transmission, and detection of microwave signals. This includes scientific, technical, and industrial, activities. Microwave theory and techniques relates to electromagnetic waves usually in the frequency region between a few MHz and a THz; other spectral regions and wave types are included within the scope of the Society whenever basic microwave theory and techniques can yield useful results. Generally, this occurs in the theory of wave propagation in structures with dimensions comparable to a wavelength, and in the related techniques for analysis and design..

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