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Microwave Theory and Techniques, IEEE Transactions on

Issue 6 • Date June 2003

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Displaying Results 1 - 21 of 21
  • Inline TM110-mode filters with high-design flexibility by utilizing bypass couplings of nonresonating TE1001/ modes

    Page(s): 1735 - 1742
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1346 KB) |  | HTML iconHTML  

    This paper presents a new class of pseudoelliptic function filters that are based on compact inline TM110-mode cavity configurations. No structural folding is required. The bypass couplings are implemented through the nonresonating TE1001/ modes so that arbitrarily positioned transmission zeros can be implemented. Design guidelines to generate a given transmission zero on the desired side of the passband and how to control it are presented. To demonstrate its flexibility, the approach is illustrated at examples of four-pole inline filters providing Chebyshev, elliptic-function-type, and asymmetric characteristics. Performance comparisons with different numerical codes validate the designs. A fourth-order pseudoelliptic filter with four transmission zeros is then designed, constructed, and measured. Excellent agreement between simulated and experimental results verifies the approach. View full abstract»

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  • Cryogenic wide-band ultra-low-noise IF amplifiers operating at ultra-low DC power

    Page(s): 1705 - 1711
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (477 KB) |  | HTML iconHTML  

    This paper describes cryogenic broad-band amplifiers with very low power consumption and very low noise for the 4-8-GHz frequency range. At room temperature, the two-stage InP-based amplifier has a gain of 27 dB and a noise temperature of 31 K with a power consumption of 14.4 mW per stage, including bias circuitry. When cooled to 15 K, an input noise temperature of 1.4 K is obtained at 5.7 mW per stage. At 0.51 mW per stage, the input noise increases to 2.4 K. The noise measurements have been repeated at different laboratories using different methods and are found consistent. View full abstract»

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  • Silicon-based reconfigurable antennas-concepts, analysis, implementation, and feasibility

    Page(s): 1650 - 1661
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1396 KB) |  | HTML iconHTML  

    We report on an innovative reconfigurable antenna concept with significant practical relevance based on the dynamic definition of metal-like conductive plasma channels in high-resistivity silicon that are activated by the injection of DC current. The plasma channels are precisely formed and addressed using current high-resolution silicon fabrication technology. These dynamically defined plasma-reconfigurable antennas enable frequency hopping, beam shaping, and steering without the complexity of RF feed structures. This concept shows promise for delivering the performance and capabilities of a phased array, but at a reduced cost. However, challenges such as p-i-n biasing circuit complexity and their nonlinearities, as well as antenna efficiency, would still require further investigations. View full abstract»

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  • The class-E/F family of ZVS switching amplifiers

    Page(s): 1677 - 1690
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (767 KB) |  | HTML iconHTML  

    A new family of switching amplifiers, each member having some of the features of both class E and inverse F, is introduced. These class-E/F amplifiers have class-E features such as incorporation of the transistor parasitic capacitance into the circuit, exact truly switching time-domain solutions, and allowance for zero-voltage-switching operation. Additionally, some number of harmonics may be tuned in the fashion of inverse class F in order to achieve more desirable voltage and current waveforms for improved performance. Operational waveforms for several implementations are presented, and efficiency estimates are compared to class-E. View full abstract»

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  • Class-EM switching-mode tuned power amplifier-high efficiency with slow-switching transistor

    Page(s): 1662 - 1676
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (615 KB) |  | HTML iconHTML  

    In class-E switching-mode power amplifiers, the switch-current waveform includes a step change ("jump"), approximated by a ramp of <15% of the period. At a transistor's highest useful frequency, the large input drive required for fast-enough switching yields marginal power gain. Objective: a high-efficiency power amplifier with jumpless current and voltage waveforms. Previously, that was proven impossible for amplifiers using only linear passive components and an ideal switch. We present the theory of a new topology that does achieve the objective: a class-E amplifier with nonlinear passive or active components in the load network. A "biharmonic" version was simulated, built, and tested. It comprises a main stage switching at the output frequency f1, drawing DC power of approximately 3/4(POUT RF/drain efficiency), and an auxiliary amplifier switching at 2f1, injecting 2f1-current into the circuit node at the main-stage transistor's output port to shape jumpless voltage and current waveforms. That switching (nonlinear) output port converts 2f1 power from the auxiliary amplifier to approximately 1/4 of the f1 power at the load. Computer simulation, and measurement on a scaled-frequency 3.5-MHz prototype, show that switching losses practically disappear when the main-stage switch is operated in the jumpless regime. View full abstract»

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  • Novel coupled-line conductor-backed coplanar and microstrip directional couplers for PCB and LTCC applications

    Page(s): 1743 - 1751
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (706 KB) |  | HTML iconHTML  

    Novel coupled-line conductor-backed coplanar and microstrip directional couplers, convenient for manufacturing in standard printed circuit board (PCB) or low-temperature co-fired ceramic (LTCC) technology, are proposed. The coplanar coupler, consisting of a layered structure with four strips and covering a -10 to -2.6 dB coupling coefficient, is theoretically ideally impedance matched and perfectly isolated at all frequencies under the assumption of validity of quasi-static approximation and two-mode propagation. The microstrip coupler, a modification of the coplanar one, can be ideally compensated only in an area of strong coupling coefficients. The novel couplers are not sensitive to lateral misalignment of conductive layers, and not sensitive to thickness and dielectric permittivity tolerances of applied dielectric substrates. Preliminary experimental results for 2.7-, 3-, and 8.34-dB couplers, designed both in PCB, as well as LTCC technology are presented. View full abstract»

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  • A new configuration of polarization-rotating dual-beam interferometer for space use

    Page(s): 1696 - 1704
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (562 KB) |  | HTML iconHTML  

    This paper presents a new configuration of quasi-optical polarization-rotating dual-beam interferometer, which uses a pair of frequency-selective polarizers (FSPs) consisting of a wire-grid placed in front of a flat mirror, and has a function similar to the conventional Martin-Puplett interferometer (MPI). Advantages of this new configuration over the conventional MPI are lower residual reflection at the input and output ports and suitability to fixed-tuned applications. An experiment has shown it to have an MPI-like frequency characteristic as calculated. Careful machining was successful in achieving accuracy needed for a specified filter characteristic. This FSP-based quasi-optical device is to be used as a sideband separator in a space-borne submillimeter receiver for atmospheric research. View full abstract»

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  • 50 years of RF and microwave sampling

    Page(s): 1787 - 1805
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1500 KB) |  | HTML iconHTML  

    Measurement of microwave and UHF signals is often done with sampling techniques. In this paper, the techniques and technology of sampling of electrical signals is reviewed from 1950 to the present. It includes both references to the open literature, as well as an extensive review of relevant patents. It also provides an overview of sampling applications and the use of computer technology to compensate and correct for errors in the sampling process. View full abstract»

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  • A displacement measurement technique using millimeter-wave interferometry

    Page(s): 1724 - 1728
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (397 KB) |  | HTML iconHTML  

    A displacement measurement sensor, capable of sub-millimeter resolution, using millimeter-wave interferometry has been developed. The sensor operates at 37.6 GHz and is realized using both microwave integrated circuits and monolithic microwave integrated circuits. It has been used to accurately measure the displacement of metal plate location and water level. A resolution of only 0.05 mm is achieved. A maximum error of 0.3 mm is also attained without correction for the nonlinearity of the phase-detection processor and agrees well with the theoretical calculation. View full abstract»

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  • The epHEMT gate at microwave frequencies

    Page(s): 1718 - 1723
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (549 KB) |  | HTML iconHTML  

    This paper examines the high-frequency behavior of the enhancement-mode pseudomorphic high electron-mobility transistor (epHEMT) gate. During this study, no bias was applied between the drain and source. Rather, the gate was forward biased with either the drain, source, or channel (drain and source connected together) grounded. While applying positive voltage Vg to the gate, one-port S-parameters were measured from 0.1 to 10 GHz and then converted to Z-parameters. Plotting the real part R of the impedance reveals two sharp peaks. The first peak occurs near the device threshold voltage for conduction in the InGaAs well. A second peak occurs at higher voltages where conduction begins to occur in the surface AlGaAs layer. An equivalent-circuit model is proposed to account for the epHEMT gate's high-frequency behavior and the proposed model is shown to be in good agreement with the experimental data. View full abstract»

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  • Metallo-dielectric electromagnetic bandgap structures for suppression and isolation of the parallel-plate noise in high-speed circuits

    Page(s): 1629 - 1639
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (900 KB) |  | HTML iconHTML  

    A novel approach for the suppression of the parallel-plate waveguide (PPW) noise in high-speed printed circuit boards is presented. In this approach, one of the two conductors forming the PPW is replaced by an electromagnetic bandgap (EBG) surface. The main advantage of the proposed approach over the commonly practiced methods is the omnidirectional noise suppression it provides. For this purpose, two EBG structures are initially designed by utilizing an approximate circuit model. Subsequently, the corresponding band structures are characterized by analytical solutions using the transverse resonance method, as well as full-wave finite-element simulations. The designed EBG surfaces were fabricated and employed in a number of PPW test boards. The corresponding frequency-domain measurements exhibited bandgaps of approximately 2.21 and 3.35 GHz in the frequency range below 6 GHz. More importantly, suppression of the PPW noise by 53% was achieved based on time-domain reflectometry experiments, while maintaining the signal transmission quality within the required specifications for common signaling standards. View full abstract»

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  • A hybrid finite-element-modal-expansion method with a new type of curvilinear mapping for the analysis of microwave passive devices

    Page(s): 1712 - 1717
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (369 KB) |  | HTML iconHTML  

    A hybrid finite-element-modal-expansion procedure for the three-dimensional analysis of passive microwave devices exploiting higher order vector basis functions and an innovative class of curved elements is presented. If modal expansions on ports are not analytically known, they can be numerically obtained via a preliminary two-and-one-half-dimensional finite-element analysis; curved triangular and tetrahedrical elements are defined by a rational Bezier mapping, which provides a remarkable increase in accuracy and flexibility over the conventional polynomial mapping without a significant increase in computational burden. Numerical results are provided to illustrate the efficiency and feasibility of the proposed technique. View full abstract»

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  • On the accuracy of direct extraction of the heterojunction-bipolar-transistor equivalent-circuit model parameters Cπ, CBC, and RE

    Page(s): 1640 - 1649
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (557 KB) |  | HTML iconHTML  

    Several basic small-signal equivalent-circuit models for bipolar transistors lead to simple analytical expressions for the model parameters in terms of measured values. This paper investigates the accuracy of these expressions for real transistors by applying the direct extraction equations to more complicated small-signal models. The extraction of the base/collector capacitance, base/emitter capacitance, and emitter resistance are considered. Analytically derived trends are illustrated using measurements on small-area high-speed InP/GaAsSb/InP double heterojunction bipolar transistors. View full abstract»

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  • On-wafer noise-parameter measurements at W-band

    Page(s): 1621 - 1628
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (572 KB) |  | HTML iconHTML  

    A wide-band on-wafer noise-parameter measurement setup has been developed for W-band. The system is based on a cold-source method and uses a simple manual impedance tuner. In addition to noise parameters, S-parameters can be measured with the same setup. Using the developed system, noise parameters of an InP high electron-mobility transistor have been measured and results are shown in the 79-94-GHz frequency band. This is the first comprehensive report of noise-parameter measurements made on active devices at W-band. View full abstract»

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  • Reflection characteristics of a PML with a shallow corrugation

    Page(s): 1691 - 1695
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (339 KB) |  | HTML iconHTML  

    The constitutive characteristics of anisotropic materials can be exploited to construct absorbers that provide reflectionless interfaces for waves at arbitrary angles of incidence. In this paper, we investigate how a weak corrugation affects the reflectivity of the anisotropic perfectly matched absorber developed by Sacks et al. (1995) for a flat interface. To do so, we develop a Rayleigh method to calculate the fields diffracted at the periodically corrugated boundary of an anisotropic absorber with constant constitutive tensors, which correspond to a planar (Cartesian) perfectly matched layer. We present numerical results in the nondiffractive regime (where only a specularly reflected wave can propagate) for sinusoidal corrugations with different groove height-to-period ratios. Our results show that the reflectivity of the anisotropic absorber near normal incidence remains very low (less than 0.4% for a 10% modulation), whereas it changes dramatically near grazing incidences. View full abstract»

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  • Parameters extraction and modeling for planar spiral inductor on Si-SiO2 substrates by DDM for conformal modules

    Page(s): 1763 - 1766
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    In this paper, the domain decomposition method (DDM) for conformal modules is used to get simple analytic expressions for parameters of planar spiral inductors on Si-SiO2 substrates. The conductor and substrate losses are considered in the expressions. The quality factor of the spiral inductor is computed with a transmission-line mode and compared with previously published experimental results, showing that DDM model is accurate and efficient for modeling an on-chip spiral inductor on Si-SiO2 substrates. View full abstract»

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  • Nonlinear analysis tools for the optimized design of harmonic-injection dividers

    Page(s): 1752 - 1762
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB) |  | HTML iconHTML  

    New nonlinear analysis tools for harmonic-injection dividers are presented based on bifurcation concepts. The advantage of these tools is their application simplicity and efficiency, which has enabled their use for actual circuit design and optimization. The tools allow control over the divided frequency and output power and predict the variation of the synchronization bands versus the circuit element values, which facilitates design correction. They have been extended to the analysis and optimization of phase-locked harmonic-injection dividers, which contain a low-frequency feedback loop. The use of this loop, together with the accuracy of the analysis, has enabled the implementation of novel frequency-division functions, such as the division of variable order, versus a circuit parameter, or the division by fractional order. The output noise of the frequency dividers is analyzed through the conversion-matrix approach, studying the noise variation along the division bands. The new techniques have been applied to the design of a frequency divider by order 4 and 5, with 18-GHz input frequency, and excellent agreement with experimental results has been obtained. View full abstract»

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  • Rapidly converging spectral-domain analysis of rectangularly shielded layered microstrip lines

    Page(s): 1729 - 1734
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (537 KB)  

    A moment-method-oriented direct integral-equation technique is presented for the exact analysis of rectangularly shielded layered microstrip lines. This technique retains the simplicity of conventional moment methods while optimizing them by recasting all matrix elements into rapidly converging series. Filling up the matrix requires no numerical integration. The proposed algorithms yield highly accurate results both for the modal currents and propagation constants. View full abstract»

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  • Subcell FDTD modeling of electrically thin dispersive layers

    Page(s): 1774 - 1780
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (429 KB) |  | HTML iconHTML  

    A novel technique for treating electrically thin dispersive layers with the finite-difference time-domain (FDTD) method is introduced. The proposed model is based on the subcell technique, where the constitutive relations are locally averaged in the FDTD grid. The most significant feature of the proposed model is its ability to model rather complicated dispersive layers having multiple pole pairs. The model is validated with several numerical examples making comparison with the exact results. Both time- and frequency-domain validations are presented. View full abstract»

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  • On the sensitivity of coupled resonator filters without some direct couplings

    Page(s): 1767 - 1773
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (391 KB) |  | HTML iconHTML  

    This paper presents an analysis of the sensitivity of coupled resonator filters in which some direct couplings are missing. The effect of changes in the coupling coefficients and resonant frequencies of the resonators is investigated by directly computing the gradient of the scattering parameters. It is shown that structures that are modular in the input-to-output direction are much less sensitive than those with modularity in the orthogonal direction for the same frequency response. View full abstract»

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  • Time-resolved measurements using conventional analog network analyzer

    Page(s): 1781 - 1786
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB) |  | HTML iconHTML  

    A new method of making precise time-resolved measurements using an unmodified analog network analyzer is described. This technique is most useful in wafer probing unpackaged acoustic devices in production conditions or in characterizing development acoustic devices that are packaged to allow easy physical access to the device and which may, therefore, exhibit high levels of RF feedthrough. 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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