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Microwave Theory and Techniques, IEEE Transactions on

Issue 10  Part 1 • Date Oct. 1996

 This issue contains several parts.Go to:  Part 2 

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Displaying Results 1 - 20 of 20
  • Interpolation/extrapolation of frequency domain responses using the Hilbert transform

    Publication Year: 1996 , Page(s): 1621 - 1627
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (682 KB)  

    The Hilbert transform relates the real and the imaginary parts of the transfer function of a causal system. The objective of this paper is to illustrate how the Hilbert transform relationship can be utilized to interpolate/extrapolate measured frequency domain responses of devices. Sample numerical examples are presented to illustrate the efficacy of this method. View full abstract»

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  • Multimode equivalent network representation for H- and E-plane uniform bends in rectangular waveguide

    Publication Year: 1996 , Page(s): 1679 - 1687
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    Uniform bends in rectangular waveguides are frequently used components in many microwave subsystems both for ground and space applications. Their accurate and efficient full-wave characterization is therefore required for the development of modern CAD tools to analyze and design complex waveguide structures. In this paper we describe new multimode network representations for both H- and E-plane uniform bends in terms of impedance and admittance multimode coupling matrices, respectively. The key element of the network is the transition from the straight waveguide to the curved waveguide. The relevant multimode equivalent network representation is obtained following a simple procedure that has already been used with success for other types of junctions involving straight waveguides. The convergency properties of the method are discussed, and comparisons between our simulations and theoretical and experimental data are presented, indicating that the approach proposed is at the same time accurate and computationally very efficient View full abstract»

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  • Modes and their stability of a symmetric two-element coupled negative conductance oscillator driven spatial power combining array

    Publication Year: 1996 , Page(s): 1628 - 1636
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB)  

    The modes and their stability of a symmetric two-element coupled negative conductance oscillator driven spatial power combining array were addressed theoretically. It was shown that the symmetric two-element spatial power combining array can produce two stable operation modes, one in-phase, the other 180°-out-of-phase. The theory explains all previously published experimental phenomena. Experiments done at C-band with a symmetric two element coupled Gunn oscillator driven spatial power combining array demonstrated the validity of the theory to a certain extent. The theory can be generalized to study the modes and their stability of any coupled oscillator driven spatial power combining arrays View full abstract»

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  • Loss-compensated distributed baseband amplifier IC's for optical transmission systems

    Publication Year: 1996 , Page(s): 1688 - 1693
    Cited by:  Papers (39)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (700 KB)  

    We describe a distributed baseband amplifier using a new loss compensation technique for the drain artificial line. The new loss compensation circuit improves a high-frequency performance of the amplifier and makes the gain bandwidth product of the amplifier larger than that of conventional ones. We also use dc matching terminations and dumping resistors for the gate and drain artificial lines to obtain flat gain from frequencies as low as 0 Hz. One IC fabricated using 0.1 μm-gatelength InAlAs/InGaAs/InP HEMTs has a gain of 16 dB over a 0-to-50 GHz band, resulting in a gain bandwidth product of about 300 GHz. Another IC has a gain of 10 dB over a 0-to-90 GHz band. These are the highest gain bandwidth product and the widest band reported for baseband amplifier ICs applicable to optical transmission systems View full abstract»

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  • The analysis of general two-dimensional PEC structures using a modified CPFDTD algorithm

    Publication Year: 1996 , Page(s): 1728 - 1733
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    The use of the contour path finite difference time domain (CPFDTD) method with locally distorted contours has been shown to give accurate results for curved metal structures. However, the numerical stability of this scheme is not guaranteed and significant skill is required in order to generate an appropriate grid. In this contribution, we present a modification to the CPFDTD scheme which ensures stability and give a step-by-step procedure for simple generation of the distorted grid. Examples are presented to demonstrate that the modified scheme yields results superior to those obtained using the standard staircased finite difference time domain (FDTD) approach. Example geometries are cylindrical cavities having complex cross-sections with smooth surfaces and right-angle bends. The accuracy of the method is demonstrated by comparison to analytical results where available View full abstract»

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  • Existence of a leaky dominant mode on microstrip line with an isotropic substrate: theory and measurements

    Publication Year: 1996 , Page(s): 1710 - 1715
    Cited by:  Papers (36)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    A newly discovered leaky dominant mode is reported for conventional microstrip line on an isotropic substrate, at higher frequencies. The existence of this leaky mode has been confirmed both numerically and experimentally. This new mode exists independently of, and in addition to, the customary bound dominant mode. It leaks power away from the line into the fundamental TM0 surface wave of the surrounding grounded substrate, and may therefore be responsible for spurious microstrip circuit performance at higher frequencies. This could have important implications for millimeter-wave circuits View full abstract»

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  • Chromatic dispersion in fiber-optic microwave and millimeter-wave links

    Publication Year: 1996 , Page(s): 1716 - 1724
    Cited by:  Papers (191)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB)  

    The influence of chromatic fiber-dispersion on the transmission distance of fiber-optic microwave and millimeter-wave links is analyzed and discussed in this paper. It is shown that dispersion significantly limits the transmission distance in intensity modulated direct detection links operating in the above 20 GHz frequency region by inducing a carrier to noise penalty on the transmitted signal. At 60 GHz, a 1 dB penalty is induced after less than 500 m transmission over standard single-mode fiber with a dispersion of 17 ps/km·nm and the signal is completely extinct after 1 km. In remote heterodyne detection links, the dispersion induces both a carrier to noise penalty and a phase noise increase on the transmitted signal. It is shown, however, that the induced carrier to noise penalty is insignificant. At 60 GHz, the induced penalty is less than 0.3 dB after 100 km transmission. The phase noise increase proves more dominant. At 60 GHz, a 150 Mbit/s QPSK signal is limited to around 10 km of transmission View full abstract»

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  • Analytical method for determining equivalent circuit parameters of GaAs FETs

    Publication Year: 1996 , Page(s): 1637 - 1641
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB)  

    An analytical method has been developed that gives a simple and practical means of extracting small-signal equivalent circuit parameters (ECPs) of GaAs FETs with negligibly small bond-pad capacitances. Only the S-parameter measurement of the pinched-off cold field-effect transistor (FET) is enough to determine the extrinsic FET ECPs. The intrinsic FET ECPs of a medium-power Ku-band GaAs FET chip with a total gate width of 800 μm have been analytically extracted for two types of eight-element intrinsic FET models; Model 1 (Curtice model) and Model 2 that differ in the control voltage (VG) definition. Model 2 with VG defined across the gate-source capacitance is found more appropriate judging from the smaller frequency dependence of the ECPs and a better agreement between the calculated and measured S-parameters over 2-20 GHz View full abstract»

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  • Extensions of the Chalmers nonlinear HEMT and MESFET model

    Publication Year: 1996 , Page(s): 1664 - 1674
    Cited by:  Papers (124)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (976 KB)  

    The ability to simulate temperature, dispersion, and soft-breakdown effects as well as a new α dependence was added to the Chalmers nonlinear model for high electron mobility transistor (HEMT's) and metal semiconductor field-effect transistor (MESFET's). DC, pulsed dc, low frequency (10 Hz-10 MHz), RF, and small signal S-parameter measurements (1-18 GHz) have been made on a large number of commercial HEMT and MESFET devices from different manufacturers in the temperature range 17-400 K in order to evaluate the validity of the model extensions View full abstract»

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  • Microwave noise characterization of two-port devices using an uncalibrated tuner

    Publication Year: 1996 , Page(s): 1725 - 1728
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    A novel noise-parameter and S-parameter measurement system is proposed. Any device under test (DUT) can be characterized using the proposed setup. Such characterization is performed without any preset conditions on the input impedance of the noise-receiver and the repeatability of the impedance tuning mechanism. The DUT is used as a standard for tuner calibration. Measurements were carried out on a general purpose GaAs-MESFET. The extracted transistor noise-parameters are in good agreement with the manufacturer's specified values over the operating frequency band (4-8 GHz) View full abstract»

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  • CAD model for coplanar waveguide synthesis

    Publication Year: 1996 , Page(s): 1733 - 1738
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    Accurate closed-form synthesis formulas for coplanar waveguides are presented for CAD applications, which are approximated in terms of ordinary functions. These formulas are derived from function approximation and curve-fitting correction of quasi-static numerical results. Comprehensive comparisons have been made by using results from the quasi-static analysis, the rigorous full-wave analysis, and the experiment available in the literature. Accuracy is found to be better than 1.5 percent for the practical range. The application range of frequency is within the limits well known for quasi-static TEM approximation and can be applied up to 20 GHz View full abstract»

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  • Ridge coplanar waveguide for optical amplitude modulation

    Publication Year: 1996 , Page(s): 1675 - 1678
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    A novel structure called ridge coplanar waveguide is proposed for Mach-Zhender optical modulator. Numerical modeling using a two-dimensional finite-difference time-domain (2D-FDTD) algorithm has shown that a ridge coplanar waveguide on Y-cut LiNbO3 substrate without SiO2 buffer layer yields very high efficiency of modulation over a wide frequency bandwidth View full abstract»

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  • Photovoltaic-FET for optoelectronic RF/μwave switching

    Publication Year: 1996 , Page(s): 1747 - 1750
    Cited by:  Papers (9)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (332 KB)  

    A photovoltaic-FET (PV-FET) is demonstrated for RF/μwave switching with performance improved over other optoelectronic switches reported while operating with 10-100 times less optical power. The PV-FET characteristics were 3 Ω on-resistance, >30 MΩ off-resistance under <1 mW optical power, and 300 fF switch capacitance. This PV-FET was inductor tuned at 790 MHz and 7.4 GHz to enhance isolation, intended for reconfigurable antenna applications. The measured insertion loss and isolation agree well with those from theoretical calculation and numerical circuit simulation based on the switch parameters. The measured switch rise and fall times were 20 μs and 2 μs, respectively. Controlled by light via optical fiber, the PV-FET can be used for remote RF/μwave switching control with no electrical bias, complete electromagnetic, and good thermal isolation View full abstract»

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  • Low cost and compact active integrated antenna transceiver for system applications

    Publication Year: 1996 , Page(s): 1642 - 1649
    Cited by:  Papers (24)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (700 KB)  

    Integrated and active antennas incorporate component functions directly at the antenna terminals thereby reducing the size, weight, and cost of many microwave systems. Active integrated antennas have been used for distributed oscillators in spatial and quasi-optical power combining arrays, but the concept can be extended to include such applications as Doppler sensors, radars, and wireless communications to produce compact, low-cost products. In this paper, we report that a field-effect transistor (FET) and a Schottky mixer diode have been integrated within an inverted patch antenna for transceiver applications. The position of the mixer diode on the patch was optimized to achieve a minimum conversion loss. Preliminary results exhibit a 5.5 dB isotropic mixer conversion loss at 6 GHz for a 200 MHz intermediate frequency. The FET serves as both the transmitter and the local oscillator at 5.8 GHz. A two-way communication system using these transceivers is proposed View full abstract»

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  • Capacitance of microstrip lines with inhomogeneous substrate

    Publication Year: 1996 , Page(s): 1703 - 1709
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    A mode-matching approach combined with Galerkin's method is proposed in this paper to calculate the capacitance matrix of microstrip lines embedded in an inhomogeneous stratified medium. Eigenmodes in each layer are first solved numerically, and the potential in each layer can be expressed in terms of these eigenmodes. Coupling between two sets of eigenmodes in contiguous layers is described by defining reflection matrices. A Green's function is thus obtained in terms of these eigenmode sets to relate the potential to a line charge. Integral equation is then constructed relating the charge distribution and the imposed voltage on the microstrip surface. Galerkin's method is next applied to solve the charge distribution and hence the capacitance matrix. Several inhomogeneous profiles are studied to understand the effects of inhomogeneities on the capacitance and relevant parameters View full abstract»

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  • Finite element analysis of MMIC waveguide structures with anisotropic substrates

    Publication Year: 1996 , Page(s): 1650 - 1663
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1292 KB)  

    This paper presents an extended finite element formulation for a full-wave analysis of biaxial and transverse plane electric and magnetic anisotropic materials with application to monolithic microwave integrated circuits (MMIC's). A convenient formulation of the characteristic impedance based on a power-voltage definition is developed using vector-based finite elements. The resultant generalized eigenvalue problem is solved using a numerically efficient algorithm based on a forward iteration, taking full advantage of the sparsity of the involved matrices. Numerical results are compared and agree well with existing published data for various MMIC configurations. Two specific coplanar waveguide structures, one with a conventional and the other with a suspended substrate, are examined using four common anisotropic materials. Principal axis rotations of the anisotropic substrates are also considered to improve dominant mode dispersion characteristics and minimize higher order mode interactions View full abstract»

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  • A simple technique for the design of MMIC 90° phase-difference networks

    Publication Year: 1996 , Page(s): 1694 - 1702
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (708 KB)  

    In this paper, a simple technique for the design of broadband 90° phase-difference networks, using balanced and unbalanced all-pass network topologies, is presented. In the developed method, the element values of the structures are calculated as function of two design variables: Q0 and r. Utilizing this approach, a 90° phase shifter has been realized, having less than 2° phase error and better than 0.5 dB amplitude error in the operating band from 0.7 to 3.5 GHz View full abstract»

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  • Electrostatic potential distribution through a rectangular aperture in a thick conducting plane

    Publication Year: 1996 , Page(s): 1745 - 1747
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    A potential distribution through a rectangular aperture in a thick conducting plane is examined when the incident electric field is normal to the rectangular aperture. The Fourier-transform is used to represent the potential in the spectral domain and the boundary conditions are enforced to represent a solution in closed form. Numerical computations are performed to illustrate the behavior of the potential distribution through a thick rectangular aperture. Our solution for the electric polarizability is represented in rapidly converging series so that it is numerically efficient View full abstract»

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  • Transient analysis of tapered lines based on the method of series expansion

    Publication Year: 1996 , Page(s): 1742 - 1744
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (220 KB)  

    Step response of tapered lines under matched conditions is studied in detail by a novel method of series expansion. We use the concept of fall time to characterize the transient characteristics and, by using approximate formulas concerned with Gaussian pulse, response characteristics are derived which may be a guide in practical applications of tapered line. The effectiveness of the formulas is verified by numerical calculations View full abstract»

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  • Lower order modes of YBCO/STO/YBCO circular disk resonators

    Publication Year: 1996 , Page(s): 1738 - 1741
    Cited by:  Papers (20)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    Lower order modes in a single crystal strontium titanate (STO) circular disk resonator are studied experimentally. Superconducting epitaxial YBCO films form the parallel-plates of the resonator. Due to the extremely high dielectric constant of STO, the electric fields are concentrated between the plates, while there is a substantial magnetic fringing field which affects both the resonant frequencies, Q-factors, and tunability of all modes, especially the TM110 and TM210 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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