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Microwaves, Antennas and Propagation, IEE Proceedings H

Issue 3 • Date Jun 1992

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Displaying Results 1 - 16 of 16
  • Uniform GTD solution for the diffraction by metallic tapes on panelled compact-range reflectors

    Publication Year: 1992 , Page(s): 297 - 305
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    Metallic tape is commonly used to cover the interpanel gaps which occur in panelled compact-range reflectors. It is therefore of interest to study the effect of the scattering by the tape on the field in the target zone of the range. An analytical solution is presented for the target zone fields scattered by 2D metallic tapes. It is formulated by the generalised scattering matrix technique in conjunction with the Wiener-Hopf procedure. An extension to treat 3D tapes can be accomplished using the 2D solution via the equivalent current concept. The analytical solution is compared with a reference moment method solution to confirm the accuracy of the former View full abstract»

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  • Design of millimetre wave dielectric resonators for integrated circuits

    Publication Year: 1992 , Page(s): 307 - 308
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    Whispering gallery modes in high permittivity right cylindrical dielectric resonators are shown to be very useful at millimetre wavelengths since they offer a high Q factor and their oversized dimensions make them easy to manufacture. Using a dielectric waveguide model, simple expressions are generated that accurately predict the resonant frequencies of the WGE whispering gallery modes within right cylindrical dielectric resonators placed on a dielectric integrated circuit substrate of lower permittivity. Theoretical and experimental results are given and the accuracy of the proposed model is shown to be good View full abstract»

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  • Equivalent circuit of a cavity coupled to a feeding line and its dependence on the electric or magnetic nature of output coupling structure

    Publication Year: 1992 , Page(s): 221 - 226
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    It is demonstrated that the type of equivalent network of a resonator depends only on the coupling configuration. Based on experimental results, electric or magnetic coupling is considered, and two particular cases are described. In the case of a thick iris, a rigorous equivalent network is proposed; and in the case of a probe-coupled cavity, a new theoretical approach is presented View full abstract»

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  • Scattering by an electrically small bianisotropic sphere in a gyroelectromagnetic uniaxial medium

    Publication Year: 1992 , Page(s): 217 - 220
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    Scattering by an electrically small bianisotropic sphere embedded in a hydroelectromagnetic uniaxial medium is considered. A simple scattering formalism is presented which can be applied to a wide class of media, artificial and natural, which are covered by the general constitutive relations used. The equivalent polarisability dyadics have been obtained in the long wavelength approximation. The results are pertinent to some dilute discrete random composites View full abstract»

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  • Power combining efficiency and its optimisation

    Publication Year: 1992 , Page(s): 233 - 238
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (508 KB)  

    The power combining efficiency of an n-way power combiner is calculated in terms of the scattering matrix of the combiner network, and the factors affecting it are identified. The maximum value of the combining efficiency is then deduced, for a given power combiner with known network parameters, under various sets of constraints on the amplitudes and phases of the signals being combined. In each case, the signal conditions needed to achieve the maximum efficiency are determined View full abstract»

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  • Full wave analysis for the equivalent circuit of an inclined slot in a microstrip ground plane

    Publication Year: 1992 , Page(s): 245 - 250
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    The problem of a radiating slot on the ground plane of a microstripline is solved using the spectral domain approach. The equivalent circuit for the configuration is obtained, and the elements are determined using the integral transformation techniques. Effects of various parameters, such as slot dimensions and inclination with the feedline, are studied. Results are compared with measurements, and reasonable agreement is obtained. The results and the approach should find useful applications in integrated circuits and aperture-coupled patch antennas View full abstract»

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  • Analysis of triangular patch antennas including radome effects

    Publication Year: 1992 , Page(s): 251 - 256
    Cited by:  Papers (4)  |  Patents (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    The full-wave spectral domain technique is used for the first time to analyse the single and covered triangular patch antennas fed by the coaxial probe. The equilateral triangular patch antenna fed by a probe along the patch median was analysed and its input impedance and radiation patterns are presented. The effects of flat radomes on these parameters are studied. To avoid excessive computation time, three sets of basis functions representing the approximate current distributions on the patch are introduced. Merits of each set of basis functions are discussed. Various tests were made to establish the validity of the basis functions, including comparisons of the results against those obtained by the cavity model and against those of some experimental observations View full abstract»

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  • Analysis of broadside coupled microstrip open-end discontinuities

    Publication Year: 1992 , Page(s): 239 - 244
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    The capacitive equivalent circuit and the modal equivalent lengths of the symmetric broadside coupled microstrip open-end discontinuity are calculated in the case in which the conducting strips are embedded in a multilayered dielectric medium. The Galerkin method in the spectral domain is applied to solve the excess charge densities existing on the conducting strips of the discontinuity both in even and odd modes of excitation. Results are presented for broadside coupled microstrip open ends in conventional, suspended and inverted configurations View full abstract»

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  • Modified indirect boundary element technique and its application to electromagnetic potential problems

    Publication Year: 1992 , Page(s): 292 - 296
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    A modified indirect boundary element formulation is developed following a weighted residual approach. In this formulation, the fictitious source density, which appears in the integral equations of the method, is distributed on a surface which is exteriorly separated from the physical field boundary of the problem. The method does not require the evaluation of singular integrals and produces undeteriorated solutions at geometric discontinuities. The technique is applied to two-dimensional electromagnetic potential problems, and several examples are investigated View full abstract»

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  • Silicon monolithic millimetre-wave integrated circuits

    Publication Year: 1992 , Page(s): 209 - 216
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (708 KB)  

    Using silicon as the substrate material, silicon monolithic millimetre-wave integrated circuit (SIMMWIC) oscillators and receivers are successfully realised. For the coplanar oscillators, a slot is used as the resonant structure in which a monolithically integrated IMPATT diode, selectively grown by silicon molecular beam epitaxy (Si-MBE), acts as the negative resistance device. Pulsed and CW operation of the planar oscillators is achieved in the 90 GHz region. The output power is radiated directly from the resonant slot. Complete receivers, with monolithic Schottky diodes together with the antenna, are integrated on a single chip. The suitability of the chips for near-range measurements is pointed out View full abstract»

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  • Frequency domain behaviour of coupled-line digital frequency multipliers

    Publication Year: 1992 , Page(s): 271 - 277
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (332 KB)  

    Coupled-line digital frequency multipliers are described from the frequency domain behaviour, where certain discrete frequency components of input pulses are eliminated and others are passed with minimum attenuation. The simulated waveforms from measured data are found to be in good agreement with experiments. The proposed multipliers can function under TEM wave propagation. The effect on unequal phase velocities is also considered View full abstract»

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  • Radiation pattern computation of microstrip antennas on finite size ground planes

    Publication Year: 1992 , Page(s): 278 - 286
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    A method for the computation of radiation patterns of microstrip antennas on substrates of finite dimensions by a combination of the mixed potential integral equation technique (MPIE) for patch antennas and the weak form of the conjugate gradient-fast fourier transform (WCG-FFT) method for the scattering by the finite ground plane is presented. The computation is carried out in three steps. The MPIE formulation is first used for the accurate evaluation of the current distribution on the conducting surface of the patch. Using these currents as primary sources, equivalent polarisation currents in the dielectric slab are then evaluated. These two steps are based on the infinite grounded dielectric slab assumption. Finally the current distribution on the finite ground plane is determined using the WCG-FFT method. Since matrix inversion is not involved in the last step, the method is very convenient for treating small to moderate size ground planes. An alternative approach for the derivation of far field patterns of microstrip antennas on an infinite grounded dielectric slab using the volume equivalence theorem and image theory is also presented. Numerical results of radiation patterns have been verified experimentally View full abstract»

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  • Characteristic modes of a slot in a conducting cylinder and their use for penetration and scattering, TM case

    Publication Year: 1992 , Page(s): 287 - 291
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    Characteristic mode theory is presented as a method of calculating the characteristic currents, the equivalent magnetic current, the radiation patterns, and the field everywhere (especially in the aperture region) of an infinitely long, thin, perfectly conducting cylinder with an infinitely long slot illuminated by a uniform transverse magnetic (TM) plane wave to the slot. The characteristic modes obtained are the solution of an eigenvalue equation representing the continuity of the tangential component of the magnetic field in the slot View full abstract»

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  • Supercooled and superconducting small-loop and dipole antennas

    Publication Year: 1992 , Page(s): 264 - 270
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    To assess the performance of electrically small antennas, the two most fundamental antennas, namely electric and magnetic dipoles, have been chosen for examination of their performance in a superconducting environment. Aspects of the two antennas and their matching networks that are discussed include efficiency, Q, input impedance, power gain, power handling and signal/noise ratio. Both transmitting and receiving performances are considered. Finally, experimental results for loop and dipole antennas constructed out of YBCO wire are presented and compared with their supercooled copper counterparts. In this, they show a significant improvement in efficiency View full abstract»

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  • Nonreciprocal devices using ferrite ring resonators

    Publication Year: 1992 , Page(s): 257 - 263
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (484 KB)  

    Novel nonreciprocal components based on hollow ferrite discs, i.e. ferrite ring resonators, are discussed. Some three-port and four-port components are analyzed, and some design guidelines are presented. It is shown that a ring structure requires a smaller diameter and ferrite thickness than a disc structure for the same frequency. A ring also provides another variable in design and permits ports to be connected to the inside as well as the outside. Novel components and increased component density may therefore be possible at the expense of bandwidth View full abstract»

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  • New ferrite-filled waveguiding structures analysed by the averaging method

    Publication Year: 1992 , Page(s): 227 - 232
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (444 KB)  

    Waves in some sophisticated waveguiding structures, filled with magnetised ferrite, are investigated. Anisotropic boundary conditions are supposed to be valid on some of the walls of the waveguides, whence the results allow, for instance, an analysis of ferrite-filled corrugated waveguides and microstrip lines with corrugated strips. For solving the related electromagnetic problems, a new approximate technique-averaging method-is used. The main idea is to average the field inside a waveguide, assuming that the components tangential to the interfaces are locally quasistatic. The present technique can be used when one of the transversal dimensions of a waveguide is much smaller than the wavelength in that direction. The results could help to develop different devices, such as controlled phase-shifters and isolators View full abstract»

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