Microwaves, Antennas and Propagation, IEE Proceedings H (IEE Proc H Microwaves Optic Antenn )

Publisher: Institution of Electrical Engineers

Description

Discontinued in 1984. Continued by IEE Proceedings - Part H: Microwaves, Antennas and Propagation (0950-107X). Classification: Microwave antennas; Microwaves.

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  • Website
    IEE Proceedings - Part H: Microwaves, Optics and Antennas website
  • Other titles
    IEE proceedings. Part H, Microwaves, antennas, and propagation, Institution of Electrical Engineers proceedings. Part H, Microwaves, antennas, and propagation, Microwaves, antennas, and propagation, IEE proceedings
  • ISSN
    0143-7097
  • OCLC
    12070418
  • Material type
    Periodical, Internet resource
  • Document type
    Journal / Magazine / Newspaper, Internet Resource

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: The dispersion relationships for microstrip-slot lines are analysed by the spectral domain method and evaluated numerically as a function of plasma density for an optically induced plasma. The frequency range considered corresponds to the W and D band range, and the microstrip is realised on high-resistivity silicon. The experimental work was undertaken at frequencies ranging from 90 to 170 GHz using 5 kΩ cm silicon substrates with different strip widths irradiated by light emitting diodes radiating at a wavelength of 820 nm. Optical control was confirmed by measuring the change in propagation loss resulting from the illumination. A wave attenuation of 10 dB was determined for a line length of 30 mm, and a plasma relaxation time of 120 μs was measured at 137 GHz. Applications of this line are briefly discussed
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: Radiation characteristics of an insulated dipole antenna immersed in an arbitrary medium are studied using a complete formulation of the problem. Electric and magnetic equivalent surface currents are used to formulate a system of integro-differential equations. These equations are solved using the method of moments construction with of basis functions. The data obtained are found to be in good agreement with the available data in the literature. The effect of the insulator's permittivity on the near field and far field of the dipole is discussed. The use of coating materials to control the effective length of the dipole is presented. The effect of the insulator's thickness on the far field is also studied. The input impedance or the insulated antenna in arbitrary medium is obtained
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: The surface-wave admittance of a circular patch antenna with finite ground plane dimensions is formulated. The orthogonal relationship between the space wave and various surface-wave modes is invoked to determine the amplitude of a surface-wave mode produced by the equivalent magnetic current of the patch. The surface wave admittance, and hence the input impedance of a patch is found to vary widely with the ground plane size. Numerical results for the input impedance agree well with the measured data which confirms the validity of the formulation
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: An analytic solution to the problem of the scattering of a plane electromagnetic wave by an arbitrary configuration of dielectric spheres is presented using an iterative procedure to account for the multiple scattered fields between the spheres. To compute the higher order terms of the scattered fields, the translation addition theorem for the vector spherical wave functions is used to express the field scattered by one sphere in terms of the spherical co-ordinates of the other spheres to impose the boundary conditions. Coefficients of the various order scattered fields are obtained in matrix form. Numerical results for the normalised backscattering and bistatic cross-section patterns are presented for one- and two-dimensional arrays, and these show that scattered fields up to the fourth order are needed in the special case of contacting conducting linear arrays of spheres to achieve results in excellent agreement with the available data published in the literature
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: A comprehensive analysis of spherical circular microstrip patch antennas is presented. The dielectric thickness is considered to be thin. Computation of the wall admittance is also presented. The input impedance is computed using the generalised transmission line model. The values of the input impedance and the resonance frequency are found to be comparable with that of a planar structure when the sphere radius is large. The radiation patterns are computed numerically using the method of moments. The effect of different parameters on the antenna characteristics is investigated
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: The parallel-plate guide opens, through a slot aperture in an infinite screen, into a semi-infinite half-space in which resides a perfectly conducting cylinder of arbitrary cross-section whose axis is parallel to that of the slot. The excitations considered for this structure are: (a) a TEM wave in the guide and (b) a line source in the region exterior to the guide. Coupled integral equations for the aperture electric field (or equivalent magnetic current) and the cylinder current are derived from first principles and are solved numerically for cylinders of various cross-section, size and location relative to that of the slot aperture. From knowledge of aperture electric field and cylinder current, all other quantities of interest may be determined: voltage received in the guide, guide reflection coefficient and far-zone radiation. Data are presented that illustrate how the cylinder loads the guide, modifies its radiation pattern and serves as a shield for a the aperture. From the data, one can assess the effectiveness of a conducting shield placed over, but not in contact with, the guide aperture
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: The theory and design of a reconfigurable mesh reflector antenna is described with particular reference to satellite applications. As an example, it is shown that antenna pattern reconfiguration can be achieved for a 50-wavelength-diameter antenna using 78 actuators with performance very comparable with that prescribed for an antenna fed from an array. The predicted performance relies on an accurate mechanical model for the knitted mesh surface, which is developed here using a network of elastic springs. The effectiveness of the model is demonstrated. Other factor affecting performance, such as boundary constraints and the means to control the mesh surface, are discussed together with tolerances on actuator settings
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: The characteristics of multiple concentric open and closed ring microstrip structures are computed in terms of the distributed self and mutual capacitances and inductances. The spectral domain technique is used to compute these quasi-stances and inductances of the multiple coupled concentric rings. The coupled ring structures are modelled as asymmetric and multiple coupled line circuits which are used to evaluate resonance frequencies and other multiport characteristics of these structures
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: Pulse sharpening using ferrite material was first noticed in the mid-fifties during the development of storage devices for telecommunication and computer systems. Since that time various workers have explained how a switched ferrite can change the propagation characteristics of a transmission line to improve the rise time of an input pulse. In the paper the advantages achievable by imposing electron spin resonance and subsequent frequency enhancement, which has greatly improved the performance of these lines, are described for the first time. Experimental evidence of the benefits of spin conditions is provided and a simple transmission line model introduced to simulate the pulse sharpening effects
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: A simple beamforming approach is used to estimate the direction of arrival of plane waves in white noise. The basic idea of the approach is to minimise the mean-square value of the difference between the actual array response and the desired unity response in certain directional regions while imposing directional eigenvector constraints obtained from the correlation matrix. This is illustrated with numerical results. The connection between this bearing estimation scheme and the minimum norm spatial spectral estimator is also discussed
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: The paper explores reflection and transmission characteristics of single and multilayer chiral slabs. The analysis is based on vector circuit modelling of chiral slabs in terms of transverse fields, dyadic impedance, admittance or transmission matrix components. Reflection and transmission coefficients for arbitrary angles of incidence and arbitrary polarisation states of the fields are derived. From these coefficients and to exemplify the method, reflected and transmitted fields of the co- and cross-polarised waves are calculated in single and multilayer chiral slabs for various electromagnetic and geometrical parameter values
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: The transmission line method provides a computationally efficient technique for obtaining the input impedance of a folded dipole. The method is limited however to cases where the separation between the parallel wires of the folded dipole is less than 1/100th of a wavelength. The paper extends the use of the method to include folded dipoles with spacings less than 1/6th of a wavelength. This is achieved by using an extended equivalent length based on the inter-element spacing of the folded dipole. The physical length of the folded dipole is increased by an extension factor of 0.39 times the inter-element spacing. The factor is obtained by numerical experiments using the NEC2 method of moments program and this is also used to generate the comparative results
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: The attenuation function, normalised with respect to the free space field, for waves propagating over a perfectly conducting, nonlevel plateau situated on a perfectly conducting ground plane, is derived. The general case of having a raised transmitter and receiver is considered. A high frequency path integral formulation is employed to obtain an approximate propagator for a sloping ground plane geometry. The plateau propagator is derived by using the above result as an elementary building block and is given by a sum of general surface Fresnel integrals. The paper also includes the solution to the problems of propagation over two perfectly absorbing half planes, and propagation over a sloping roof plateau situated on a perfectly absorbing ground plane as special cases. Numerical results show that the result contains the solution obtained by the compensation theorem for a flat-roof plateau, when both the source and the observation points are set at ground level. The validity of the solution is also confirmed by laboratory experiments
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: In many integral equation formulations, impedance matrix elements derived for a moment method solution may not be computable. This happens when the summations involved tend to diverge because of a poor choice of basis and testing functions. In cases amenable to the spectral representation, these phenomena can be predicted and avoided, as shown in the paper. The development for many planar structures is shown in a general manner and guidelines. for the selection of basis and testing functions for the generation of convergent matrix elements are deduced. The guidelines are applied to the Galerkin formulation, where the decay rate of the spectral basis functions has a double effect on the integrand. Finally, the analysis is applied to waveguide problems, where the full three-dimensional spectral Green's dyad is used. These principles are worked out for transversal slots in waveguides, where divergence has been observed in the past. A stable formulation is then derived and results are presented
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: For pt.1 see ibid., vol.138, no.6, p.485-92 (1991). The paper describes the performance of an electronically controlled reconfigurable mesh reflector antenna operating at a frequency of 10 GHz. The antenna, which is controlled from a personal computer, is capable of being reconfigured to achieve a wide range of antenna patterns. Patterns are measured using the QMW compact antenna range and excellent agreement is obtained between measured and predicted results. Reconfiguration between a high-gain beam and a shaped beam is demonstrated as well as the potential for beam scanning without feed movement
    Microwaves, Antennas and Propagation, IEE Proceedings H 01/1992;
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    ABSTRACT: An analysis of a conducting post with arbitrary cross-section and height in a rectangular waveguide is given. The problem is solved by the method of moments in two ways. The first way is to solve the electric field integral equation (EFIE) for a thin post, for the current distribution along the post. The second way is to solve the magnetic field integral equation (MFIE) for a thick post. The equivalent circuits are evaluated, and the computed results show good agreement with experimental ones given by Marcuvitz (1951)
    Microwaves, Antennas and Propagation, IEE Proceedings H 11/1991;
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    ABSTRACT: A moisture sensor is described that consists of a microwave circuit working at 2.45 GHz. The system is an interferometer, a part of which is formed on a Duroid substrate. The characteristics of the system are analysed and discussed. Preliminary experiments, made on different materials, for moisture contents smaller than 16%, show the accuracy of the sensor to be better than within ±0.1%
    Microwaves, Antennas and Propagation, IEE Proceedings H 11/1991;
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    ABSTRACT: The efficiency of travelling-wave tubes (TWTs) operated under nonlinear conditions is usually enhanced by adjusting the phase velocity of the slow-wave circuit towards the output end of the tube. This technique, known as tapering, aims to maintain the optimum phase relationship between the electron bunches and the slow electromagnetic wave. The paper describes the results of a study of taper design carried out using a one-dimensional large signal computer model of coupled-cavity TWTs. An improved taper design procedure for broad-band TWTs is suggested
    Microwaves, Antennas and Propagation, IEE Proceedings H 11/1991;
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    ABSTRACT: The paper presents a hybrid method for the computation of scattered fields from a leaky halfplane illuminated by an electric line source. The structure consists of a large array of nonuniformly spaced, thin, perfectly conducting coplanar strips near the edge of a perfectly conducting halfplane. The analysis is carried out by a combination of the integral equation and physical optics methods. The solution for the current distribution on the strips is obtained by the use of the conjugate contrast source truncation iterative algorithm. Thus, matrix inversion is circumvented and the method is particularly well suited for large arrays of strips. An approximate procedure based on a physical optics derived resistive taper is given for the synthesis of strip spacings. Numerical results indicate that a moderate increase in diffraction loss in the halfplane shadow region is feasible by a judicious choice of strip spacing. Advantages and limitations of the method are also discussed
    Microwaves, Antennas and Propagation, IEE Proceedings H 11/1991;
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    ABSTRACT: The backscatter pattern of a long, perfectly conducting cylinder with flat endcaps exhibits a travelling wave lobe near end-on in the case of a θ-polarised incident electric field. The paper uses a method that combines the MOM and the UTD to isolate the travelling wave contribution, and approximate expressions are obtained empirically to correct the backscatter pattern calculated by means of the UTD, which does not include the travelling wave contribution. The travelling wave contribution is subsequently studied as a function of cylinder diameter and length
    Microwaves, Antennas and Propagation, IEE Proceedings H 11/1991;

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