Home
>
Journals & magazines
>
IEE Proceedings H (Microwaves, Antennas and Propa...
>
Volume 136
Issue 3
IEE Proceedings H (Microwaves, Antennas and Propagation)
Volume 136, Issue 3, June 1989
Volumes & issues:
Volume 136, Issue 3
June 1989
Scattering by a perfectly conducting strip loaded with a dielectric cylinder (TM case)
 Author(s): A.Z. Elsherbeni and M. Hamid
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 185 –190
 DOI: 10.1049/iph2.1989.0035
 Type: Article
 + Show details  Hide details

p.
185
–190
(6)
A rigorous analysis of the problem of scattering from an incident Epolarised wave on a dielectricloaded perfectly conducting strip is presented for a line source and plane wave excitations. The vector Green's theorem is used to derive an integral equation for the unknown electric and magnetic field components. The singular component of the magnetic field is then cancelled out by properly choosing the auxiliary fields and boundary conditions. The unknown expansion coefficients of the scattered electric field are determined by numerically solving an infinite set of simultaneous linear equations after truncation. The accuracy of the proposed solution is verified for the loaded and unloaded strip by comparing the resulting values of the scattered field with those based on the method of moments. For the loaded strip, the dependence of the scattered field as well as the scattering crosssections on the strip width, dielectric constant and angle of incident wave is investigated and presented for plane wave incidence.
Analysis of asymmetric TEM cell and its optimum design of electric field distribution
 Author(s): X.D. Cai and J.Y. Li
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 191 –194
 DOI: 10.1049/iph2.1989.0036
 Type: Article
 + Show details  Hide details

p.
191
–194
(4)
By using the Green's function/variational formulation with a new form of charge distribution, expressions for the characteristic impedance and electric (E) field are obtained for an asymmetric TEM cell. The main details of a series of computer programs to implement an optimum design of the Efield distribution are presented in this paper.
Propagation and radiation from partly filled elliptical waveguide
 Author(s): G.L. James
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 195 –201
 DOI: 10.1049/iph2.1989.0037
 Type: Article
 + Show details  Hide details

p.
195
–201
(7)
The propagation and radiation behaviour from a partly filled (with dielectric) elliptical waveguide is considered. From an approximate analysis we investigate the potential of such a waveguide for radiating a pure circularly polarised shaped beam. We also establish a quantitative measure of the deterioration in linear cross polarisation performance of a balanced hybrid mode with loss of circularity.
Nearfield measurements on planepolar facility
 Author(s): J.C. Bennett and K.S. Farhat
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 202 –208
 DOI: 10.1049/iph2.1989.0038
 Type: Article
 + Show details  Hide details

p.
202
–208
(7)
Among the geometries used for acquiring the nearfields of microwave antennas, the planepolar geometry is the most recent. This contribution describes farfield predictions obtained on a recently built planepolar facility. The procedure for the transformation of the nearfield to the farfield uses a fast algorithm for the calculation of the radiation integral and is presented in the form of a cross correlation which is carried out using the fast Fourier transform. Predictions of the farfield patterns of two antennas are shown. A numerical algorithm for the interpolation of the nearfield from the planepolar grid to the cartesian grid is derived and the interpolated data is used to predict the farfield patterns of the two antennas. A direct result of the interpolation to a cartesian grid is the adaptability of the nearfield to processing for antenna metrology, enabling the surface diagnosis of antennas under test from measured planepolar data. A technique for phase drift compensation is presented and verified. The phase drift compensation procedure is particularly suited for the planepolar geometry.
EM wave scattering from statistically inhomogeneous and periodic random rough surfaces
 Author(s): D.P. Chrissoulidis
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 209 –214
 DOI: 10.1049/iph2.1989.0039
 Type: Article
 + Show details  Hide details

p.
209
–214
(6)
Firstorder scatter from statistically inhomogeneous and periodic random rough surfaces is treated by the boundary perturbation technique. The single array of rough strips on a perfectly conducting plane and the complementary arrays of rough strips are examined. Using a sampling approach, it is proved that scatter is produced through a multiple Bragg resonance mechanism. The scattering behaviour of the single array of rough strips is investigated numerically. Scatter for the corresponding surface which is covered throughout by roughness is used as reference. The numerical results indicate that the incidence/scattering directions are related to the orientation of the strips while the sensing radio wavelength is related to the strips width and period. Possible applications for this class of scatterers are discussed.
Technical memorandum: Design of Eplane filters made easy
 Author(s): JiaSheng Hong
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 215 –218
 DOI: 10.1049/iph2.1989.0040
 Type: Article
 + Show details  Hide details

p.
215
–218
(4)
Simple and effective models for the equivalent circuit parameters of waveguide Eplane metal septum are presented. It makes the design of Eplane bandpass filters very easy. The computerpredicted frequency responses were found to be in good agreement with the measurements.
Matching using double slug transformer and correction to transistor gain
 Author(s): J.R.G. Twisleton
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 219 –224
 DOI: 10.1049/iph2.1989.0041
 Type: Article
 + Show details  Hide details

p.
219
–224
(6)
Matching using a coaxial double slug transformer particularly in relation to measurements on microwave transistors at 0.5–2 GHz, is described. The limits arising from tuner loss and the correction to transistor gain which needs to be applied are determined analytically. The correction is compared with that deduced from reflection measurements, good agreement being obtained. The use of parallel plate line is investigated and from its Qfactor is shown to be a possible lower loss alternative to coaxial line in this application, provided that small radiation effects can be suppressed.
Electromagnetic diffraction by two perfectly conducting wedges with dented edges loaded with a dielectric cylinder
 Author(s): A.Z. Elsherbeni and H.A. Auda
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 225 –234
 DOI: 10.1049/iph2.1989.0042
 Type: Article
 + Show details  Hide details

p.
225
–234
(10)
A rigorous field analysis of the problem of two identical perfectly conducting parallel wedges with dented edges loaded with a dielectric cylinder, and excited by an electric or magnetic line current in the upper sector, is given in this paper. The dielectric medium is assumed to be linear, homogeneous, isotropic and free from losses, whereas the mediums of the upper and lower sectors are free space. A field equivalence theorem is used to derive, for each excitation, a system of coupled integral equations for the equivalent magnetic currents on the dielectric interfaces, which is later solved using Galerkin's method. The fields and powers transmitted into the lower sector, hence the transmission coefficients, for both polarisations are subsequently determined in terms of the equivalent magnetic currents on the lower dielectric interface. The analysis is then specialised to the problem of a slit loaded with a dielectric cylinder, as well as to the case of plane wave excitation. Sample numerical results for the dielectricloaded double dented wedge and slit problems in the case of plane wave excitation are also given.
Aperture impedance of flared horns
 Author(s): J.W. Silvestro and R.E. Collin
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 235 –240
 DOI: 10.1049/iph2.1989.0043
 Type: Article
 + Show details  Hide details

p.
235
–240
(6)
The method of moments is often used when solving for the mutual coupling in arrays of aperture antennas. For elements that are waveguides or gradually flared horns the aperture fields can be approximated by a finite sum of waveguide modal functions. To solve for the flared horn case an approximation for the aperture impedances of the modes in the horn is needed. The WKB approach can be used to find these impedances, but this technique has an important limitation. It is known to fail in the vicinity of it's turning points. The turning point is the cutoff point of the mode being considered. To overcome this limitation a different technique, the spherical mode approach, is discussed. This approach has no cutoff problems and works well for conical and pyramidal horns. Comparisons between the impedances and the resulting dominant mode reflection coefficient found using the two techniques are presented to illustrate this point.
Reflection coefficient at the feed of a radomecovered reflector antenna: a geometrical optics approach
 Author(s): H. Cory ; P.D. Einziger ; R. Sover
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 241 –244
 DOI: 10.1049/iph2.1989.0044
 Type: Article
 + Show details  Hide details

p.
241
–244
(4)
A previously derived asymptotic expression for the reflection coefficient at the feed of a paraboloidal reflector antenna covered with a paraboloidal radome is shown to be valid, with suitable modifications, for general reflectorradome configurations. This generalisation is illustrated through the particular choice of a paraboloidal reflector covered with a spherical radome. The generalised asymptotic expression for this geometry agrees very well with the numerically calculated integral expression obtained by the power coupling theorem.
Generalised Villeneuve n̅ distribution
 Author(s): D.A. McNamara
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 245 –249
 DOI: 10.1049/iph2.1989.0045
 Type: Article
 + Show details  Hide details

p.
245
–249
(5)
In this paper, a generalised Villeneuve type linear array distribution is developed, which permits the direct synthesis of discrete array distributions for high efficiency sum patterns of arbitrary sidelobe level and envelope taper. With the Dolph–Chebyshev distribution as the parent space factor, and the correct perturbation of these space factor zeros, the excitation efficiency and beamwidths are kept as close to their optimum values as is possible under the given sidelobe ratio and envelope taper conditions. The method is the discrete analogue of the generalised Taylor n̅distribution, used for continuous line source synthesis. Examples are given to illustrate the principal features of the distribution.
Intrinsic mode theory of conical corrugated horns
 Author(s): J.M. Arnold and A. Dendane
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 250 –256
 DOI: 10.1049/iph2.1989.0046
 Type: Article
 + Show details  Hide details

p.
250
–256
(7)
The application of the concept of intrinsic modes to the theory of propagation in conical corrugated horns is developed. An intrinsic mode is an exact solution of sourcefree Maxwell equations which satisfies the boundary conditions to a prescribed order of accuracy as the flare angle α becomes small. There exists an infinite number of intrinsic modes for a given structure and each one corresponds with a fixed local normal mode at every crosssection, to which it approximates asymptotically as α → 0. An intrinsic mode is given by a Fourierlike spectral integral which is uniformly valid, including the regions where the corresponding local normal mode is evanescent or in transition from propagating to evanescent. This spectral integral can be generated from knowledge of only one local normal mode at each crosssection, and numerical calculations show that the intrinsic mode based on the HE_{11} local normal mode is sufficient for many applications, including the calculation of crosspolar radiation.
Technical memorandum: Edge mode effect in the operations of waveguide twinslab ferrite phase shifter
 Author(s): J. Helszajn
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 257 –260
 DOI: 10.1049/iph2.1989.0047
 Type: Article
 + Show details  Hide details

p.
257
–260
(4)
The distributions of the electric and magnetic fields and power of the classic rectangular waveguide twinslab ferrite phase shifter, with one region magnetised along the positive ydirection and the other along the negative yd irection, are reexamined in the paper. It indicates that this type of device may quite often be phenomenologically described by a nonreciprocal edgemode effect, rather than, as is customary, in terms of circular variables. This model may be of value in the design of practical wideband devices. The presence of counterrotating magnetic fields at the two open faces of the ferrite region is also of note. The use of unequal oppositely magnetised sections is a possibility that has not received any attention so far.
Technical memorandum: Analysis of circular microstrip antennas with superstrate
 Author(s): K.M. Luk ; W.Y. Tam ; C.L. Yip
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 261 –262
 DOI: 10.1049/iph2.1989.0048
 Type: Article
 + Show details  Hide details

p.
261
–262
(2)
The spectral domain analysis is applied to study the effects of dielectric cover on a circular microstrip patch antenna. Numerical examples indicate that the resonant frequency of the patch is decreased considerably while the bandwidth is varied slightly.
Theoretical and experimental investigations of twodimensional waveguideexcited short backfire antenna structure
 Author(s): M.S. Leong ; P.S. Kooi ; Chandra ; T.S. Yeo
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 263 –268
 DOI: 10.1049/iph2.1989.0049
 Type: Article
 + Show details  Hide details

p.
263
–268
(6)
In this paper, the method of moments is utilised to investigate the radiation characteristics of the twodimensional version of a short backfire antenna excited by an input TEM mode. The theoretical predictions of the far field patterns and the input VSWR are in very good agreement with measurements performed on an actual prototype designed for the Xband. The technique has the virtue that it can be readily applied to the more useful rectangular geometry.
Uniqueness of numerical solutions to electric, magnetic and combinedfield integral equations for openended circular waveguides
 Author(s): J.R. Parkinson and M.J. Mehler
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 269 –275
 DOI: 10.1049/iph2.1989.0050
 Type: Article
 + Show details  Hide details

p.
269
–275
(7)
The moment method is used to solve the electric, magnetic and combinedfield integral equation, to determine the current distribution on a semiinfinite, openended, circular waveguide. A standard trianglefunction expansion is used to represent the exterior waveguide wall currents. The approximate nature of this current distribution is shown to lead to difficulties with the uniqueness of both the solutions associated with the electric and magneticfield integral equations. By examining the degree to which the boundary conditions are satisfied, the combinedfield integral equation is shown to yield superior results.
Lens antennas with amplitude shaping or sine condition
 Author(s): Samira Bishay ; S. Cornbleet ; J. Hilton
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, p. 276 –279
 DOI: 10.1049/iph2.1989.0051
 Type: Article
 + Show details  Hide details

p.
276
–279
(4)
The paper demonstrates the method of generic curve series to obtain the profiles of dielectric antennas, with design conditions either for the specification of the apertureamplitude distribution from a given source distribution, or for agreement with the Abbe sine condition. The method has already proved successful in the design of dual reflector antennas, and the extension to refractive media is shown to be straightforward. The method basically involves obtaining two equivalent expressions for a fundamental parameter from the usual optical equations and internal geometry of the lens, and obtaining agreement between them by a computational optimisation procedure using the series of curves. The parameter used in the paper is the internal segment of the ray within the lens. The method applies equally well to lenses with other a priori conditions such as afocal linear magnification or offaxis bifocality.
Erratum: Input impedance of rectangular microstrip antennas
 Author(s): A.K. Bhattacharjee ; S.R. Bhadra Chaudhuri ; A. Mukherjee ; D.R. Poddar ; S.K. Chowdhury
 Source: IEE Proceedings H (Microwaves, Antennas and Propagation), Volume 136, Issue 3, page: 279 –279
 DOI: 10.1049/iph2.1989.0052
 Type: Article
 + Show details  Hide details

p.
279
(1)
Most viewed content for this Journal
Article
content/journals/iph2
Journal
5
Most cited content for this Journal
We currently have no most cited data available for this content.