A novel technique for the analysis of the principal plane near-field patterns of conical and corrugated conical horns excited in the dominant mode based on the uniform geometrical theory of diffraction (UGTD) [1], [2] is presented. Numerical computations of the near-field amplitude patterns of a few typical conical and corrugated conical horns based on the GTD technique detailed here correlate well with the measured patterns, justifying the validity of the analysis presented. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.

M. S. Narasimhan

ANTENNAS, HORN

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GTD analysis of the near-field patterns of conical and corrugated conical horns

IEEE Transactions on Antennas and Propagation

An error in the geometrical theory of diffraction (GTD) near-field analysis of a conical horn published earlier is pointed out. This error is corrected, and the correct expression for the near-field patterns for the conical horn is presented. Computations based on the corrected formulas correlate better with results based on measurement as well as aperture integration technique [4]. Copyright © 1982 by The Institute of Electrical and Electronics Engineers, Inc.

A Correction to the Available Formula for the GTD Near-Field Patterns of Conical Horns

A geometrical theory of diffraction (GTD) analysis of the principal plane far-field radiation patterns of a hyperboloidal sub-reflector with a conical flange attachment (HWF) fed by a primary feed located at its focus is presented. While using the uniform geometrical theory of diffraction (UGTD) for evaluating the nonaxial fields, the method of equivalent currents is used in the axial region. In this paper, both the diffraction by the wedge formed between the hyperboloid and the conical flange and the diffraction by the edge of the flange are considered. While considering the diffraction by the edge due to the diffracted ray from the wedge in the H-plane, the slope diffraction technique has been used. The computed diffracted far-fields of a typical HWF illuminated by a high performance primary feed shows good agreement with the available measured data and with the results based on the method of physical optics (PO). The sharp cutoff and the low spillover characteristics of the HWF are highlighted by comparing its radiation pattern with that of a hyperboloid without a flange. Further, the effects of the different parameters of the HWF on its radiation pattern are also studied and plotted, so that these results can be utilized in the design of the HWF for a specific requirement. Copyright © 1981 by The Institute of Electrical and Electronics Engineers, Inc.

GTD Analysis of a Hyperboloidal Subreflector with Conical Flange Attachment

A geometrical theory of diffraction (GTD) analysis of the principal plane far-field and near-field patterns of a near-field Cassegrainian subreflector is presented. The uniform geometrical theory of diffraction (UGTD) [I] that drastically reduces the computation time has been utilized to analyze the subreflector in the form of a paraboloid illuminated by a plane wave. The numerical computations of the far-field amplitude and phase patterns of a typical paraboloidal subreflector based on the above technique correlate well with the results obtained by physical optics current integration, justifying the validity of the analysis presented. The GTD near-field analysis presented here is an improvement over that published earlier [2] and removes some of its limitations. Copyright © 1981 by The Institute of Electrical and Electronics Engineers, Inc.

GTD Analysis of Near-Field and Far-Field Patterns of a Parabolic Subreflector Illuminated by a Plane Wave

An analytically simple and sufficiently accurate solution for the eigenvalues of a class of spherical wave functions is presented. The class of spherical wave functions considered are modes in conical and quasipyramidal waveguides with perfectly conducting walls and hybrid modes in corrugated conical and quasipyramidal horns with an impedance boundary. The indicated solution has been first used to obtain in closed form eigenvalues of the class of spherical wave functions considered which are subsequently used as the starting values for evaluating the exact eigenvalues with a simple digital-computer based iterative algorithm. The digital-computer evaluation of the eigenvalues has been found to be very fast, since the starting values are close to the exact solution, irrespective of the flare angle of the radial waveguides considered. Further, some mathematical insight has been provided in order to explain why the asymptotic solution, which appears to be valid only for small flare angles, yields eigenvalues close to the exact one even for wide flare angle(s) of the radial waveguides. © 1973, IEEE. All rights reserved.

Journal	IEEE Transactions on Antennas and Propagation
ISSN	0018926X
Open Access	No