A multipole expansion technique to study radiation from aperture antennas in the form of an open-ended waveguide-horn is presented. Particular attention is paid to dual-mode and corrugated circular horns. The radiation pattern of these feeds, derived in terms of multipole moments, is in the form of an algebraic series which converges very rapidly. Further, based on the multipole-expansion technique presented, the far-zone fields of an axially-symmetric aperture-fed paraboloid are obtained in closed form. It is demonstrated that there is a drastic reduction in computer time by using this technique instead of the conventional numerical integration procedure for calculating the far-zone fields of the paraboloid. Copyright © 1976 by The Institute of Electrical and Electronics Engineers, Inc.

M. S. Narasimhan

MATHEMATICAL TECHNIQUES - Convergence of Numerical Methods

Waveguide components

ANTENNAS, HORN

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IIT Madras

Radiation from aperture-fed paraboloids employing source-multipole expansions

IEEE Transactions on Antennas and Propagation

The uniform geometrical theory of diffraction (UGTD) has been applied successfully to analyze the near-field patterns of a prime-focus paraboloid. In order to establish the validity of the analysis, near-field amplitude and phase patterns have been computed over the principal planes at several observation distances for a typical prime-focus paraboloid. These calculations compare very favorably with the corresponding results obtained numerically with the aid of Silver's near-field aperture integration formula. Copyright © 1981 by The Institute of Electrical and Electronics Engineers, Inc.

GTD Analysis of the Near-Field Patterns of a Prime-Focus Symmetric Paraboloidal Reflector Antenna

A multipole expansion technqiue is developed for calculating the co-polar and cross-polar radiation patterns of a prime-focus paraboloid fed by a dominant-mode rectangular waveguide feed. Initially, the feed radiation pattern is expressed in terms of electric and magnetic multipoles of different orders which are subsequently used to obtain the secondary radiation patterns (co-polar and cross-polar) in explicit closed form in the form of a rapid by a converging algebraic series. The validity of the analysis is effectively demonstrated by calculating the co-polar and cross-polar patterns of a typical paraboloid and comparing and results with calculations based on the direct numerical integration of the physical optics currents induced on the reflector surface. Copyright © 1980 by The Institute of Electrical and Electronics Engineers, Inc.

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