Radiation of an aperture antenna covered by a spherical-shell chiral radome and fed by a circular waveguide

Author

Li, Le-Wei ; Leong, Mook-Seng ; Kooi, Pang-Shyan ; Yeo, Tat-Soon ; Qiu, You-Lin

Author_Institution

Dept. of Electr. Eng., Nat. Univ. of Singapore, Singapore

Volume

46

Issue

5

fYear

1998

fDate

5/1/1998 12:00:00 AM

Firstpage

664

Lastpage

671

Abstract

This paper presents a full-wave analysis of the radiation characteristics of an aperture antenna that is flush-mounted on a ground plane and fed by a circular waveguide supporting the dominant TE₁₁ mode. The antenna is covered by a dielectric hemispherical chiral radome. Huygen´s equivalence principle and the image theory are utilized to simplify the problem. The magnetic dyadic Green´s function for the three-layered geometry is formulated and applied to analyze the radiated electromagnetic fields outside the chiral radome. Both the exact and approximate expressions of electric fields valid for the Fresnel and Fraunhofer zones are obtained using the spherical vector wave functions and their approximations in the far zone. Various chiral materials are assumed and computations of antenna parameters are carried out. The effects of the dielectric chiral radome on the radiation power patterns, sidelobe levels, and 3-dB beamwidths are also discussed numerically

Keywords

Green´s function methods; antenna feeds; antenna radiation patterns; aperture antennas; approximation theory; chirality; circular waveguides; dielectric devices; electromagnetic fields; radomes; wave functions; 3-dB beamwidths; Fraunhofer zone; Fresnel zone; Huygen´s equivalence principle; TE₁₁ mode; antenna parameters; aperture antenna radiation; approximate expression; chiral materials; circular waveguide; dielectric hemispherical chiral radome; electric fields; exact expression; far zone; full-wave analysis; ground plane; image theory; magnetic dyadic Green´s function; radiated electromagnetic fields; radiation characteristics; radiation power patterns; sidelobe levels; spherical vector wave functions; spherical-shell chiral radome; three-layered geometry; Aperture antennas; Dielectrics; Electromagnetic analysis; Electromagnetic fields; Electromagnetic waveguides; Geometry; Green´s function methods; Magnetic analysis; Planar waveguides; Tellurium;

fLanguage

English

Journal_Title

Antennas and Propagation, IEEE Transactions on

Publisher

ieee

ISSN

0018-926X

Type

jour

DOI

10.1109/8.668909

Filename

668909