Electromagnetic modes in conical transmission lines with application to the linearly tapered slot antenna

Author

Stockbroeckx, Benoît ; Vorst, André Vander

Author_Institution

Lab. d´´Hyperfrequencies, Univ. Catholique de Louvain, Belgium

Volume

48

Issue

3

fYear

2000

fDate

3/1/2000 12:00:00 AM

Firstpage

447

Lastpage

455

Abstract

A transmission line analysis of the bow-tie antenna and the linearly tapered slot antenna (LTSA) is presented. These structures belong to the class of conical transmission lines defined here in terms of conical coordinates. A complete set of solutions of the Helmholtz equation is obtained exhibiting TE and TM modes. Modal fields are expressed by Lame (1837) and Bessel-Schelkunoff functions. TE and TM eigenmode analysis is particularized to the bow-tie structure. Bow-tie antenna and LTSA are shown to be dual conical transmission lines by the image method and Babinet´s principle. The modes of LTSA are calculated on the basis of the results obtained for the bow-tie structure. The radiation pattern of the LTSA is computed as the integral of a closed-form expression of the dyadic Green´s function weighted by the modal electric field distribution over the slot aperture. The obtained dominant mode radiation patterns are validated by measurements from the literature. The radiation patterns of the first two-order modes are calculated and compared

Keywords

Green´s function methods; Helmholtz equations; antenna radiation patterns; eigenvalues and eigenfunctions; electric fields; integral equations; slot antennas; transmission line theory; Babinet´s principle; Bessel-Schelkunoff functions; Helmholtz equation; Lame functions; TE eigenmode analysis; TE modes; TM eigenmode analysis; TM modes; bow-tie antenna; bow-tie structure; closed-form expression; conical coordinates; conical transmission lines; dominant mode radiation patterns; dyadic Green´s function; electromagnetic modes; image method; integral; integral equation; linearly tapered slot antenna; measurements; modal electric field distribution; modal fields; radiation pattern; slot aperture; transmission line analysis; Antenna radiation patterns; Apertures; Closed-form solution; Distributed computing; Equations; Green´s function methods; Slot antennas; Tellurium; Transmission line antennas; Transmission lines;

fLanguage

English

Journal_Title

Antennas and Propagation, IEEE Transactions on

Publisher

ieee

ISSN

0018-926X

Type

jour

DOI

10.1109/8.841906

Filename

841906