Numerical solution of nonuniform surface wave antennas

Author

Cho, Se Hyun ; King, Ray J.

Author_Institution

Univ. of Colorado, Boulder, CO, USA

Volume

24

Issue

4

fYear

1976

fDate

7/1/1976 12:00:00 AM

Firstpage

483

Lastpage

490

Abstract

An integral equation is used to numerically study microwave surface wave antennas. The source is chosen as a horizontal magnetic line current which is placed parallel to a planar surface having a one-dimensional nonuniform surface reactance. The integral equation is numerically solved exactly taking full account of radiation from both the feed and the termination, and their mutual interaction. By varying the profile of the surface reactance and the antenna length, radiation characteristics such as directivity, beam width and sidelobe level are discussed. The optimum excess phase delay is found to be about $\\pi/3$ for an antenna length of $3\\lambda _{0}$ , gradually increasing to $\\pi/2$ for a length of $8\\lambda _{0}$ . When a feed transition in the reactance profile is used to achieve a good surface wave launching efficiency near the source, the first sidelobe can be reduced to less than-10 dB below the main beam level with little effect upon the directivity. Optimum reactance profiles are suggested for antennas from $3\\lambda _{0}$ to $8\\lambda _{0}$ long.

Keywords

Electromagnetic surface-wave antennas; Integral equations; Antenna arrays; Antenna radiation patterns; Antennas and propagation; Feeds; Integral equations; Phased arrays; Polarization; Reflection; Surface treatment; Surface waves;

fLanguage

English

Journal_Title

Antennas and Propagation, IEEE Transactions on

Publisher

ieee

ISSN

0018-926X

Type

jour

DOI

10.1109/TAP.1976.1141372

Filename

1141372