Scanning surface wave antennas--Oblique surface waves over a corrugated conductor

The existence of a surface wave which propagates across a corrugated metallic surface at an oblique angle with the teeth is investigated both experimentally and theoretically in this paper. Expressions are derived which give the variation of the wave velocity and amplitude with the change of wave direction. Experimentally measured values of the surface velocity compare favorably with the theory. The radiation pattern of an experimental antenna is given which demonstrates that a low sidelobe, narrow azimuth beam scannable to
\pm30
degrees with a cosecant-squared elevation pattern is attainable. A method of feeding this antenna to give a low silhouette, making the corrugated scanner antenna suitable for flush mounted applications is illustrated.