A small hemispherical helical antenna array for two‐dimensional GPS beam‐forming

Abstract

A small hemispherical helical antenna array with multibeam output for GPS beam‐forming is designed and characterized. A Butler matrix beam‐forming network is designed to provide four spatial beams in a two‐dimensional directional space. The original design of the hemispherical helical antenna elements is modified in order to match it to the system impedance. Our study shows that even after an ∼30° scan from the normal direction, the maximum change in beam width is only 6°, the maximum change in axial ratio is 1.4 dB, and the maximum change in power gain is 1.1 dB. These characteristics indicate that the array can be potentially used for GPS beam‐forming.

A hemispherical helical water antenna array for directional high-gain radiation

“…But the cylindrical helical structure has a high profile and poor stability. A hemispherical helical antenna with higher stability and lower profile has been proposed and applied in an antenna array [15,16]. Studies have shown that hemispherical helical antenna has good radiation characteristics and are suitable for forming four-element arrays to achieve beam control.…”

“…Based on the work [15,16], a hemispherical helical water antenna is proposed in this paper. It has a more stable structure and can be conveniently conformed on the surface of a sphere.…”