A goniometer for use with high-frequency circularly disposed aerial arrays

The paper describes the development of a high-frequency spinning goniometer for use as a direction finding unit on a wide-aperture circularly disposed aerial array. The factors governing the design of the goniometer are presented and three different prototypes are discussed, the third being a miniaturized version. Unlike previous goniometer designs, the beam forming network consists of delay lines and hybrid transformers mounted on the rotor assembly. This not only simplifies the electrical design and increases the operating frequency band but also enables the goniometer to work with arrays which exhibit standing wave ratios as large as 4:1 over the operating band. Previous designs of goniometer are limited to systems where the s.w.r. over the band remains below about 1.3:1. Areas for further improvements are discussed including alternative beam forming configurations.