Sectoral phase-mode beams from circular arrays

A simple technique for generating a set of broadband circular array phase-mode patterns with directional properties is presented. The directional beams covering each angular sector, share approximately the same far-field amplitude pattern, but are characterised by different nearly-linear phase slopes. The phase slopes correspond to omnidirectional phase modes of integer orders, but directional beams with half-integer phase-mode orders may also be implemented. It is shown that these beams, which are referred to as sectoral phase modes, may be incorporated in the design of a multimodal phase-comparison direction-finder in order to reduce its susceptibility to interference