Pattern Diversity Circularly Polarized Antenna with Wide Axial-Ratio Beam

In this letter, a circularly polarized pattern diversity antenna with high gain and wide axis ratio beam performance is presented. The antenna can achieve an axial-ratio beamwidth of 150° using directional and dual-beam radiation, which has a high potential for application in satellite communications. The pattern diversity is achieved through a four-port hybrid feeding network, where the same signal input from different ports induces surface currents that generate co-directional or counter-directional radiation, resulting in directional beams and dual beams. At the same time, the circularly polarized beam coverage of these two radiation patterns is complementary so that overlapping radiation patterns can obtain broader beam coverage. The measured results show that the overlapping bandwidth of the two modes is 3.9% (3.22-3.35 GHz), with gains exceeding 8.5 dBic for the directional radiation mode and 6.2 dBic for the dual-beam radiation mode.