A compact channel patch antenna with reconfigurable circularly polarized pattern for mobile satellite communications

A compact dual-band circularly polarized antenna with a characteristic of pattern reconfiguration is proposed for S-band satellite handsets. The antenna works as a patch antenna in a channel shape with no ground beneath reaching an overall size of 0.55 & lambda; x 0.14 & lambda; x 0.1 & lambda;. The dual-band performance is realized through multi-branch slots of the patch. The antenna mainly consists of a channel metal patch, a channel dielectric, and a simple feeding network. The overall shape of slot can be changed by the PIN diode on the patch to adjust the surface current direction, which in turn achieves 180 degrees switching of the left-hand circularly polarized radiation beam direction. In addition, by combining the quadrifilar helical antenna, which is switchable in the end-fire beam direction, the designed antenna can realize the switching of four main beam directions to achieve 360 degrees 3D spatial coverage. The proposed antenna is fabricated and measured to verify the proposed design. The test results show that the designed antenna obtains circularly polarized radiating characteristics in S-band with the center frequency of 1.98 GHz and 2.2 GHz, and the test results and simulation results are basically consistent, which indicates the superior performance of the designed antenna.