Two designs of bidirectional same-sense circularly polarized antennas with cavity structures

摘要

Two antennas with bidirectional same-sense circularly polarization are presented in this paper. The first antenna consists two back-to-back patches with a common ground and a stepped microstrip feeding line. The two patches are behaving as a cavity by coupling through a slot on the common ground, providing bidirectional patterns with the same-sense circular polarization. Based on the dual-patch cavity structure, another cavity antenna with crossed slots on the front and back sides are proposed as the second antenna, also providing bidirectional circular polarization with the same sense. Especially, the second antenna is designed on both sides of only one layer of substrate, with the merits of low cost and easy fabrication. By numerical simulation, we studied the bandwidth and axial ratio properties of two proposed antenna with cavity structures.