Dual-Band Circularly Polarized Stacked Square Microstrip Antenna with Small Frequency Ratio

Abstract

Abstract A probe-fed stacked square microstrip antenna for dual-band circularly polarized (CP) applications is presented. By properly selecting two square patches in the proposed design and loading a chip-resistance along the centerline of each square patch, dual-band CP radiation with small frequency ratio can be achieved. In order to prevent the second operating frequency from shifting to higher band which is resulted from a small air-gap between two substrates, an additional patch is introduced. Compared with conventional stacked dual-band CP antennas, the proposed antenna can achieve a smaller frequency ratio and has a larger tolerance of processing as well. Details of the proposed antenna design and experimental results for the dual-band CP performances are presented and discussed.