Dual-Band and Shared-Aperture Fabry–Perot Cavity Antenna

This letter presents a novel dual-band and shared-aperture Fabry-Perot cavity antenna (FPCA) with high aperture efficiency (AE) and high port isolation, which operates in both S- and C-bands with a frequency ratio of 1:1.45. This antenna is composed of a partially reflective surface (PRS), a frequency selective surface (FSS), and a ground plane. A microstrip patch working at 3.45 GHz and a dipole working at 5 GHz are acted as primary radiator, respectively. To form two separate FP cavities, the FSS layer shows passband characteristic for low frequency and stopband characteristic for high frequency. Since two resonant cavities share the same PRS layer, the utilization rate of the proposed antenna has been significantly improved. This scheme can be used to design shared aperture antenna with any frequency ratio. To verify this design concept, an antenna prototype is designed, fabricated, and measured. The measured results demonstrate that the proposed dual-band shared-aperture FPCA has -10 dB impedance bandwidth of 3.42-3.47 and 4.94-5.05 GHz with the peak gain of 13.7 dBi (at 3.45 GHz, 77% AE) and 16.8 dBi (at 5 GHz, 74% AE), the isolation between two ports is better than 30 dB, which agrees well with the simulated ones.