High-Gain Circular-Polarization Microstrip Antenna Based on TM90 Mode

A novel high-gain circular-polarization microstrip antenna is proposed by combining a rectangular patch operating in TM90 mode with a up-loading tilted-dipole array. Current interference and differential-feeding technique are adopted to achieve a high broadside gain and desirable bandwidth for the patch in TM90 mode. The up-loading dipole array serves as a linear-to-circular polarization converter. A simulated gain of15.9 dBi has been achieved with a impedance bandwidth (S11 <; -10dB) of 8.1% (11.76-12.79 GHz) and a 3-dB AR bandwidth is 6.6%(11.76-12.55GHz). The antenna has a simple structure with low profile, which can be made directly with low-cost standard printed circuit board (PCB) process.