The Novel W Parasitic Strip for the Circularly Polarized Microstrip Antennas Design and the Mutual Coupling Reduction between Them

摘要： This paper presents a novel W shaped parasitic strip to design the circularly-polarized (CP) simultaneous transmit and receive (STAR) antennas and reduce the mutual coupling (MC) between them. By disturbing the current fields and inducing the current distribution on the antenna patches, the CP radiation and MC reduction are achieved. The designed CP antennas have 30 MHz 10-dB impedance bandwidth, 16 MHz 3-dB AR bandwidth and approximate 5.08 dBic peak CP gain. This technique also reduce the MC from ?7 dB to ?50 dB when the antennas are placed with a 0.18 λ0 center-to-center distance and a 0.033 λ0 edge-to-edge distance, where λ0 is the free-space wavelength. When achieving the MC reduction, the antenna radiation pattern restores to that of the isolated antenna. Furthermore, the antenna CP gain and efficiency is improved comparing those of the antenna without the parasitic strip or the classic corner cut CP antenna.