A Broadband Circularly Polarized Substrate Integrated Antenna with Dual Magnetoelectric Dipoles Coupled by Crossing Elliptical Slots

A broadband circularly polarized substrate integrated antenna with dual magnetoelectric (ME) dipoles coupled by crossing elliptical slots is proposed. The circular polarization is generated by the asymmetric crossing slots, and the parasitic dual ME dipoles are applied to improve the bandwidth and AR beamwidth. Simulation results show that the antenna obtains an impedance bandwidth of 12% over the band 27.6~31.1 GHz, a 3 dB axial-ratio (AR) bandwidth of 4.8% across the band 28.3~29.7 GHz, a 3dB AR beamwidth of 78° at the center frequency of 29 GHz, and the gain is higher than 5.1 dBic during the impedance bandwidth with the highest gain of 7.2 dBic at 30.2 GHz. Besides, the antenna based on the SIW has a low profile of 3 mm, which is attractive to array designs and integrated systems.