Broadband Circularly Polarized Magnetoelectric Dipole Antenna and Array for K-Band and Ka-Band Satellite Communications

A circularly polarized (CP) magnetoelectric dipole (ME-dipole) antenna with a wide impedance bandwidth and 3 dB axial ratio (AR) bandwidth is proposed. The antenna is fed by a microstrip line and coupled through a modified cross-slot on the ground plane. Based on the conventional linearly polarized (LP) ME-dipole, the proposed electric dipoles and the coupling slots are modified to generate the CP radiation. Simulated results of the antenna element show an impedance bandwidth of 72.8% from 16.35 to 35.08 GHz and a 3 dB AR bandwidth of 39.2% from 21.53 to 30.07 GHz. To enhance the gain of the antenna for practical application, a 4 $\times $ 4 antenna array with full-corporate feeding network is designed, fabricated, and measured. The measured results show that an impedance bandwidth of 66.95% from 17.26 to 34.63 GHz and a 3 dB AR bandwidth of 41.1% from 19.25 to 29.25 GHz are achieved. The proposed antenna can be applied to K-band, Ka-band satellite communications or fifth-generation (5G) millimeter wave (mmWave) communications at n257 (26.5–29.5 GHz) and n258 (24.25–27.5 GHz) bands.