Beamwidth-Reconfigurable Circularly Polarized Slot Antenna Based on Half-Mode Substrate-Integrated Waveguide

Beamwidth-reconfigurable antennas are useful for the intersatellite link of low earth orbit formation flying and constellation, as they prevent unauthorized satellites from eavesdropping. In this article, a circularly polarized slot array antenna based on half-mode substrate-integrated waveguide (HMSIW) K-band beamwidth reconfiguration is proposed using new radio frequency (RF) switch structure pair modified −45° +45° linearly HMSIW arrays dual operation single-pole double-throw (SPDT)/a power divider (PD) easy integration with other components, respectively. The RF consists T-junction PD, λ/4 lines, beam lead PIN diodes current control resistors without DC block circuit consumption size reduction. −45°/+45° providing linear circular polarizations (LP CP, respectively) operated CP. use short-circuited termination instead dissipative results in easier components because 16 radiating slots consume most input power. dimension beamwidth-reconfigurable including bottom metal layer 157.2 × 23.3 0.254 mm3 (12.5λ0 1.86λ0 0.0202λ0). SPDT shows insertion losses 1.8–2.3 16.7–24.2 dB an isolation 20.9–33.4 both outputs within 10-dB bandwidth. PD has loss 3.9–4.8 dB. one- two-antenna modes CP provide gains 9.44 6.99 dBic, axial ratios 2.24 3.47 dB, horizontal beamwidths 35.8° 78.2°,