Wide-Angle Scanning Dual-Beam Dual-Circularly Polarized Phased Array for Satellite Communications

Satellite communications generally require antennas with circular polarized (CP) performance and employ multiple beams to enhance communication capacity. Achieving CP necessitates antenna elements with orthogonal polarizations possessing a 90° phase difference. Both phase error and amplitude error in orthogonal polarization will degrade polarization performance. The implementation of a multibeam phased array typically increases the complexity of the PCB fabrication. To overcome these limitations, this work introduces improved equivalent magne to-electric dipole element capable of generating orthogonal polarizations with high purity and balanced amplitude over wide beamwidths. And the traditional Г-shaped feed structure is rede signed into a cross-shaped configuration, eliminating the back-drilling requirement associated with staggered vias in Г-shaped feed structures. To enhance bandwidth, the following sequential measures are implemented: First, disrupting inter-element resonances by introducing slots in the PCB patch and strategically placing shorting vias. Second, forming a shielded cavity around the hybrid coupler with shielding vias to suppress mutual coupling preceding the coupler. Through an optimized PCB stack-up, a wideband, wide-angle-scanning, du al-circularly-polarized (dual-CP), and dual-beam phased array for satellite communications has been realized using only three lamination cycles. The final design achieves a scan coverage of ±70° while maintaining an axial ratio (AR) below 3 dB across the entire scanning range.