Modular Ka-Band Transmit Phased Array Antenna for SATCOM Applications

An active electronically scanned dual circularly polarized wideband transmit phased array antenna at Ka-band (27.5 GHz to 31 GHz) is proposed for satellite communications. The transmit (Tx) phased array module is designed with 256 dual-polarized antenna elements fed by 64 eight-channel Tx beamforming core chips on a multi-layered PCB. The antenna element has a stacked square-ring slotted patch structure with two orthogonally positioned proximity-feed ports. The dual-feed can be excited orthogonally for circular polarization (CP) and offers the flexibility to reconfigure the CP radiation, either left-handed CP (LHCP) or right-handed CP (RHCP). Furthermore, each 2×2 antenna cell can be arranged using sequential rotation manner to enhance the CP performance. The 256-element transmit array has an aperture size of 80mm × 80mm and a measured effective isotropic radiated power (EIRP) of 58 dBm, 6.2° half-power beam width (HPBW), sub 1 dB axial ratio (AR), and ±60° scanning range free of grating lobes. Scalability of the modular design is validated by implementing a 1024-element Tx phased array antenna with four 256-element array modules.