A 34- to 36-GHz Active Transmitarray for Ka-Band Tracking Radar Using 5G Tx/Rx Beamforming ICs: Design and 64-Element Demonstrator

An active transmitarray antenna is presented for Ka-band monopulse tracking radar in the 34–36-GHz range. A novel contribution is the application of commercial SiGe-based 5G beamforming chips in a large-scale naval radar array, demonstrating how developments in Ka-band communications can benefit radar technology. Three arrays of 0.77 m diameter each with 24368, 19424, and 7824 radiating elements are presented to compare amplitude-tapered, space-tapered, and hybrid-tapered designs. All designs achieve a sub-1° half-power beamwidth (HPBW), peak sidelobe levels (SLL) below −26 dB, and effective isotropic radiated power (EIRP) of 100 dBm at broadside with a ±60° grating-lobe-free scan range. Furthermore, a small-scale demonstrator is realized and presented that consists of an eight-layer printed circuit board (PCB) with
$8\,\, \times 8$
patch antennas on one side and a
$4\,\, \times 4$
open-ended waveguide (OEWG) feed-array with beamforming chips and integrated liquid cooling channels on the other side. After over-the-air calibration, the realized array achieves a peak EIRP of 56 dBm, a 12° HPBW, and the ability to scan to ±60° in the H-plane with
$\cos {}\theta $
scan loss and no grating lobes. E-plane scanning is achieved up to ±45° with
$\cos {}\theta ^{1.1}$
scan loss.