A K-Band 4-Beam Phased Array Transmitter in Only 5-Layer PCB Enabled by Silicon-Assisted Beam-Combining Network for SATCOM

Conventional fully-connected multi-beam phased arrays (FC-MBPA) face severe integration challenges due to complex beam-combining networks (BCN), leading to high complexity and over 10 PCB metal layers. To address this, we propose a scalable silicon-assisted architecture. A 16-to-4 beam-combining chip with high isolation is developed in 65-nm CMOS process, which can be switched to K- or Ka-band. As a proof of concept, a K-band 4-beam 16-element transmitter in only 5-layer PCB is presented. The prototype achieves ±30° beam scanning, <-31.6 dB inter-beam coupling and >17.1 dB cross-polarization discrimination (XPD). The array can also deliver 45.5 dBm maximum EIRP and 200-MSps 16-QAM signal with 3.56% EVM. With >60% reduction in PCB thickness, the proposed architecture lowers system complexity and antenna feeding loss, offering a cost-effective solution for scalable SATCOM systems with 4 beams and beyond.