Lightweight and deployable phased arrays are important in Small-Satellite (Small-Sat) constellation systems to reduce price and increase link distance. This article proposes a Ka-band deployable active phased-array TX on a 4-layer liquid crystal polymer (LCP) board for a lightweight and high stowage rate solution to break through the trade-off between high antenna aperture size and small form factor in phased arrays. This article describes detailed designs of the phased array and its building blocks with the proposed 4-layer LCP substrate structure. Assembled with the beamformer ICs (BFIC), a Ka-band $8 \times 4$ -element deployable active phased-array TX on the 4-layer LCP substrate is fabricated. The proposed deployable phased-array TX can steer the beam from −50° to 50°. The phased-array TX can drive 32-APSK DVB-S2 signal with a −28.7 dB EVM as well, revealing that the deployable phased-array TX performs with high phased-array performance. Furthermore, the TX achieved the lightest and thinnest phased array with 0.96 kg/m2 areal mass and 0.9 mm thickness. This groundbreaking research sets the stage for the realization of affordable and user-centric satellite communication (SATCOM) in low-earth orbit (LEO).
