A LEO Satellite Mounted 256-Element 19 GHz CMOS Phased-Array Transmitter With On-Chip Amplitude and Phase Monitor

This article presents a 256-element CMOS active phased-array transmitter (TX) that works in Ka-band downlink for low earth orbit (LEO) small satellite communication (SATCOM) applications. The phased array adapts an on-chip monitor circuit which can be used to detect the amplitude and phase for calibration. The TX chip’s output 1 dB compression point (OP1dB) is 11dBm and saturated output power (Psat) is 12dBm for every path. The phased array can support single circular polarization (CP) and dual circular polarization modes. The maximum effective isotropic radiated power (EIRP) for the single CP wave can reach 64.6 dBm under a power consumption of 37.4W. The error vector magnitude (EVM) of this work can support 256APSK modulation in both single CP mode (at 2 Gbaud symbol rate) and dual CP modes (at 250Mbaud symbol rate). As for beam steering ability, the phased array can cover a beam angle of ±66°. Compared to the conventional TX, this work has a larger beam angle and EIRP without sacrificing too much power consumption.