A C-band CMOS Transmitter with a 6-bit Phase Shifter and Power Amplifier for Phased Array Systems

This paper presents a 5-6.5 GHz transmitter with a 6-bit programmable phase shifter and a 3-stage power amplifier in 180 nm CMOS. The phase shifter consists of a 2-stage poly phase filter (PPF), an active vector modulator (AVM) and two inter-stage matching transformers. The measurement results show a RMS phase error of 1.0° to 1.88° and gain error of 0.13 dB to 0.3 dB over 5-6.5 GHz, covering 360° phase range at 5.625° resolution. Meanwhile, the transmitter achieves a gain of 27 dB, an output 1-dB compression point of 18.4 dBm, a saturated output power of 21.8 dBm and peak PAE of 12%. The core die area is 0.7mm$\times 2.5$mm.