Chip Implementation of a 1.5-GHz Gain-Control Phase Shifter

This paper presents a 1.5-GHz RF gain-control phase-shifter fabricated in TSMC 0.18-mum CMOS process. The vector-synthesis topology is applied in this work to achieve a wide range phase-shift from 0deg 360deg for the processed RF signal. A gain-control buffer amplifier is added immediately after the phase-synthesizer to compensate the signal attenuation. The measured maximum attenuation is -21 dB for each of four attenuators which are the core circuits of the phase-synthesizer. The measured gain-control range of the buffer amplifier is around -16 dB at 1.5 GHz. The power consumption of the chip is 14.4 mW under 1.8 V power supply. The chip size is 0.74 times 0.68 mm².