A 0.5–6 GHz 360° vector-sum phase shifter in 0.13-µm CMOS

A 0.5-6 GHz CMOS vector-sum phase shifter with a full 360° phase range is presented. Employing phase-reversible variable gain amplifiers (VGAs), for simultaneous amplitude and polarity control, the phase shifter realizes a continuously tunable phase shift of 360° with only one DC control voltage and single-ended I- and Q-signals. A maximum gain of 11 dB is measured with a 2-dB gain variation over the 0.5-6 GHz band. The root-mean-square (RMS) amplitude and phase error are less than 0.95 dB and 7°. The measured in-band noise figure (NF) is better than 13 dB. Wideband input and output matching are also achieved throughout the entire band. Operating at 1.5 V, the entire circuit consumes 27.5 mW. To the best of the authors´ knowledge, it is the first time the phase-reversible VGA is used to realize a full-360° vector sum phase shifter, which eliminates the need for an input balun and a complicated control circuit.