A 25 GHz Active Phase Shifter Using 10 bit Cartesian Control
This paper presents an active RF phase shifter, targeted towards 5G wireless systems, which uses an IQ vector modulator (IQVM) topology with a 10 bit cartesian codebook. The circuit is designed using 45 nm CMOS SOI technology. To generate the I and Q basis vectors for the IQVM, a tunable polyphase filter with a novel tuning mechanism is used, which allows operation over an octave of a frequency range, from 22 GHz to 40 GHz. The RF bandwidth of the proposed phase shifter is 2.5 GHz and can provide in excess of 8 dB of fine gain control over 360 degrees of phase shift. Active area occupied is 0.2 square millimeter. The total DC power consumed from 1 V supply is 36 mW.