Broadband High-Efficiency Millimeter-Wave Power Amplifiers in 22-nm CMOS FD-SOI with Fixed and Adaptive Biasing

The design of broadband highly-efficient millimeter-wave (mm-Wave) Power Amplifiers (PA) in 22-nm CMOS FD-SOI (fully depleted silicon-on-insulator) is discussed. One design uses fixed biasing while the other utilizes an adaptive biasing network to improve its Power-Added-Efficiency (PAE) in power backoff. These designs aim to cover the key Fifth-Generation (5G) FR2 (Frequency Range 2) band (e.g., from 24.25 GHz to 43.5 GHz). In measurement, the PAs obtain very broadband 3-dB BW, ranging from 19.1 GHz to 46.5 GHz for the fixed-bias design and 18.8 GHz to 41.9 GHz for the adaptively biased design. The adaptively biased design is able to achieve enhanced output 1-dB compression point (OP1dB) and PAE@P1dB because of its adaptive biasing network. Measurements on the fixed-biased PA at 24/28/37/39 GHz yield max. PAE of 22.2/22.4/19.7/19.8%, and POUT,SAT of 14.9/15.3/14.7/14.7 dBm, with OP1dB of 11.8/11.6/12/11.6 dBm, and PAE@P1dB of 14.1/13.4/14.5/13.5%. Measurements on the adaptively biased PA at 24/28/37/39 GHz yield max. PAE of 20.1/15.2/10.3/7.9%, and POUT,SAT of 14.6/14.2/12.5/11.2 dBm, with improved OP1dB of 13.1/12.3/12.1/11.2 dBm, and PAE@P1dB of 19.1/14.4/10.3/7.9%. Data from body bias voltage VB on the PA performance is also presented.