Transmission of Signals With Complex Constellations Using Millimeter-Wave Spatially Power-Combined CMOS Power Amplifiers and Digital Predistortion

This paper reports the generation, amplification, and radiation of modulated signals at 45 GHz using a single-chip CMOS power amplifier coupled to a 2 × 2 antenna array. Using digital predistortion, complex constellations were demonstrated for wide modulation bandwidth, which allows high data rates to be transmitted in a spectrally efficient manner. After predistortion, a 98-MS/s 1024-QAM signal with peak-to-average power ratio of 7 dB was demodulated with an error vector magnitude of 1.3%. The measured equivalent isotropically radiated power was 26.2 dBm. The corresponding average RF power produced by the CMOS chip, considering a simulated antenna gain of 12 dB, was 14.2 dBm.