A digitally modulated 60GHz polar transmitter in 40nm CMOS

A 60GHz polar Tx prototype implemented in 40nm CMOS includes a two-stage PA with an RF-DAC, an I-Q upconversion mixer, a 60GHz LO hybrid and a digital synchronization interface. Saturated output power is approx. 10dBm, while RF output and baseband input bandwidths are 9GHz and 1.2GHz, respectively. The linear RF-DAC resolution is 5 bits. EVM degradation and spectral mask out-of-band distortion appear at input powers higher than 6dB above P_-1dB. EVM is -19dB and -16dB at full rate, and -25.5dB and -22dB at reduced rates for QPSK and 16-QAM signals, respectively. The Tx consumes 75mW from 0.9V, and the core occupies 0.18mm² of the 2.38mm² testchip.