A direct conversion IQ modulator in CMOS 65nm SOI for multi-gigabit 60GHz systems

This work describes the design and measurements of a direct-conversion IQ modulator operating in the 60 GHz frequency band, implemented in a 65nm CMOS SOI technology. It uses active power splitters combined with 90° phase shifters at the LO track that provide quadrature LO signals. The baseband I and Q signals are up-converted with n-MOS cold-FET mixers and power combining technique is employed at the RF 60 GHz output for transmission. The circuit has an output 1-dB compression point of -6dBm, a wideband operating frequency of 9 GHz around 60 GHz and a modulation bandwidth of 2.5 GHz. A 2 Gbps transmission data rate is demonstrated with QPSK and 16QAM modulation schemes showing 6.6% and 11% EVM, respectively. The power consumption is 24 mW for 1.2 V supply.