CMOS wireless phase-shifted transmitter

A fully integrated phase-shifted (PS) transmitter is presented in this paper. The PS transmitter employs switching power amplifiers, operates without mixers, and provides an intermodulation distortion-free output spectrum, making it a suitable choice for mobile communication systems. The RF blocks of the PS transmitter include a local oscillator, phase shifters, and switching class-F power amplifiers with wide-band matching networks. The PS transmitter is implemented in a standard single-polysilicon, six-metal 0.18-μm CMOS technology and occupies an area of 3 mm². It operates from a 1-V supply and provides better than 42 dBc adjacent channel power ratio with an output bandwidth of 50 MHz at 8 GHz. The PS transmitter RF front-end provides 22 dBm of average output power with a 38% average power added efficiency.