A 1 V, 8 GHz CMOS integrated phase shifted transmitter for wideband and varying envelope communication systems

A novel 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, switching class F power amplifiers and wideband output combiners. The PS transmitter is implemented in a standard 0.18 μm CMOS technology, with 1 level of polysilicon and 6 levels of metallization, and occupies an area of 5000×1000 μm². It operates from a 1 V supply and provides 35 dBc adjacent channel power ratio for output bandwidths up to 50 MHz at 8 GHz. The combined class F PAs in the PS transmitter provide 20 dBm output power with a 38% power added efficiency.