A 2-6 GHz fully integrated tunable CMOS power amplifier for multi-standard transmitters

A tunable power amplifier (PA) from 2.1 GHz to 6.0 GHz is presented for multi-standard radios. The proposed multi-band PA can tune the output impedance to 50 ¿ over a wide frequency range, so external isolators following PAs can be eliminated. The PA is implemented by using a 0.18 ¿m CMOS process, and the supply voltage is 3.3 V. Over all of the frequency range, the PA realizes output return loss S
₂₂
of smaller than -8 dB, power gain of larger than 12 dB, output 1-dB compression point of larger than 15 dBm.