5-GHz SiGe linearity power amplifier using integrated feedforward architecture for WLAN applications

This work presents a 5-GHz power amplifier (PA) based on a tsmc™ 0.35-μm SiGe heterojunction bipolar transistor (HBT) process. The PA adopts an on-chip linearizer as a feedforward element that cancels third-order distortion at the PA output. The PA achieves an output 1-dB compression point (OP_1dB) of 27 dBm, a power gain of 21.9 dB, and a power added efficiency of 31 %. Compared to a PA without a linearizer, the proposed PA improves the third-order distortion by 12 dB. For an OFDM/64-QAM signal, the error vector magnitude is minimized to 1.5 % at an output power of 18 dBm. The fabricated chip size is 2.17 mm² and is suitable for use in a highly integrated PA.