Load modulation power amplifier with lumped-element combiner for IEEE 802.11 b/g WLAN applications

Abstract

A new monolithic microwave integrated circuit power amplifier for 802.11 b/g wireless local area network (WLAN) has been implemented using the load modulation concept of a Doherty amplifier. The lambda/4 transmission line for the load modulation circuit of the carrier amplifier is replaced by a lumped element based pi-network, which dual functions as an Output matching network, simultaneously. This amplifier shows that error vector magnitude is about 4.6% and power added efficiency (PAE) about 31.8% at P-out of 19 dBm for a 802.11g 64QAM signal. PAE of the power amplifier is about 49.6%, and adjacent channel leakage ratio below 37.2 dBc at 11 MHz offfset at Pout of 23 dBm for the 802.11 b complementary code keying signal.