A BROADBAND INVERTED DOHERTY POWER AMPLIFIER FOR IEEE 802.11b/g WLAN APPLICATIONS

摘要

A broadband inverted Doherty power amplifier (IDPA) is proposed in this article. To achieve the tradeoff between efficiency and operation bandwidth, an optimized output matching network and offset lines are used to design the load network of the proposed power amplifier (PA). For experimental verification, a conventional IDPA and a class-AB biased balanced PA have been implemented. In addition, a 64-QAM modulated signal with 24-MHz channel bandwidth are applied as excitation. According to experiment results, the proposed Doherty power amplifier can keep power-added efficiency (PAE) higher than 31% from 2.4 to 2.5 GHz with 0.5 dB output-power flatness at 27-dBm output power. The PAE of the proposed PA is 16.4% and 4.2% higher than the balanced PA and the conventional IDPA respectively. In addition, the linearity of the proposed PA is improved effectively.