A 2 W GaAs doherty amplifier for 5.5–5.6 GHz applications

In this paper the design of a 2 W uneven C-band Doherty power amplifier is presented. The Doherty PA is designed to achieve high efficiency for digitally modulated signals with high peak to average power ratio (PAR) used in wireless local area network (WLAN) systems around 5.6 GHz. The Doherty amplifier has been designed using two equal sized GaAs devices for the main Class- AB and peaking Class-C amplifiers. An uneven power divider is used at the input to deliver more input power to the peaking PA. The measured maximum output power of the realized uneven Doherty PA is 34 dBm with 50 % peak drain efficiency (43 % of power added efficiency). The power added (drain) efficiency is higher than 25 % (30 %) up to 6 dB of back-off. Moreover, an adjacent channel power ratio (ACPR) of -30 dBc has been measured using a digitally modulated signal of 10 MHz bandwidth.