Fully integrated Doherty power amplifiers for 5 GHz wireless-LANs

Fully integrated Doherty amplifiers have been developed for 5 GHz wireless-LAN (WLAN) applications. Through a new Doherty power amplifier circuit topology, the bulky Doherty in/output matching block including quarter-wave (lambda/4) impedance transformer can be fully integrated using capacitors, short micro-strip lines and bonding wires. To improve efficiency at a full power, without using the bulky input power splitter, a new input power driving concept is implemented by inserting lambda/4 impedance transformers at the inputs of the carrier and peaking amplifiers using the lumped elements. The amplifier based on InGaP HBT technology, shows an output power of 22.5 dBm and a power-added efficiency (PAE) of 21.3 % at an error vector magnitude (EVM) of 5%, measured with 54 Mbps 64-QAM-OFDM signals at 5.2 GHz. The proposed in/output matching topology allows the fully integrated Doherty amplifiers with a small size