A Wideband Distributed Amplifier Employing an Envelope Tracking Technique

Abstract

This letter presents a wideband distributed amplifier employing an envelope tracking (ET) technique for high efficiency and linearity. By applying the ET technique to the distributed amplifier after linearity optimization, the distributed amplifier's defects such as low output power and low efficiency can be overcome and high efficiency and linearity can be achieved. For verification, the distributed amplifier is designed using two Nitronex NPTB00025 GaN HEMT devices and tested with LTE signals at 2.6 GHz. From the tested results at an average output power of 37 dBm (10 dB back-off power), the proposed circuit shows an adjacent channel leakage ratio (ACLR) below -45 dBc at +/-5 MHz offset, with a gain over 14.1 dB and a power-added efficiency (PAE) over 21.9% over a 300 MHz bandwidth.