Wide-band & high efficiency small cell PA characterized by dual band DPD for LTE carrier aggregation application

This paper reports on a 27.5 dBm wide band high efficiency InGaP/GaAs HBT two stage module operating at 1805 to 2170MHz for LTE small cell base station carrier aggregation applications. It uses a high linearity, low thermal resistance HBT flip chip process developed by Qorvo. The Psat of this device reaches 35dBm, with a gain of around 31dB, and a PAE of 55%. With a DPD (digital pre-distortion) system, this power amplifier can achieve an ACLR of -50dBc at 27.5dBm Pout with a power added efficiency of 30% for a 20MHz LTE modulation signal (PAR=7.5dBc) at 1.96GHz. Tested with dual band DPD system with 1.84GHz and 2.14GHz input signals and a total 40MHz bandwidth, this PA can deliver Pout 23.3dBm for each carrier with ACPR around -50dBc each, total efficiency of about 26%. To the best of authors knowledge, this is the first wide band small cell PA characterized by dual band DPD system.