A miniaturized high-efficiency GaAs HBT power amplifier used in TD-SCDMA handset application

This paper is the first to report a monolithic HBT power amplifier for TD-SCDMA cellular phones which achieves a high efficiency and linearity. The two-stage MMIC integrates input and interstage matching circuits, and active bias circuits in a single chip with a chip size as small as 0.91×0.98 mm². The amplifier obtains a power-added efficiency (PAE) of 43% (16%) and 28.5 dB (23.8 dB) of the gain at the high and low operation mode under the 3.4 V supply. In addition, the adjacent channel leakage power is below -39 dBc and -48 dBc at 1.6 MHz and 3.2 MHz offset respectively with QPSK modulation. The MMIC offers the potential both for low cost production due to small chip size, stable voltage supply, and high performance at the same time.