Linear and Efficient Power Amplifier for WiFi

Abstract

CMOS technology is one of the feasible solutions to meet the world’s growing demand for high data rates because it offers the prospect of SoC at a low cost. But, the PA forms the major bottleneck in making SoC because the PAs in high data rate wireless communication systems have the requirement of high-efficiency and good linearity even at backed-off power levels. Currently, PAs are mostly of classes A and B. Both of these are linear, but peak efficiencies are only 50% and 78% respectively. This thesis focuses on implementing Continuous Class F (CCF) PA for WiFi 802.11n over the bandwidth 2.1 - 2.7 GHz, which meets the requirement of high efficiency and good linearity even at backed-off power levels. The CCF PA overcomes Class F’s disadvantage of limited bandwidth as well as maintains peak efficiency of 90.7% over the entire bandwidth. The designed PA has four main blocks: the driver, inter-stage matching, output network, and output stage. The procedure to implement each of these blocks is explained extensively in chapters 3, 4, 5, and 6. The layout of the chip is carried out in TSMC 40 nm, and the chip size is 1.4 mm2. From simulations, the CCF PA has a maximum efficiency of 30 % and EVM of -25 dB at 3 dB back-off across the bandwidth 2.1 -2.7 GHz. The tapeout of the chip is planned in March 2021. Later, the chip can be tested and simulation results will be validated. To the best knowledge of the author, this is the first CCF chip at 2.4 GHz band.