Challenges in designing 5 GHz 802.11ac WiFi power amplifiers

In this paper, we address the key challenges in designing 5 GHz 802.11ac WiFi power amplifiers (PAs). A critical objective in IEEE 802.11ac PA design is to achieve a very low error vector magnitude (EVM), especially when operating dynamically, while maintaining high power-added efficiency (PAE). In particular, the transient behavior and thermal characteristics of the PA need careful consideration during the design process. RFMD front-end modules (FEMs) achieve 19dBm linear output power at 1.8% dynamic EVM, with a PAE of 11% when using an 80 MHz 256-QAM MCS9 signal.