A 5.9-GHz Fully Integrated GaN Frontend Design With Physics-Based RF Compact Model

Abstract

This paper presents the design of a fully integrated high-efficiency and high-power RF frontend for the IEEE 802.11p standard in GaN HEMT technology. An embedded transmitter/receiver (Tx/Rx) switching scheme and a dual-bias power amplifier linearization technique are used to improve Tx efficiency and linearity. An accurate physics-based nonlinear large-signal device model is developed and used for the design, providing insight into the impact of the behavioral nuances of the GaN HEMTs on RF circuit performance. The fully integrated RF frontend is fabricated in 0.25- $\mu{\hbox{m}}$ GaN-on-SiC technology and occupies only 2 mm $\times$ 1.2 mm. The Tx branch achieves 48.5% drain efficiency at 33.9 dBm, $P{\rm sat}$ with 28-V supply. With orthogonal frequency-division multiplexing modulated signals, it achieves 30% average efficiency at 27.8-dBm output power while meeting the $-$ 25-dB error vector magnitude limit without predistortion. The Rx branch achieves $+$ 22-dBm output third-order intercept point with 3.7-dB noise figure at 12-V supply. The fully integrated high-efficiency and linear RF frontend designed with physics-based RF GaN compact models is demonstrated for the first time for future device-to-device applications.