A 76 GHz GaN-on-silicon power amplifier for automotive radar systems

This paper describes the first demonstration of a 76 GHz gallium nitride (GaN) power amplifier (PA) on a silicon substrate. The PA microwave monolithic IC (MMIC) was fabricated by using AlGaN/GaN FET with a maximum oscillation frequency of 160 GHz and a breakdown voltage of over 50 V. For reducing transmission loss, we used a CPW line on the silicon substrate with low transmission loss of 0.5 dB/mm at 76 GHz. For precise design of the PA, a large signal model of the FET was developed. The developed CPW 3-stage PA exhibited an output of over 12 dBm with over 5 dB gain at 75-81 GHz.