50W C-Band GaN MMIC Power Amplifier Design

This paper presents a 50W C-Band GaN MMIC Power Amplifier using 0.25 mu m GaN/AlGaN HEMT based process from United Monolithic Semiconductor (UMS). It is a 2-stage circuit which achieves a power level greater than 48 dBm over 400MHz bandwidth centered around 5.35 GHz with a large signal gain of 25dB. The amplifier has been designed for high efficiency by optimizing fundamental and harmonic impedances and ensuring low loss matching networks. The simulated efficiency of the amplifier is 48 - 53 % over the band. The circuit core occupies a small area of 26.8mm(2) (4.7mm X 5.7mm). The power density over the full chip area is 2.57 Watt/mm(2). Further, the design satisfies the de-rating condition essential for space applications.