A 40 watt C-band MMIC high power amplifier for space radar application exploiting a 0.25 m AlGaN/GaN on SiC process

This paper describes a C-band monolithic high power amplifier implemented with a 0.25 μm AlGaN/GaN HEMT process. The circuit has been designed for use in synthetic aperture radar antenna modules in space applications. The amplifier is made up of two stages: the final stage consists of eight devices for 9.6 mm of total periphery that are merged together to form a single power-bar. A quasi-inverse class-F regime for the HEMTs is implemented by harmonic tuning in order to achieve the best tradeoff between maximum output power and efficiency. When operating in pulsed mode with 50 μs pulse width and 10% duty cycle, the amplifier delivers about 40 watt with 21 dB of associated gain and 40% PAE over a 15% bandwidth centered at 5.4 GHz. The proposed MMIC HPA is a very valuable replacement for lower output power MMIC GaAs HPAs or hybrid HPAs, which are currently exploited at C-band for these applications.