Design and characterization of a broadband SiC power amplifier

Due to the proximity of military and civilian bands at the relevant frequencies low frequency radar and EW systems needs amplifiers which combine a broadband coverage, a high output power and efficiency with a good linearity. The wide bandgap semiconductors SiC and GaN offer an impressive RF and microwave power-frequency capability [1] but relatively few SiC transistor amplifiers have been designed for frequencies below 500 MHz. Recently, however, F Villard et al. described a SiC MESFET with an output power of 37,5 W, a gain of 8 dB, an efficiency in class AA-B of 55% at 500MHz [2]. The IMD3 level with 10-dB back-off from the 1 dB compression point and a 1 MHz frequency offset between tones was – 35dB. Using 10W Lateral Epitaxy SiC MESFET power transistors fabricated at AMDS AB we have done a preliminary design and characterization of a wideband 100 – 500 MHz SiC-based power amplifier. The amplifier is designed for a broadband multifunction EW system.