Wide bandgap transistor amplifiers for improved performance microwave power and radar applications

The generation of high RF output power, on the order of 100s to 1000s of watts necessary for transmitters for radars and wireless communications systems, remains a difficult challenge for semiconductor devices. RF power devices fabricated from standard semiconductors such as Si and GaAs are limited in the RF output capability by the inherent breakdown voltage of the semiconductor material. Recently, the development of wide bandgap semiconductors, such as SiC and GaN and related heterostructures, offers the potential to fabricate transistors with an order of magnitude improved RF output power compared to traditional devices. The wide bandgap semiconductor transistors offer the potential to fabricate high power transmitters for radars and communications systems, thereby permitting full semiconductor realization of advanced systems. However, the wide bandgap semiconductor devices currently suffer from several physical effects that are limiting the RF performance, and thereby, their application. These limitations are discussed and solutions presented.