The application of GaN HEMTs to pulsed PAs and radar transmitters

Gallium Nitride (GaN) solid-state devices are emerging as a replacement for vacuum electron devices (VED) in radar systems. These solid-state devices have significant thermal and trapping effects that, although not ruling out their use, do complicate it. This paper evaluates several commercial GaN devices, using pulse testing, under conditions typical of modern, high-frequency radar systems. It is found that the I-V characteristics of these GaN devices vary with the pulse repetition frequency (PRF). Hence, the design methodologies employed must take this into account, especially when multiple-or staggered-PRF strategies are employed in the radar system.