Design and fabrication of a GaN HEMT based amplifier for wideband applications

This paper reports design, fabrication and measurements of a wideband amplifier for UHF applications. A technology based on Gallium Nitride (GaN) transistor is used to design a class- AB amplifier with compact dimensions which can be employed as a driver stage for many UHF applications with wideband requirements. Wideband impedance transformers at input and output of the amplifier are implemented to achieve the wideband features including higher gain and efficiency. The designed amplifier is fabricated and then characterized to verify the design parameters and it has been observed that the simulated results are in agreement with the measured ones. Maximum RF output of 5W (37dBm) is demonstrated over frequencies ranging from 150-500 MHz with gain flatness of 2.5dB. Flatness of ±0.5dB is shown within 220-500MHz. The measured power gain is found to be above 17dB for the entire band.