Performance Evaluation of C-Band Class-AB Power Amplifier by Implementing Novel Sequencing Topology

This paper demonstrates design, fabrication and measurements of GaN-HEMT based C-band power amplifier (PA) for radar applications. The purpose of this effort is to design and develop GaN HEMT device (CGH40025F) based class-AB power amplifier by using nonlinear device model. The essential gate and drain ON-OFF sequence has been first time achieved by using the internal delays of -5volts traco (part# TRN3-2421SM) and 28 volts vicor (part# V28C28C100B2) dc-dc converters instead of sequential ICs and high current/low on-resistance power MOSFTETs. This technique makes the design simple and more reliable. The capacitor banks at input/output bias tees, impedance transformation both at the input and output of the amplifiers are implemented to achieve optimized parameters such as high RF output power, high power gain, Power added efficiencies (PAE) and good input/output return losses etc. The performance of proposed power amplifier is evaluated after successful design, fabrication and characterization. It has been observed that the simulated results are in good agreement with the measured values. The power amplifier designed using nonlinear model gave us 42dBm (16W) output power, power gain of 10.5 dB and 51.4% PAE. Moreover, the smooth power ON-OFF sequence has also been observed and measured successfully.