A Broadband High-Power Amplifier Design for Remote-Controlled IED Jammer Applications

Abstract

Nowadays, the demand for broadband high-power power amplifier (PA) is on the rise due to electronic warfare (EW) applications such as remote-controlled improvised electronic device (IED) jammer and active electronically scanned array (AESA) radar.

In this thesis, hybrid-type multi-octave high-power PAs using Gallium nitride (GaN) –high electron mobility transistor (HEMT) are designed for IED jammer application. In order to realize both high-power and broadband characteristics, 2 broadband PAs with lower power level are combined in parallel to compensate for power degradation due to bandwidth enhancement.

In the first phase of the design process, 1-way broadband PA was designed using harmonic resistive loading for bandwidth enhancement. The fabricated 1-way module exhibited more than 45 dBm saturated output power across 2.5 to 6.5 GHz bandwidth, verifying that the employed topology is suitable for S/C-band high-power applications for IED jammer.

In the final stage of the design process, 2-way broadband high-power PA was designed by combining 2 1-way PAs designed from the previous stage. Instead of employing conventional Wilkinson combiner for power combining, multi-section Wilkinson combiners including matching networks within are employed for the reduction in the overall size and bandwidth enhancement. In addition, it has been confirmed that inevitable removal of some shunt resistors inside Wilkinson combiners due to limitation in line bending does not lead to serious degradation in isolation characteristics, making it possible to remove some resistors. The fabricated 2-way module exhibited more than 42 dBm saturated output power across 2.0 to 7.0 GHz bandwidth, showing great improvement in bandwidth over conventional PA combining method using 1-section Wilkinson combiner.