Integrated Power Combining and Amplification for Compact S-Band Radar Transmitters

Abstract

This paper deals with one of the major problems in high power S band radar transmitters by discussing the design, simulation, fabrication, and validation of a compact, high performance Wilkinson type power divider with amplifier impedance matching network. Till now, traditional Wilkinson Power Dividers (WPDs) tend to focus on isolation and return loss but are poor in amplitude balance throughout the wide frequency ranges especially in high power and space limited applications. The architecture proposed is applicable for a 1 kW S-band radar transmitter and focuses on minimal amplitude imbalance (≤0.75 dB), compact, return loss better than −12 dB. When simulations were conducted using Advanced Design System (ADS) software, performance was shown to be strong with insertion loss between −12.18 dB and −12.50 dB, return loss more than −18.65 dB, and isolation more than −25 dB in the bandwidth, 2.7–3.0 GHz. The design was built using a Rogers RT/Duroid 5870 substrate, the design utilized a 75W PH2731-75L RF transistor with optimized impedance matching to have a high power dissipation. Simulations came relatively close to measurement results, which confirmed the effectiveness of the design. This work helps to build compact and efficient RF front end modules for radar that can be upgraded from the insertion loss and future applications wise.