Design of Class AB Power Amplifier to Enhance Detection Range of S-band Radar Module Using GaN HEMT

Wireless devices have become integral to our daily lives, from cellular to IoT devices influencing the living style of a larger population with technological innovation. Consequently, the ongoing advancements in their respective building blocks aim to enhance overall performance. A critical element in all wireless systems is the power amplifier responsible for driving the antenna. This study aims to improve the detection range of our earlier S-band motion detection system, which utilized a microwave radar sensor and achieved range extension through the use of a directional reflector. To further enhance the range, an optimized high-frequency power amplifier design is proposed. The design employs the CREE GaN high-electron-mobility transistor (HEMT) CG2H40010, capable of delivering high output power with efficiencies exceeding 60% at 40 dBm. The design accounts for substrate losses, achieving a return loss better than -23 dB. Impedance matching to a standard 50-ohm system is accomplished using input and output microstrip networks. The performance of these networks is validated through simulations using the momentum method in the Advanced Design System (ADS) software. Beyond its various applications, integrating this amplifier into radar module transmitters is expected to increase the radar detection range by up to 120%.