Design and simulation of an S-Band tunable solid-state power amplifier as an RF injector into a miniature ECR ion source

A continuous-wave solid-state-based power amplifier is designed and simulated in this paper to work as an RF injector into an ECR ion source chamber. Employing a solid-state radio frequency power amplifier, instead of microwave tubes, leads to having higher efficiency, lower price, compact size, and longer lifetime. Also, a modular design can be achieved for designing higher output power by repeating lower power sources and combining them. The proposed solid-state source can deliver more than 200 W power to the ion chamber with a single high-power transistor. The selected Doherty high-power transistor is internally matched to 50 ohms and does not need a bias sequence circuit. Two gain stages are applied to drive the high-power transistor. The designed RF source is simulated using the Advanced Design System (ADS) based on the measured scattering parameters of components. Simulations show an output power of more than 57 dBm with a tunable frequency bandwidth from 2.3 to 2.5 GHz.