Design & Development of 2KW Front-End Circulator-Switch Assembly for Space Applications

Ferrite based duplexing circuits are very important component used in microwave radars to provide a low loss path between the high power transmitter & antenna and between the antenna & receiver. It protects the sensitive receiver from any leakage which may come from the transmit path when the high power microwave energy is being transmitted to the antenna. It is also required to provide fast switching between transmit and receive path at PRF (Pulse Repetition Frequency at which Radar is operating) rate providing very low-loss insertion in both transmit and receive path. This paper presents the design, development and test results of a high power Circulator-Switch Assembly (CSA) operating at 9.6 GHz ± 300 MHz frequency. The measured value of insertion loss is better than 0.2 dB and 0.6 dB in transmit and receive path, respectively, with more than 65 dB isolation between transmit and receive path. 1.7 µsec of switching speed has been achieved using MOSFET based switch driver circuit. The developed CSA has undergone Power Handling test and Multipactor test to validate the high average (500W) & peak power (2KW) handling capability of the unit.