The Integrated Design of RF Front-end Filter and Limiter

Nowadays, the advancement of strong electromagnetic weaponry is becoming increasingly sophisticated, leading to a growing interest in electromagnetic protection technology. In the front end of RF circuits, it is crucial to select an appropriate input signal through frequency selection and amplitude limiting processes to ensure the normal functioning of subsequent circuits. Typically, a filter and a limiter are utilized for achieving these objectives. This paper proposes an integrated design of limiter and filter based on a comb filter design scheme.The simulation results show that in the range of 7GHz-8GHz, the band-pass filtering characteristic under small signal is realized, the insertion loss is less than 2dB, the shielding characteristic under high power is realized, and the shielding efficiency in the passband is greater than 13dB. The nonlinear curve demonstrates that with the increase of input power, the change of shielding efficiency increases slowly and then rapidly, which ensures the communication quality, improves the burn-resistant capability of the filter, and protects the normal operation of the subsequent circuit.