Fast Rise-time Intensive EMP Protection for Communication RF Front End

An EMP protection circuit for communication RF front end is designed. It works at 300 kHz-200MHz. The design uses multi-stage PIN diode parallel to form low pass filter network. By establishing time domain model, S parameters of protection circuit are extracted, and thereby the matching network is optimized. It realizes response time matching, limit voltage matching, impedance matching, power matching and energy matching. Protection circuit designed accordingly realizes response time less than 1ns and insertion loss less than 0.17. Square wave with 4kV amplitude can be limited to 25V.