Self-Switchable Broadband Waveguide Protector Against High Power Microwave

A self-switchable broadband waveguide protector against high power microwave (HPM) is proposed in this letter, which can react to the power intensity of an incident wave adaptively. The protector is composed of three metal layers with multiresonance characteristic and four PIN diodes are loaded. It can realize self-switchable HPM protection in a wide frequency range. An equivalent circuit is carried out to interpret the working mechanism of the protector. Then, a prototype in WR90 waveguide is designed and simulated. The results of simulation show that low power signal can propagate through the protector with insertion loss less than 0.5 dB in the whole working band of the waveguide. Once the power of the incident signal exceeds the protection threshold of the protector, signal can be attenuated by more than 12.8 dB. To verify the accuracy of the design, a waveguide measurement is conducted under different input power levels and the results of measurement have demonstrated the self-switchable HPM protection performance of the protector from 8.2 to 12.5 GHz. The proposed protector can be applied to HPM protection for broadband systems with the waveguide.