Design and Analyze of Metal Only Bandpass Frequency Selective Surface Based on Cavities

A metal only bandpass frequency selective surface (FSS) is designed which the unit cell composed of three resonances independent. Bandwidth can be adjusted by combining these resonances. Through introducing three dimension design and high Q value metal cavities, this structure achieve low passband insertion loss and high selectivity. The resonant excitation of two metal cavities and the slot produces three passband poles. The center frequency is 10.0GHz with 1 dB fraction bandwidth of 6.6 %, insertion loss less than 0.5 dB and the attenuation rates larger than 40 dB/GHz. This structure can be made only metal, is easy for manufacture, assembled and low cost.