A Broadband Band-pass Filter Based On Spoof Surface Plasmon Polaritons

Surface plasmon polaritons(SPPs)is an electromagnetic wave propagating along the interface between the metal and the medium,and the spoof surface plasmon polaritons(SSPPs)is an electromagnetic surface that is constrained and propagated on the periodic surface of the metal surface wave,it has a similar dispersion curve with SPPs,has been experimentally proven in recent years can be applied to microwave and terahertz band.Due to the excellent characteristics of SSPPs,in recent years has attracted wide attention from domestic and foreign scholars.Based on this,this paper has carried on the thorough research to the artificial surface plasma structure,has designed the ultra thin broadband band pass filter.First of all,we have analyzed the ultra-thin SSPPs straight waveguide.In this paper,the SSPPs direct waveguide structure is studied deeply from the dispersion relation and the propagation characteristic.The CST simulation results show that the depth of the periodic structure has obvious influence on the cutoff frequency of SSPPs.After processing the finished product to measure,confirmed ultra-thin SSPPs direct waveguide high pass rate.Secondly,based on the SSPPs direct waveguide,we designed the original model based on SSPPs,but because of the transmission coefficient in the 4.8GHz or so has a higher than-10 dB of the protrusions,so the filter should be further improved.Finally,we propose a new type of broadband bandpass filter operating at microwave frequencies based on SSPPs.The proposed filter has excellent performance with low loss,high transmission and wide band.We tested the CST of the broadband filter and processed the test measurements.Both the test and simulation results confirmed that the input loss was about 1.5 dB in the 7 to 10 GHz band.The planar band-pass filter plays an important role in plasma circuits and systems.