Design And Application Of Filter Based On Spoof Surface Plasmon Polaritions

Surface plasmon polaritons(SPPs)are surface waves propagating along the interface between the metal and the dielectric in the optical frequency region.Spoof SPPs is an important expansion of SPPs in microwave and other low frequency region,which produced by the interaction of elecromagnetic modes in the grooves or holes etched in the metal surface.Spoof SPPs has the similar characteristics with SPPs and overcomes the limitation in the low frequency regions,so it has aroused widespread concern and research.The traditional Spoof SPPs structures are generally complicated for design and manufacture,and they also occupy a large physical space,which make it not conducive to application in microwave circuit system.In this paper,we mainly study the ultrathin planar structure and design the microwave filter based on Spoof SPPs.It can provides a reference for the application of Spoof SPPs in microwave integrated system.The detailed work is as follows:(1)We designed a new type of Spoof SPPs waveguide which is composed of metal strips etched with diamond holes.Due to the existence of the cutoff frequency of Spoof SPPs,the waveguide can be regarded as a low pass filter.The simulation results show that the filter has lower transmission loss and wider bandwidth.(2)We designed a new type of band-rejection filter based on complementary single ring resonators(CSSRRs)and previous waveguide.The simulation results show that when there are 5 CSSRR(radius is 1.8mm)cells etched on the metal strip,the isolation of proposed filter can be less than-20 dB from 10.9GHz to 12.1GHz.The filter can effectively avoid the interference of satellite communication signals in the UWB frequency spectrum.(3)We designed a new type of capacitive-coupled bandpass filter based on the diamond hole structure.The coupling structure was composed with a series metal hole diamond structure units,which arranged in the transmission direction with a certain distance.The simulation results show that the 3dB bandwidth of the filter is from 11.6GHz to 18.3GHz.And the filter exhibits good filtering performance.