Theoretical Research And Design Of Ultra-wideband Frequency Selection Surface

With the development of war technology,the frequency selection surface(FSS)has gradually become a hotspot of research in various countries.This is because FSS has a good choice of electromagnetic waves,and military targets can use this feature to achieve electronic stealth.In response to complex battlefield situations,control systems often use multiple bands to precisely control military targets,so designing FSS w.ith ultra-wideband frequency selection performance is becoming increasingly important.The author analyzes the basic characteristics of the frequency selective surface,and then deeply studies the working principle of FSS,and summarizes the basic rules of controlling the response characteristics of FSS,finally achieves the following innovations:Firstly,according to the coupling principle of multi-layer frequency selection surface,a three-layer ultra-wideband frequency selective surface is designed.The main components are metal patch and metal grid.The simulation proves that the structure has an absolute bandwidth of 16.5 GHz,the relative bandwidth is 101%,and has good angular stability.Then,based on the three-layer structure,the unit structure of the middle layer and the unit structure of the upper and lower layers are combined to obtain a combined unit,and there are two double-layer structure ultra-wideband frequency selective surface is designed accordingly.Their absolute bandw idth is 12.5GHz and 13.6GHz,their relative bandwidth is 56.6%and 58.9%,which fully satisfies ultra-wideband performance.The ultra-wideband frequency selective surface of the two-layer structure effectively simplifies the processing process,makes the engineering realization of the ultra-wideband frequency selective surface simpler and has great engineering significance.In order to enrich the function of FSS,the paper proposes a new design concept,which makes the designed FSS expand a narrowband bandwidth based on the double-layer structure and ultra-wideband performance,achieving dual-band selection.The designed FSS is simulated,in the ultra-wideband bandpass range,the electromagnetic waves incident at different angles have no obvious change in bandwidth,and the loss remains within-3dB,which still maintains good angular stability.For the narrow-band bandpass part,it has a good response in the case of normal incidence,but as the incident angle changes,its response is affected by the grating lobes.These studies provide a new way of thinking for designing multi-band frequency selective surfaces in the future.