Wideband And Large Incident Angle Wave Transparent Material Based On Frequency Selective Surface With Miniaturized Elements

Nowadays, the frequency selective surface (FSSs) as a space filter are widely used, such as an sub-reflectors of in the satellite communication system in order to realize an antenna with dual feed systems or as a radomes for radar cross section (RCS) control. With the development of frequency selective surface, its application in engineering is more and more widely, in order to adapt to various applications and frequency requirements, frequency selective surfaces composed of people wave-transmissivity properties of materials are increasingly high requirements, such as large incident angle, broadband and polarization insensitive characteristics.In view of this, this paper mainly do the following work:1. We introduce the research background and basic properties of frequency selective surface, progress of modern research and its widely used in national defense in.2. We introduce the basic working principle of frequency selective surface, emphatically introduces the method of equivalent circuit of this design and analysis method of frequency selective surface. The basic structural unit of frequency response characteristics of the surface are then analyzed using this method.3. Starting from the traditional frequency selective surface, the unit structure for the capacitive FSS and metal grid inductance type FSS metal patches become constructing the smallest unit of frequency selective surface (mFSS). Focus on the application of mFSS in wave transparent materials (WTM), we designed a band-pass WTM with unit cell of air gap and metal, analyzed their intrinsic capacitance and inductance, and explored the parameters of mFSS unit and equivalent circuit on the performancesof WTM. A bandpass WTM sample working at10GHz was designed and fabricated. The measurements demonstrated that the sample was wideband, insensitivity to the incident angle and polarization; the-1dB bandwidth over40%at normal incidence and up to20%even at large incident angles60°. The experiment results are in good agreements with the calculations. The advantages of mFSS based WTM expand its applications for the waves with arbitrary wave front, especially on the radomes.3. In the above miniaturized unit with single frequency selective surface (mFSS) to achieve large incident angle broadband wave transparent materials based on cascaded to filter, the circuit design method for the theoretical basis, construct the wave transparent material double minimum structure element frequency selective surface composition, the electromagnetic wave propagation simulation and the experimental demonstration, analysis of the wave transparent material has more broadband wave transparent properties of this transmission characteristics, and by changing the frequency selective surface structure element spacing and filling material, the wave transparent materials passband bandwidth and the relation with the internal loss changes with these parameters, the rationality of multilayer minimum element frequency selective the surface structure of wide passband through this design method of wave absorbing materials from two aspects of theory and engineering application.