Study Of High-performance Double-frequency Frequency Selective Surfaces

Frequency selective surfaces (FSSs) as a typical periodic structure, can be thought of as spatial filters for their special filtering properties, and have been widely applied in microwave, infrared, and visible bands. This dissertation focuses on the FSS design by the structure of the left-handed materials. The numerical simulation, the theory analysis and experiment validation of high performance millimeter wave/infrared Ku/Ka dual band FSS have been carried on. The specific researches of this dissertation are listed as following:1. First of all, the FSS basic design theory and methods are given out. The classic Split Ring Resonator (SRR) structure is investigated in the design of dual-band FSS. The numerical simulation and performance analysis are carried out on Split Single-Ring Resonator (SSRR), and in order to eliminate the performance inconsistencies caused by polarization, an improved single ring resonator structure is also proposed. What’s more. Split Double Ring Resonator (SDRR) has also been proposed to design three bands FSS.2. A FSS based on cross dipole loaded with split ring elements with pass-band at8mm MMW band is designed and fabricated. Both simulated and experiment results show that the proposed left-hand materials FSS takes the advantages of stable and good frequency domain response, large bandwidth comparing with traditional FSS, insensitive to the incident angle and polarization. Besides, the reflectivity at IR band reaches more than90%which ensures the reflectivity of the infrared signal.3. A novel dual-band frequency selective surface (FSS) with composite element is presented, in which each periodic cell consists of a square loop loaded with T-shaped stub unit on the front side of the dielectric slab and a capacitive grid on its back side to suppress grating lobes at high frequency. As a result, a dual-band FSS operated over Ku-band (12GHz) and Ka-band (35GHz) is designed. Both simulated and measured results show that the dual-band FSS has good stability to oblique incidence waves and no grating lobe exists between the two pass-bands. What’s more, the novel dual-band frequency selective surface has a larger bandwidth compared with traditional dual band structure.