Design And Application Of A New Type Of Frequency Selective Surface

FSS (Frequency Selective Surface) is an periodic array made up of metal patch or metal aperture, which has total reflection or transmission properties for electromagnetic wave of specific frequency. It is a kind of passive spatial filter. Since the 1960s, the FSS has gradually become the research focus in the field of electromagnetic field and microwave technology. In view of its nice spatial filtering characteristics and low profile to facilitate being conformal, it is usually used in the radome, reflector antenna subreflector, solar absorbing surface, wave polarization device, etc.This thesis focuses on practical application of FSS and the improvement of its performance, the following work and specific research was done:l.The background and significance of the research of FSS are introduced. Analysis of its working principle, characteristic parameters and generation of grating lobes are shown. Three kinds of theoretical methods analyzing mechanism of FSS are listed.2. In this thesis, a new type of band-stop FSS element is designed. The characteristics of different polarization wave of various types of FSS units are also discussed. For the unsatisfying polarization stability of novel band-stop FSS, the array shape is improved. The simulation results the polarization stability has been enhanced after adjusting the arrangement style of the novel bandstop FSS. Then it is put above the traditional microstrip antenna and adjust the distance between the antenna and the FSS cladding to enhance the antenna gain. Through the HFSS software simulation, the results show that the bandwidth of the antenna loaded with FSS cladding is constant, the directivity is enhanced, and the gain in the vertical direction is increased by 8.01dB. According to the design, the microstrip antenna and double-layer FSS are fabricated. After measuring, the results have small differences compared with the simulation data which illustrates the correctness of the design.3.The previous design of bandstop FSS unit has been changed, so that it can be applied in the miniaturization application area. The complementary double-layer structure was designed by changing the structure parameters and utilizing coupling mechanism. Simulation results show that under the premise of the same size at the cell cycle, resonant frequency of the new type FSS units had been decreased by 8.6 GHz compared with traditional Y-shaped units, achieving the purpose of miniaturization. The FSS is applied to the reflecting plate of the printed oscillator antenna. Through software simulation, measurement result shows that this method can reduce the radar cross section (RCS) out of the frequency band of the antenna.