Research Of Frequency Selective Surfaces With Wide Passband

Nowadays, the frequency selective surfaces (FSSs)as a space filter are widely used, such asan sub-reflectors of in the satellite communication systems in order to realize an antenna with dual feed systems or as a radomes for radar cross section (RCS) control. With the high demand of FSS, the highercentral frequency is required whichconsequently leadsto the higher insertion loss in the passband, and deteriorates the passband performance of the FSS. This research work focuses on the analysis of the basic characteristics of some common FSS structures, including the sensitivity of the incident angles and polarization, the influence of the substrate which used in the FSS, and proposed a few novel FSS structures. The FSS based on the substrate integrated waveguide cavity (SIWC) is introducedin this study and the SIWC-FSS with a center frequency of12.5GHz is investigated for the polarization related and irrelevant FSS.Furthermore, the dual-band FSS with the bandwidth of12.25to12.75GHz and14.0to14.5GHz is also studied.In the hybrid boundary cavity FSS, the single PEC boundary is changed to hybrid PEC and PMC boundary, and two design methods are proposed in this thesis Consequently, two structures of the hybrid boundary cavity FSS are designed and the sensitivity of the incident angles and polarization are analyzed. Furthermore, the structure of the basic hybrid boundary cavity FSS has been enhanced achieving a wide and flatness passband. Finally, these hybrid boundary cavity FSSs, are fabricated and measured in the anechoic chamber, the measured results show a good agreement with the simulation results.The thesis is organized as:Chapter1introduces the background, history and applications of the FSS, Chapter2describes the basic theory and characteristic of the FSS including the Floquet Theory and the grating lobes and surface appearance conditions. We also analyze the basic characteristic of some common FSS structures, including the sensitivity of the incident angles and polarization, the influence of the substrate which used in the FSS. The investigations of substrate integrated waveguide FSS and hybrid boundary cavity FSS are presented in Chapter3、 Chapters4and5, and the summary is drawn in Chapter6.