Novel Designs of Frequency Selective Surfaces in EMI Shielding, Dual Bands, and Reconfigurable Structures
Date Issued
2015
Date
2015
Author(s)
Huang, Fan-Cheng
Abstract
Three topics of frequency selective surfaces (FSSs) are discussed in this dissertation: circular-ring miniaturized element (CRME) metasurfaces, very closely located dual-band FSSs and mechanically reconfigurable FSSs. CRME FSSs/metasurfaces are a new type of miniaturized FSSs with circular shapes in unit cells. They not only perform good miniaturization which is useful in applications with limited space but also show other good features such as stable frequency responses to different incident angles and polarizations at the same time. Very closely located dual-band FSSs present a design to shrink the ratio of two operating bands to be as small as 1.06. Also, an approach to fine tune the band ratio from 1.06 to 1.10 is proposed with the first band nearly fixed. These features enhance the usage of bandwidth of multi-band design, because the demands for communication bandwidth are increasing. Mechanically reconfigurable FSSs provide a method to change the operating frequency of FSSs by using a stretchable substrate. It is a passive and easy to implement approach in reconfigurable designs, making the FSS panel suitable for different bands. The periodicity of unit cells is changed by stretching the stretchable substrate. As a result, the coupling between unit cell elements is changed, so as the operating frequency. The full-wave solver, HFSS (finite element method), is applied to design the unit cell element of FSSs and examine performances of FSSs. Frequency responses with S parameters are investigated with respect to different incident angles and polarizations. Furthermore, the prototypes of the designed FSS are fabricated and tested in an anechoic chamber in order to verify the performances of FSSs.
Subjects
Frequency selective surfaces
Metasurfaces
Spatial filters
Bandpass filters
Miniaturization
Electromagnetic interference
Electromagnetic shielding
Dual band
Bandstop filters
Periodic structures
Reconfigurable FSSs
Type
thesis