Dualband Reflectarray Using Frequency Selective Surface
Date Issued
2012
Date
2012
Author(s)
Tung, Jen-Jung
Abstract
Two kinds of dual-band(10、12 GHz) reflectarray using two types of slot-type frequency selective surface are presented in this thesis. The first kind of reflectarray is designed for dual-polarization, and the other one is for single-polarization. At first a slot-type unit cell is used to design Frequency Selective Surface(FSS). When the slot-type FSS is resonant(10 GHz), the incident waves with direction of polarization perpendicular to slot could penetrate the FSS, and the incident waves with direction of polarization parallel to slot could totally reflect from the FSS at any frequency. Moreover, adding a parallel slot between the original one would produce a transmission zero(12 GHz) for the direction of the incident waves perpendicular to the slot. Based on the FSS we proposed, two kinds of dual-band reflectarray are presented both with the structure of two-layer dielectric substrate and three-layer metal, dipole/crossdipole reflectarray element on the top layer, FSS unit cell in the middle layer, the ground plane is at the bottom layer. At the passband of FSS(10 GHz), the effective reflectarray thickness of substrate is equal to the thickness of two layers overlaid, and at the total refletion frequency(12 GHz), the effective reflectarray thickness of substrate is only equal to the top layer of substrate. By this way, not only is the bandwidth of two operating frequency almost the same, but it also reduces the coupling effect. We use crossdipole unit cell with single slot-type FSS to design a dual-band dual-polarization reflectarray, and use dipole unit cell with the dual-slot FSS to design a dual-band single polarization reflectarray. The former is implemented and the performance is confirmed by experiment; due to the selection of thickness of substrate is limited, the latter could be only implemented by a compromise one, but still as expected. Finally, a focusing reflectarray is designed for operating at 8-GHz, which is different from the far-field reflectarray design. The focusing reflectarray concentrates the main beam to the point in the near-field region, called focal point. The focusing reflectarray is applied on virus sanitized by microwaves. The virus sample is placed at the focal point and illuminated by microwaves for a while; the experiment and analysis of the activity of virus revealed that the death rate of virus rises up to 93%
Subjects
Frequency selective surface
reflect array
focusing reflectarray
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
index.html
Size
23.27 KB
Format
HTML
Checksum
(MD5):6add8dfa65647b4d248b3d670b181c90