下載電子全文宣告This thesis is authorized to indicate in-campus access only
You can not download at the moment.
Your IP address is 184.108.40.206
The defense date of the thesis is 2006-04-15
The current date is 2018-06-18
This thesis will be accessible at off-campus not accessible
URN etd-0415106-142811 Statistics This thesis had been viewed 3357 times. Download 223 times. Author Chih-Te Ho Author's Email Address No Public. Department Communication Engineering Year 2005 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 93 Title THICKNESS OF AN AIR LAYER ON THE PERFORMANCE OF A CIRCULARLY POLARIZED REFLECTARRAY USING RING ELEMENTS Keyword Ring REFLECTARRAY CIRCULARLY POLARIZED CIRCULARLY POLARIZED REFLECTARRAY Ring Abstract This thesis studies thickness effect of an air layer on the performance of a reflectarray. The array is composed of ring elements having variable rotation angle. This configuration has been studied in the literature to show its suitability as a high efficiency circularly polarized reflectarray. However, most of the work was made on an expensive substrate. In this thesis, samples were made on a less expensive FR4 substrate. It is show that high efficiency can still be achieved by adding an air layer on the FR4 substrate.
The effect of an air layer is checked by studying the radar cross section incident by a plane wave. It is shown that radar cross section can be tuned by varying the thickness of the air layer and there exists an optimum thickness which can result in the highest gain of the reflectarray.
Experiment has shown that an efficiency of 35.23% can be achieved at x-band. The array was built on a 0.8mm thickness FR4 substrate along with an air layer of 3.0mm. There are 137 elements on an area of 324 cm2. The maximum gain is 25.85dBi. One disadvantage is that the sidelobe level is around 4db. The future study should be focused on reduction of the sidelobe level.
Advisor Committee The-Nan Chang - advisor
none - co-chair
none - co-chair
Files Date of Defense 2006-03-03 Date of Submission 2006-04-15