In this thesis, we introduce a LHM (Left-Handed Material) with both negative permittivity and permeability. Improvement of gain antenna is achieved by utilizing the characteristics of the LHM which can focus the EM wave.
We start with an analysis of electromagnetic characteristic of LHM, especially its negative index of refraction. Structures with only negative permittivity or negative permeability are also analyzed. Then, we design the structure of LHM that can reduce the sensitivity of S11 of an antenna. So that the antenna operating frequency is not changed even in the presence of the LHM. The LHM unit cell structure comes from the idea by combination of two basic SNG (Single Negative) structure. We design a unit cell whose index of refraction is negative and close to zero. Further, we combine LHM and antenna. Simulation and measurement results show that the LHM is effective. The reflection coefficient of antenna does not change much by the combination of proposed LHM. The half power beam¡Ðwidth of antenna become narrower. The antenna gain improvement can be about 3 dB or higher.
Finally, the LHM has been miniaturized successfully, resulting in reduction in size by about 50%. Comparing simulation and measurement, we find the LHM is still effective. A dipole antenna is used to verify out design. The antenna gain has been enhanced and the reflection coefficient does not change much.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0724108-163206 |
| Date | 24 July 2008 |
| Creators | Lin, Kun-Hsien |
| Contributors | Tzyy-Sheng Horng, Ken-Huang Lin, Chih-Wen Kuo, none, none |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0724108-163206 |
| Rights | not_available, Copyright information available at source archive |
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