| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 102 === In 2001, the FCC (Federal Communications Commission, USA) allocated a bandwidth of 7 GHz in the range from 57 to 64 GHz. Because the spectrum is unlicensed, it is receiving more and more attention. For this communication, the availability of several GHz bandwidths can be realized in multi-Gbps which can be 40–100 times faster than current WLAN (Wireless Local Area Network) technologies. This spectrum used for short-range wireless applications has high signal attenuation caused by the absorption of oxygen molecules as operating frequency rises to 60 GHz. This disadvantage can be compensated for by using high-gain directive antennas.
To overcome the problem mentioned above, we aimed to design a high-gain antenna. For the requirement of high gain, we use the concept of superstrate, effective radiated area, and transmission line model to enhance the performance of gain. We also design a high gain superstrate antenna successfully. Then, a zero-index MTM based unit-cell operating at 60 GHz has been designed for gain enhancement of Yagi antenna.
In this thesis, we design high-gain directive antenna successfully. The proposed superstrate antenna possesses broadside radiation, maximum gain of 15 dBi, and flat gain response within 57-66 GHz. The proposed zero-index metamaterial antenna loaded with three layers of MTM directors can enhance the gain by about 4.6 dB which achieves a maximum gain of 10.44 dBi.
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