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dc.contributor.advisorJaehoon Choi-
dc.description.abstractThis thesis demonstrates-
dc.description.abstractnovel metamaterial resonant antennas using a single metamaterial unit cell based on the Composite Right/Left-Handed (CRLH) transmission line (TL) approach. The proposed metamaterial unit cell is composed of a complementary split-ring resonator (CSRR) and an interdigital capacitor (IDC). The transmission line approach of the proposed CRLH unit cell reveals unique dispersion property and resonance characteristics. The proposed CRLH TL has a half-wavelength resonance at a much lower frequency than the half-wavelength resonance frequency of a conventional TL. In addition, an extraordinary zeroth order resonance appears in the proposed CRLH TL, which has a zero phase constant and an infinite-wavelength. Moreover it is possible to further decrease the half-wavelength resonance frequency of the CRLH TL by increasing the interdigital finger length without increasing the overall size of the TL. Therefore, a compact half-wavelength resonance antenna using the CRLH structure is proposed. The size reduction of the antenna is achieved thorough examination of the nonlinear dispersion property of the CRLH TL. The proposed antenna has a patch size of 0.173 ┡0 ≠ 0.170 ┡0, 10 dB bandwidth of 1.7%, and a peak gain of 2 dBi. However, the infinite wavelength resonance is not matched to the feed line in this antenna due to the excessively high input impedance of the zeroth order resonance (ZOR). Moreover, the quarter-wave transformer used for impedance matching increases the overall size of the antenna. To resolve these problems, the input impedance at the zeroth and first order resonances are studied. From the study on input impedance of the antenna, the infinite-wavelength resonance is achieved together with the half-wavelength resonance for dual-band operation by using a novel impedance matching method. The proposed dual-band antenna does not require additional matching network-
dc.description.abstracthence the size reduction of the antenna is attained. However, the ZOR has inherent narrow bandwidth �C a major obstacle for the practical use of most of ZOR antennas. Therefore, the ZOR is excluded from the final version of CRLH antenna. Finally, this thesis proposes a wideband CRLH antenna with high gain and near-isotropic radiation pattern. In this antenna, a distinctive method is used to induce the TM01 mode in addition to the conventional TM10 mode. Furthermore, the TM01 mode is combined with the TM10 mode to enlarge the operating bandwidth. The 10dB bandwidth of the proposed antenna is 6.8%, which is six times larger than that of a conventional patch antenna operating at the same frequency band. The mixture of two modes in the same frequency band not only enlarge the bandwidth of the antenna, but also produces near-isotropic radiation patterns for horizontal polarization and dipolar patterns for vertical polarization. Furthermore, the antenna efficiency is as high as that of a conventional patch antenna (over 95%) despite its small size (0.24 ┡0 ≠ 0.24 ┡0 ≠ 0.02 ┡0 at the center frequency).-
dc.titleStudy on Metamaterial Resonant Antennas Based on Transmission Line Approach-
dc.contributor.googleauthorHa, Jae Geun-
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