| Summary: | 博士 === 國立臺灣大學 === 電信工程學研究所 === 102 === Designs of printed antenna fed by coplanar waveguide (CPW) with different backing materials are presented in this dissertation. In the first half of this dissertation, hybrid designs of CPW-fed printed antenna with and without back conductor (BC) are presented. The hybrid designs can adapt themselves to the presence or absence of BC. First, the original hybrid design is proposed, analyzed, and designed. When BC is placed, the antenna is a conductor-backed CPW (CBCPW)-fed side plane patch antenna, while when BC is removed, the antenna becomes a CPW-fed slot dipole antenna. The antenna is designed to have the side plane patch and the slot dipole operate at the same frequency, so that it can adapt itself to the presence or absence of BC. In addition, miniaturization and bandwidth enhancement of the hybrid designs are presented, respectively. Compared with the original design, miniaturized design achieves roughly 40% reduction in size and the overlapping impedance bandwidth of the bandwidth-enhanced design is wider, approximately three times of the original design.
In the second half of this dissertation, design of an electromagnetic bandgap (EBG)-backed CPW-fed slot dipole antenna is presented. The antenna is formed by placing a CPW-fed slot dipole on the top of the EBG structure. It is found that the design considerations of the EBG-backed CPW-fed slot dipole are different from those of the conventional CPW-fed slot dipole. This is because the propagation characteristics of the EBG-backed slotline utilized in the EBG-backed design are quite different from those of the slotline for the conventional design. By using the extracted propagation constant of the EBG-backed slotline, a detailed antenna design procedure is presented.
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