| Summary: | 碩士 === 國防大學中正理工學院 === 電子工程研究所 === 96 === This thesis proposes three antenna designs of printed aperture antennas with ultra-wideband (UWB) operations. The first design of UWB aperture antenna is constructed by a hat-shaped patch on the back side of a square aperture. By properly adjusting the length, width and the notch size of the back patch and choosing the gap between the bottom sides of the back patch and the aperture, the VSWR value within different frequency range can be lowered. Furthermore, for avoiding the interference between the UWB and WLAN systems, a pair of inverted-U-shaped slit was embedded in the hat-shaped back patch. The second UWB antenna design is also constructed by a square aperture and a CPW feed-line with a widened protruding signal strip into the aperture. By tuning unequally widened widths toward two sides of the protruding signal strip, good impedance match within the lower band or higher band can be obtained, respectively. As for the third designed antenna, UWB performance is achieved by three rectangular patches extended from the protruding signal strip of the CPW feed-line of a rectangular aperture antenna. The band-rejection characteristics of the UWB rectangular aperture antenna can be obtained by embedding a grounded patch into the aperture. These UWB antenna designs not only have a small antenna size, simple shapes of radiator, ground plane and feeding structure, but also achieve UWB performances by using easily tuning techniques.
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