| Summary: | 碩士 === 國立彰化師範大學 === 電信工程研究所 === 105 === This thesis proposes microwave circuit designs of balanced and unbalanced duplexing (filtering) antenna, balanced band-pass filter, balanced rat-race coupler, and reduced size wide passband filter using the substrate integrated waveguide cavity (SIWC). The SIWC is composed of the microwave substrate with a via-hole perimeter emulating the cavity’s side walls. Hence, it avoids the waveguide’s bulky mass and high cost, but still preserves the metal waveguide cavity’s advantages, such as low loss, low radiation emission, and high quality factor.
The first chapter presents the integrated design of a SIWC diplexer and the radiating patch antenna. Two patches are employed on the front and back side of the SIWC broad walls for bi-directional radiation. The SIWC diplexer’s broad walls serve as the patches ground plane. The second chapter is devoted to a balanced filtering antenna circuit design. Two vertically stacked SIWCs are used to build a wide-band response balanced filter that is connected to a planar patch forming the balanced filtering antenna circuit. The TE102 and TE201 degenerate modes are excited in the SIWC cavities. The isolation is depended on the orthogonality of the two degenerate modes. The third circuit deals with a 10-dB rat-race coupler using a square SIWC. This circuit has its two input ports in the single-ended form and its output ports are the balanced output port structure.
The size-reduction wideband filter of the SIWC structure is presented in the final of the thesis. To achieve the size reduction performance of the SIWC wideband filter, we use two substrates in a stacked form to build the filter’s resonant cavities with a circular patch deployed in the middle metallic layer and blind via-holes short the patch to the cavity’s bottom. The CPW combined stripline is used to form the filter’s I/O ports with the feeding structure also functions as a resonator. Hence, the shorted circular patch together with the resonant feed create multiple resonances and wide band response is thus resulted.
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