| Summary: | 碩士 === 國立交通大學 === 電信工程研究所 === 105 === In this thesis, we design a planar miniaturized wideband-polarization diversity antenna system (two elements) with asymmetric coplanar strip (ACS) fed structure, used for digital soldiers mobile ad hoc network off-body communication, for solving the problem of connection failed caused by multi-path fading in the application of MANET off-body communication. For reducing the size of diversity antenna, the polarization diversity structure is designed with the asymmetric radiation characteristic of ACS-fed structure to lower the coupling effect between two antenna elements. Different to the ACS-fed diversity antenna in the past studies focused on the miniaturized characteristic of ACS structure and needed to design stubs as isolators on the ground, the proposal antenna could achieve the demand of high isolation, miniaturization design and low cost without isolators. In order to improve the problem of impedance mismatch caused by ACS structure and mutual coupling at low-band frequency, we add a parasitic patch as the coupled matching circuit and change the path of mutual coupling at low-band frequency. The parasitic patch could also enhance the isolation at lower-band frequency. Finally, we measured the diversity effect in the real field, to prove that it could achieve high diversity gain in the real field applications.
The proposed antenna has been fabricated on a FR4 substrate with a single plane for verifying the design concepts, and the overall size of this antenna is 0.178
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