| Summary: | 碩士 === 中原大學 === 電機工程研究所 === 98 === This thesis discusses the influence of wave beam synthesis of multi-beam antenna due to phase change. The realistic simulation results tell us that our study gets a significant improvement in practical applications. In our study, we use eight pairs of YAKI antenna to form an antenna array to get eight in-phase signals. It can cause the effect that the gain of the main wave beams synthesis reaches 9dB.
To understand what influence the phase change to the multi-beam synthetic antenna characteristic, firstly, the theoretical analysis of phase change, displacement angle, comparison of antenna patterns between main wave beams and side wave beams, and antenna gain are studied. Secondly, by using the computer auxiliary antenna design software, Personal Computer Aided Antenna Design, (PCAAD), we can calculate the phase of UHF frequencies after the multi-beam antenna synthesis. Then, the antenna field pattern can be obtained to confirm the field intensity, gain, amplitude of side lobe oscillation, and displacement angle of the antenna main wave beam. Finally, the antenna characteristics of multi-beam synthetic antenna with frequency varying due to phase change can be analyzed by our proposal.
This thesis has the following contributions:
1. According to our simulation results, the characteristics of antenna due to phase change can be analyzed to provide the designer to evaluate the actual performance to enhance the antenna's gain.
2. The results of our proposal can provide the following beneficial functions: reduce
the cost of system development effectively, improve the communication quality, and eliminate the multi-path effects.
3. Appling the multi-beam synthetic antenna system to the design of the traditional base station antenna might improve the performance of antenna. Moreover, this application makes the design of traditional base station antenna becomes light, thin, short and small to increases the bandwidth of phase delay.
We believe that the present of this thesis is helpful to the understanding of the influence of antenna characteristic due to phase change, and design of the multi-beam synthetic antenna by this argument. It can remarkably improve the communication quality and effects of elimination of multi-path interference, and will provide a design prototype for the real applications.
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