| Summary: | 碩士 === 義守大學 === 電子工程學系 === 101 === The purpose of thesis is to employ the technique of disturbing electric field by dual patches to design microstrip antennas with high design freedom for dual or multi-band operation. The major approach is to use a single disturbing patch to interfere uniform distribution of the electric field into two different modes. Further, various disturbing patch shapes or more numbers of patches is used to increase disturbing, and either to adjust the separation of resonant frequency or to create the function of triple-band operation for microstrip antennas.
For the microstrip antenna with a single disturbing patch, the simulation, experiment and empirical equation confirm that two different modes with acceptable single-beam radiation are produced as expected. As compared with the antenna with rectangular disturbing patch, the separation resonant frequency of the arrowhead shape and triangular shape mentioned in thesis is not only reduced effectively, two modes also offer acceptable single-beam radiation. As the disturbing patches are vertically placed, the electric field distribution from simulation show that there are three different modes produced in cavity, and single-beam radiation still remains.
For the obtained data, this thesis uses the cavity model on the proposed antenna with half cavity and filled substrate to compute the resonant frequency. The data obtained need to modify by using empirical equation. The analysis procedure is easier to understand, and the result shows that the method of empirical equation is useful for resonant frequency estimation. The simulation confirmed by measurement obtains the parameters of antenna with disturbing patch effectively, such as resonant frequency, electric field distribution and radiation pattern.
The various of antennas designed in thesis are all simple with coplanar structure and eligible for PCB manufacture. Moreover, the triple-band antenna can be applied to two commercial bands, so this disturbing patch design is valuable and can offer high design freedom.
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