| Summary: | 碩士 === 國立勤益技術學院 === 資訊與電能科技研究所 === 93 === This thesis has two parts. Part 1 introduces a global stochastic search optimizer – GA (Genetic Algorithm). The GA is designed for microwave circuits design. Two examples: bridged T type attenuator and branch-line coupler are taken as the testing prototype. The S-parameters of interested frequency range is embedded into the object function so as to achieve an optimal design.
In the Part 2, a RFID (Radio Frequency Identification) tag characteristics tester is designed based on combined coaxial line and circular waveguide structures. The tester is capable to show RFID tag’s resonant frequency and quality factor by the natural resonant phenomena of RFID tag. Moreover, the tester is a simple, closed testing system and has a totally electromagnetic field shielded environment. Any variation of structural parameters of the tester can be accurately controlled under careful calibration. The influence of tester structural parameters on the electrical characteristics of this tester is checked by HFSS (high frequency structure simulator). Based on the theoretical calculations and HFSS’s simulated results, we designed a prototype for 915MHz band RFID. Experiments are preformed by inserting varies on-line RFID tags. These experimental results reveal that the tester can accurately show the resonant frequency of the tags and exactly discriminate good or bad RF tags under tested.
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