| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 93 === In Bluetooth and Wireless lan system, their specifications require suppressing not only spurious response but also noise owing to local oscillator. In this study, we focus on characteristics of transmission zeros of microwave passive filters.
In this study, because we need large capacitances to satisfy the specifications of widerbandwidth, and realize those capacitances all in parallel. And by this concept, we design and analyze filters which can suppress noise, one is capacitive coupling and another is magnetic coupling. And, in above two structures, there are transmission zeros which can suppress spurious response, and we have a systematic design flow to explain the phenomenon. At last, we analyze the characteristics of transmission zeros with different
feed point.
By measured results of the capacitive coupling structure is as follow, insertion loss of passband is about -1.5dB and attenuation is about 37dB at 2.1GHz and is larger than 40dB at about 5GHz. And the results of magnetic structure is as follow, insertion loss of passband is about -2.2dB and attenuation is about 40dB at 3GHz and is larger than 60dB at about 5GHz. The results demonstrated that these structures successfully can suppress noise and spurious response.
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