| Summary: | 碩士 === 國立暨南國際大學 === 電機工程學系 === 105 === The rapid development for wireless communication is occurring in recent years. There is also a growing demand for wireless local area networks (WLAN). Therefore, the main purpose of this thesis is to study and can be applied to wireless communication of the novel wideband bandpass filter. It has the effect of magnetic coupling by the addition of via; the resonator’s gap also creates the form of electrical coupling by each other. The two coupling forms together constitute the overall architecture of the filter. Simultaneously, adding the stub-loaded line to suppress outside the passband of the high frequency transmission zero, suppressing at 25 dB below to achieve good characteristics of spurious frequency with high isolation effect.
In this study, the wideband bandpass filter is able to apply for 2.45 GHz WLAN band. The overall size is 16.5 mm × 8.17 mm, which is equivalent to 0.11 × 0.05 . It can be seen that the structure size is very small, and has both broad band and the characteristics of transmission zeros. When designing the filter, the analysis tool is full-wave electromagnetic simulation software for IE3D and HFSS, and measured is Agilent N5230A PNA-L vector network analyzer.
The center frequency of design is 2.45 GHz with 858 MHz bandwidths, 3-dB fractional bandwidth ratio of 35 %, and insertion loss of 0.85 dB. There are three transmission zero features outside the passband, which are close to the passband of 1.65 GHz, 3.29 GHz and high frequency transmission zero 4.9 GHz with a certain degree of isolation. This thesis has both wideband and compact size advantages with high frequency selectivity. It can be adopted to people's demand band.
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