| Summary: | 碩士 === 國立虎尾科技大學 === 光電與材料科技研究所 === 99 === This thesis presents a design of a bandpass filter with the suppression of spurious modes to improve stopband characteristics. To suppress the spurious modes, the configuration of this proposed bandpass filter adopted the structures of miniaturized hairpin resonator filter, stepped impedance resonators and wiggly-lines.
Both the circuit design and implementation of the proposed bandpass filter were discussed in this study. First of all, we determine specifications of the bandpass filters. And then according to the basic design theory, the structure of filter is obtained with the parameters of the bandpass filters. For simulation, external quality factor, real coupling coefficient and optimum distance of the adjacent designed resonators was computed using Agilent’s ADS design software. Finally, the proposed bandpass filter were fabricated on RO4003C and FR4 substrates with center frequency of 2.48GHz, and by WIN 0.15 μm pHEMT Process with center frequency of 13.5GHz.
In this design, advantages of the proposed bandpass filter are not only a wide stopband or passband, but also a good effect for suppression of spurious resonances and a compact size of the bandpass filter. For implementation of the proposed bandpass filter, the measured responses have close agreement with the simulation responses.
Moreover, inductors and resonators of passive filters produce bigger spurious resistant resulting in a large insertion loss. In order to reduce this insertion loss, we also design a Ku-band active filter to compare with high insertion loss passive filters in this thesis.
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