| Summary: | 碩士 === 國立臺南大學 === 電機工程學系碩博士班 === 103 === In this thesis, we present a dual-band microstrip bandpass filter, which is constructed by a quad-mode stub-loaded resonator (SLR). Since a multi-mode resonator is able to produce multi-resonance within a single unit, the area saving is significant. The proposed multi-mode resonator is implemented by two stubs allocate at symmetry places. The electric length is correlated to the operated frequency, which it decides the length of the stubs. The even-/odd-mode can be applied to analysis the resonance due to its symmetric structure. Moreover, to suppress the spurious passband, the SIR is applied to shift the harmonic resonance to the higher frequency. Finally, two kinds of dual-band bandpass filter constructed by the quad-mode resonator are proposed, which are designed for WLAN (2.4/5.2GHz). The measured insertion loss and BWR with 1.43 and 14.85% (@ 2.4 GHz), 1.34 dB and 12.95% (@ 5.2 GHz), the reflection loss between two passbands is about −20 dB. By applying two quarter-wavelength stubs, the reflection loss between two passbands gives −40 dB isolation improvement. The measured insertion loss and BWR with 0.82 and 17.37% (@ 2.4 GHz), 1.17 dB and 14.04% (@ 5.2 GHz).respectively.
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