本論文提出利用交錯耦合形式的多頻帶通濾波器，文中探討兩個多頻微帶線帶通濾波器的結構，包含一個雙頻和一個三頻帶通濾波器。第一部分:雙頻濾波器，我們以兩個耦合開迴路共振器與一均勻阻抗環型共振器(UIRRs)設計新型的交錯耦合結構實現雙頻濾波器。第二部分:三頻帶通濾波器，則是引用步階阻抗共振器的結構在環型諧振腔中，形成週期性步階阻抗環型共振(PSIRR)。我們先分析了三段式步階阻抗共振器的理論，利用步階阻抗特性計算二次諧波與基頻的比值應用在雙頻帶上，可以發現適當設計比值於環形結構內，即能調整混附波響應的頻率位置，再將週期性步階阻抗共振器與耦合開迴路諧振腔交錯耦合，即能形成三頻帶通濾波器。經由量測，設計的雙頻帶、三頻帶濾波器，都與模擬相當吻合。

A multi-band microstrip band-pass filter using cross-coupled structure is presented in this paper. We investigated two kinds of multi-band microstrip band-pass filter structures ,including a dual-band filter and a tri-band filter. For the dual-band filter, we implemented the novel dual-band filters based on coupled open loop resonator and uniform impedance ring resonator with cross-coupled structure. The tri-band band-pass filter was referred to a periodic step impedance resonator structure with ring resonator. By using the theory of tri-section step impedance resonator, we calculated the ratio of fundamental and spurious frequency by SIR for the design of dual-band filters, as well as the correct design ratio for the ring structure. The location of spurious response can be adjusted, which contributed to the tri-band characteristics of the band-pass filter. The measurements were in good agreement with the simulation for the design of dual-band and tri-band filters.

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