本文介紹三種射頻印刷電路板被動寬頻帶通濾波器並具有諧波抑制的設計方法，並且都是以三傳輸極點為基礎作設計，最後再將這些方法比較其優缺點。 第一種設計方法先設計一低通濾波器，再並聯三短路殘段至特定節點，此處會因回波損耗太差，所以須將輸出及輸入端的地方加上一段傳輸線作阻抗匹配。第二種方法與上述方法不同之處在柴比雪夫低通濾波器五處節點接上短路殘段，此方法的優點在於不用加上一段傳輸線作阻抗的匹配，所以能夠將原本低通濾波器的截止頻率固定住。 第三種設計為連續耦合之帶通濾波器，藉由給定的傳輸零點位置可直接合成出基礎的集總元件電路，並將此濾波器的集總電路元件由ABCD矩陣求出，並分由三個區塊的架構將集總元件轉為分佈元件。此方法之特點為濾波器的個數N會與傳輸零點的數目相同。 本文第四章用三種設計方法在RO4003C比較，其中兩種方法有實作之結果，印刷電路板之介電係數為3.55、板厚32毫英寸，最後以表格列出效能。 ;In this thesis, three structures of wideband bandpass filter(BPF) are presented and analyzed respectively. Three transmission poles in passband are chosen in the comparison table. The first design differs from transversal approaches that it is based on the choice of a lowpass filter(LPF), to which 3 shunt shorted stubs are added at specific nodes. However, the return loss at this stage is poor and this is corrected by quarter wavelength of the matching elements. The second design is modified by the previously mentioned method, which has the same fundamental LPF; nevertheless, connected with 5 shunt short stubs instead. One of the advantage from the 1st design is that the upper passband edge is fixed because matching elements is not necessary in the procedure. The last structure is a general sequentially coupled wideband BPF. The basic lumped-circuit model can be directly synthesized by given specifications transmission zeros (TZs). Circuit elements can be sequentially extracted from the ABCD matrix. The synthesized lumped element circuit consist of three parts of elementary lumped element circuit that can be approximated by distributed element circuits respectively. Consequently, there are N number of TZs made by the same number resonators in the upper stopband. In the end of this thesis, 3 proposed methods are compared in the discussion. Two of them are implemented on RO4003C with dielectric constant 3.55 and dielectric thickness 32 mil.
