利用多模步階阻抗共振腔設計寬頻及超寬頻帶通濾波器

Abstract

本論文利用步階阻抗諧振腔設計寬頻及超寬頻多模帶通濾波器。依據步階阻抗諧振腔的特性，藉由調整共振腔的結構參數，設計出雙模及三模共振腔，使其共振頻率等於柴比雪夫響應的傳輸極點，同時也對輸入級及輸出級的外載Q做匹配。所製作的四個電路，實作量測結果與模擬結果相當吻合。

Broadband bandpass filters and a ultra-wideband bandpass filter are synthesized based on the multimode property of stepped-impedance resonators (SIRs). Based on the resonance properties of SIRs, the fundamental and higher order resonant frequencies are analyzed against the length ratio of the high-Z and low-Z segments. With proper choice of above parameters, a Chebyshev response for dual- and triple-mode SIR can be obtained. Emphasis is placed not only on designing the input/output (I/O) coupling structures for matching the external Q (Qext) and the circuit bandwidth, but also on matching the resonant peaks of the circuit with the nominal Chebyshev poles. Measured results of experimental circuits show good agreement with simulated responses.