新穎交錯耦合濾波器之開發設計與寬頻高階馬迅平衡非平衡轉換器合成設計

Abstract

本論文主要的研究方向分成兩大部分，分別為微波濾波器設計與馬迅平衡非平衡轉換器設計。第一部分是研究運用四分之ㄧ波長步階阻抗共振腔設計高性能濾波器、如何快速設計交錯耦合濾波器、以及發展新穎耦合濾波器。文中介紹使用四分之ㄧ波長步階阻抗共振腔來實現具有源級與負載相耦合的四角互耦的濾波器響應，可以任意控制第二對傳輸零點的位置。一般而言絕大部分的設計都是使用耦合係數與外部品質因子來設計濾波器，一旦共振腔型式固定，所萃取的耦合係數只能使用在當時濾波器的中心頻率與當時的實體佈局方式，而且一旦傳輸零點位置改變，共振腔擺放的位置也要改變，重新建立耦合係數與外部品質因子，而且其初始設計離最佳化的廣義柴比雪夫響應相差太多，必須調整濾波器的次數太多，造成難以快速設計。本論文提出以傳統平行耦合線濾波器來達到具有交錯耦合的功能，好處是能夠有最佳的初始設計以及優越的傳輸零點位置的擺放。此外，文中也提出新穎耦合濾波器圖形，此濾波器提供了對稱型的實體佈局實現非對稱的濾波器響應，也克服了傳輸零點非常靠近帶通頻率所造成在平面實體佈局技術的困難度。 論文的第二部份敘述使用傳輸線元件的分佈式電路所組成的網路的合成方法。此合成方法可以預測所有頻率點響應，所使用到的理查變數(Richards variable)、傳輸線網路、理查理論(Richards theorem)、黑田恆等式以及傳輸線近似合成函數都有討論。此外，文中也會提出高階寬頻馬迅平衡非平衡阻抗轉換器的電路，以及如何準確合成具有柴比雪夫響應的馬迅平衡非平衡阻抗轉換器。此種新提出的高階馬迅電路適合寬頻響應。

The research topics in this dissertation are divided into two parts; one is microwave filter design, the other is Marchand Balun design. The first topic is to utilize quarter-wave stepped impedance resonator to design high performance filter, study how to quickly design cross-coupled filters, and develop novel coupling schemes. In this dissertation, quarter-wave stepped impedance resonators are utilized to realize quadruplet and canonical-form coupling schemes. The proposed filter is easy to apply and control the source-load cross coupling. General speaking, most of the filter designs are to use coupling coefficients and external quality factor to design cross-coupled filters. Once the physical layout of the resonator is decided, the extracted coupling coefficients can be only used at the center frequency. Furthermore, if one coupling coefficient in the coupling matrix changes sign for shifting the transmission zero from one side of the passband to the other, the physical layout must be reconfigured. The initial design of cross-coupled filters based on segmentation method is not good enough, so tuning of filter performances must spend much time. This dissertation presents new cross-coupled filters based on a conventional parallel-coupled filter. The proposed filters have the advantages of the ability to locate a transmission zero on the lower or upper stopband and a good initial design. Additionally, the novel coupling schemes are presented to exhibit bisymmetric coupling matrix. The novel coupling schemes provide the implementations of symmetric layouts to realize asymmetric filter responses. Using the novel coupling schemes implementation of generalized Chebyshev filters with transmission zeros very close to the passband can be easily realized in planar technology. The second topic is to describe the synthesis method of the networks which are composed of the distributed transmission line circuits. The synthesis method is exact at all frequencies. Richards variable, transmission line networks, Richards theorem, kuroda identities and transmission line approximating functions are discussed in detailed. In addition, high-order wideband Marchand baluns are presented in this dissertation and the exact synthesis of the proposed Marchand baluns with Chebyshev responses are introduced. The proposed high-order Marchand baluns are suitable to design wideband responses.