應用互補螺旋矩形共振腔實現微小化帶通濾波器與分工器設計

Abstract

本論文主要為利用互補螺旋矩形共振腔的電路基礎下，提出操作在900MHz與1.5GHz兩個不同頻率的微小化帶通濾波器，最後整合其兩個帶通濾波器形成分工器電路。互補螺旋矩形共振腔為一種後設材料，因其擁有許多獨特的電磁特性且具有縮小化電路的效果，使得在近年來被廣泛的應用在微波電路與天線上。 論文前半部分介紹帶通濾波器的基本架構，其主要是由互補螺旋矩形共振腔搭配耦合指叉電容來達成帶通濾波器的低頻區選擇性與帶通範圍。再利用串聯LC共振腔來製造傳輸零點，然後整合帶通濾波器與串聯LC共振腔來改善高頻區選擇性，最後則利用等效電路的觀念，來解釋帶通濾波器的各個部份。 論文後半部分則是整合兩帶通濾波器形成微小化分工器，透過前端的匹配電路，使分工器能達到在微小化的條件之下，仍擁有優良的效能。本研究提出之新型分工器無論在隔離度、訊號抑制能力、電路尺寸的表現都比一般傳統的分工器還要突出。此後設材料概念提供了一些方法來解決一般在微波電路設計時，常會遇到電路面積與效能之取捨問題，並增加與其他電路或天線之整合性。

In this thesis, we propose the design of miniaturized bandpass filters (BPFs) using complementary spiral-rectangle resonators (CSR), which are operated at two different frequency 900MHz and 1.5GHz, respectively. Finally, we integrate two BPFs into diplexer circuit. The complementary spiral-rectangle resonator, which is one kind of the metamaterials exhibits unique electromagnetic properties and the effect of miniaturized circuits that lead to a wide range of application in microwave circuit and antenna design. In the first part of this thesis, we will introduce the fundamental structure of the BPF. The BPF is implemented by utilizing CSR and coupled interdigital-capacitor to accomplish low frequency region selectivity and bandpass range. The series LC resonator are used to produce transmission zero to improve the high frequency region selectivity. Finally, we proposed the equivalent circuit concept to explain the various parts of the BPF. In the last part of this thesis, we use the matching circuits to integrate two BPFs into miniaturized diplexer design. Not only does the diplexer achieve under condition in miniaturization, but has excellent performance. In the research, the isolation, signal suppression, and circuit size of the novel diplexer are more excellent than conventional diplexer. Moreover, the metamaterials concept offer some methods to solve the trade-off in microwave circuit design, and increase the integration with other microwave circuit or antenna.