微型化雙層帶通濾波器設計

Abstract

本論文闡述如何運用層數較少的電路結構及介電係數較低的材料，且採用較為簡單而不費時的設計方法製作微型化帶通濾波器，使其能適用於無線通訊5至6 GHz的頻段( Hyper LAN 5.3GHz and WLAN 5.7GHz)。 我們將介紹平行耦合式及梳形耦合式兩種微型化帶通濾波器，並且針對特性較為敏感的梳形耦合微帶線提出補償的方法，使其良率 (yield) 得以提昇。另外我們也介紹交錯耦合帶通濾波器(cross-coupled bandpass filters)，它也有微型化的作用，文中將概要性地介紹引入電容性及電感性交錯耦合之髮夾形 (hairpin) 帶通濾波器。以上除理論的推導外，最後製作雛型電路以驗證理論的正確性。

In this thesis, we describe a two layered bandpass filter. It is suitable to reduce size even using low dielectric constant substrate. A simple, non-time-wasting design procedures is also developed. The miniaturized filter can be used in 5-6GHz band in wireless communication, such as Hyper LAN 5.3 GHz and WLAN 5.7 GHz. Two types of miniaturized bandpass filters, namely, parallel edge coupled and comb type coupled bandpass filter, are developed. When comb type coupler is realized in microstrip circuit form, the unequal even- and odd-mode velocity degrades the filter performance seriously. By using analytical equivalent circuit model, this problem is solved. The yield can be improved by using this new design procedure. The cross-coupled filters can miniaturize the conventional bandpass filters, too. Hairpin-resonator bandpass filters with electric and magnetic cross coupling are introduced. Design procedures and equations for all types of filters are developed. An example for each type of filters are designed and fabricated to verify the accuracy of synthesis theory.