平面式準指叉型交錯互耦濾波器

Abstract

本研究計畫運用平面式之電路結構及介電系數較低的材料，且採用較為簡單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6GHz的頻段(Hyper LAN 5.3GHz and WLAN 5.7GHz)。 文中將介紹有廣義柴氏響應(generalized Chebyshev function response)特性之三階電性以及四階交錯互耦帶通濾波器(cross-coupled bandpass filters)，並實際製作雛形電路驗證設計流程的可行性及可靠性，最後比較其不同於一般柴氏濾波器而在有限頻率上引入傳輸零點，使得止帶之高或低頻側邊有較強之頻率選擇性，證明了它們的優異性。

In this report, miniature bandpass filters with planar structure and low dielectric constant subtrate are constructed by using a simple and time-saving method. This kind of filters are suitable for the usage in Hyper LAN 5.3GHz and WLAN 5.7GHz. A trisection and a coupled quadruplet bandpass filters, exhibiting electric or magnetic cross coupling, with generalized Chebyshev function response are introduced. Furthermore, design procedures and equations of both types of filters are developed. Two filter designs of this type are described to verify the accuracy and reliability of synthesis theory. The filters are seen to have very steep skirt because of allowing an attenuation pole of finite frequency on either the high side or the low side of the stopband.