合成寬頻平行耦合微帶線帶通濾波器的新公式

Abstract

本文提出一新設計公式，可改進寬頻平行耦合微帶線帶通濾波器之頻寬準確性。當比例頻寬決定時，新的條件Δ= (Δ/2)(1 ±Δ/2) 必須代入每一耦合級之合成公式內。本論文中以新公式設計三階和五階柴比雪夫函數濾波器，通帶漣波為0.1dB，設計頻寬為50%，皆有明顯的改善效果，且模擬和實作之結果相當一致。

New formulas are proposed for designing wideband parallel-coupled microstrip bandpass filters with improved prediction of bandwidth. When a fractional bandwidth Δ is required, a condition Δ= (Δ/2)(1 ±Δ/2) is incorporated into the formulation for determining the dimensions of each coupled stage. Two filters of order 3 and order 5, with Δ=50% are designed and fabricated to show the evident improvement. The measurement shows a very good agreement with simulation.