並排微帶線的遠場輻射快速預測方法

Abstract

本論文針對印刷電路板上的微帶線產生電磁輻射做數值化分析。首先對於單一微帶線，我們利用傳輸線理論及遠場Green’s function推導出遠場電場的closed-form solution，接著考慮天線理論中陣列因子的概念，將問題延伸到並排微帶線。如此一來，只要知道印刷電路板的材質、微帶線的尺寸及電路源與負載端的阻抗，就可以快速計算不同頻率時，空間上半平面各處的遠場電場。差模與共模輻射理論模式的準確性則由HFSS模擬軟體加以證實。

An analytical study of the unintentional electromagnetic radiation of the parallel microstrip signal traces is presented. Based on transmission-line theory and far-field Green’s function, a closed-form solution for electric field radiated by a single microstrip line is developed. When the structure changes to parallel microstrip lines, we apply the concept of array factor in antenna theory to solve this problem. It allows calculating frequency and angular response of far-field radiation emission of upper half plane, depending on the PCB’s material and dimension parameters and termination load impedance. The differential- and common-mode radiated emission models are validated by the commercial full-wave simulation package HFSS.