利用具電阻負載之週期領結結構設計寬頻雷達波吸收材料

Abstract

自二十世紀開始，雷達科技的興起，也使得匿蹤科技逐漸受到重視，在軍事方面是十分重要的，近年來，無論在軍機或是船艦上，皆有匿蹤科技的應用，在雷達系統中都是藉由雷達截面積判斷物體的種類，故許多的研究在探討雷達截面積的縮小以達到讓雷達誤判的目的。目前降低雷達截面積的方式已經有許多種，如改變結構設計、使用吸波塗料以及藉由電磁波的破壞性干涉等，在本論文中，我們使用天線陣列的結構製造出寬頻且有效降低垂直入射方向所造成的雷達面積，最主要是利用天線的特性，在天線操作頻率下能夠有效接收電磁波，當天線接收到雷達發送的電磁波時，能夠有效的接收能量，並且使用與天線輻射阻抗匹配的電阻將所吸收的能量消耗，由於雷達截面積與物體散射能量成正比，當散射能量減少時，在垂直入射方向上的雷達捷面積將有效的降低，且天線若設計良好時，能夠提升操作的頻寬，在本文中會針對此結構參數進行分析，也探討如何設計，最後藉由電磁模擬軟體CST模擬以及實作量測來驗證本結構的效能

From the beginning of 20th century, stealth technology has received great attention for its importance on military radar applications and it has been widely employed on military aircrafts and naval vessels recently. Since evaluation of the target’s radar cross-section (RCS), which is a main subject in stealth technology, provides basic information of the target, researchers have been devoted to RCS reduction to diminish the accuracy of hostile radar system. Approaches such as absorbing coating and Salisbury screen have been proposed and they are feasible to reduce RCS effectively. In this thesis, we present a novel broadband structure for RCS reduction based on the concept of periodic resistive array. Each unit cell consists of a broadband antenna with matched resistive load. Incoming electromagnetic wave from hostile radar is received by the antenna and then dissipated by the resistive load in the operation bandwidth, decreasing the scattered energy of the structure, and broadband RCS reduction is achieved. Specifically, we perform the parametric study of the antenna and the antenna structure is optimized for maximum operation bandwidth. The structure is simulated using commercial EM software CST, and the broadband characteristic is experimentally verified for RCS reduction.