複合式阻抗表面應用於減小雷達截面積之設計

Abstract

在近年來，匿蹤科技相當的熱門，也出現了實際上的應用在軍事方面，如美國的F-22戰機，有許多的研究都在致力於讓物體的雷達截面積縮小，來讓雷達誤判，在本論文中，我們使用所謂的複合式人造磁導體結構來製造出平面且寬頻能有效的在垂直入射方向減少雷達截面積的人造材料，主要原理是應用天線原理中陣列因子的觀念找出兩個人造磁導體，使他們的相位差在一段頻率內在180度附近，於是使得在垂直入射方向的雷達截面積被減少，我們將對此複合式人造磁導體參數做一詳細的分析，我們也將說明如何設計，同時我們也藉由模擬和量測來驗証此複合式人造磁導體結構的效果，最後我們可以得知此方法對於雷達截面積在垂直入射方向的縮小具有良好的功效。

Stealth technology has attracted considerable attentions in military for many years because of the application of radar system in ranging and detection for a moving object such as aircraft and ships. Radar Cross Section (RCS) reduction is an efficient way for stealth by minimizing the reflection of electromagnetic wave towards the incident direction. In this thesis, we investigate the wideband RCS reduction of a planar surface made up of a composite artificial magnetic conductor (AMC). Such a composite AMC consists of two types of unit cell pattern with 180-degree phase shift between them. By interleaving the two patterns and arranging them on a chessboard pattern, for a plane wave normally incident on this surface the reflecting wave will have a null field along the impinging direction. The commercial software based on the finite integration method (CST-Microwave Studio) is used for characterizing the reflection property of the AMC surface and scattering characteristics of the overall structure. Additionally, we have fabricated the structure and measured its scattering response including the bi-static and mono-static. Significantly, a wideband RCS reduction ranging from 16 GHz to 25 GHz is obtained. Since this planar structure can be fabricated using standard printed circuit board technology without via-hole process, it should have potential application in stealth technology.