Modeling and Analysis of Airborne Conformal Arrays Obstructed by Fixed Blockage

Abstract

An array conformal on an aircraft is affected by fixed blockage on the aircraft. This blockage will cause an increase in the sidelobe level and a distortion of the pattern, which considerably affects target detection. The traditional strategy treats the blockage and antennas as a whole system, leading to increased difficulty in analysis and research on the mechanism of blockage. Thus, this article presents a novel method. On the basis of the Fresnel zone theory of electromagnetic propagation, the main shadow region of electromagnetic propagation of the conformal array by the fixed blockage is found. Then, the shadow region is divided into small scattering elements, which significantly reduces the scope of the solution. Additionally, an association model between the blockage–conformal array system and isolated element is established based on the characteristic modes of isolated elements and coordinate transformation. The proposed method explains the influence mechanism of the blockage on the conformal array from the perspective of the characteristic currents and can accurately describe the influence of the blockage. Finally, several numerical experiments are presented to illustrate the effectiveness of the proposed method.