共轴旋翼高速直升机雷达散射截面计算及雷达吸波材料影响分析

为准确高效地预估共轴旋翼高速直升机的雷达散射特性,结合雷达吸波材料(Radar absorbing material,RAM)在隐身设计中的应用,开展了共轴旋翼高速直升机雷达散射截面(Radar cross section,RCS)特性及涂覆型RAM对其影响的研究。首先,基于计算涂覆目标表面散射的物理光学法(Physical optics,PO)和计算涂覆边缘绕射的等效电磁流法(Method of equivalent current,MEC),建立了计算RCS的高频方法,并通过涂覆了RAM的金属球和直升机矩形桨叶算例验证了其有效性。在此基础上,研究双旋翼、尾部螺旋桨、平垂尾和机身在鼻锥、侧向和尾追3个典型方位的雷达散射特性和强散射源分布,并采用局部涂覆RAM的方法进行隐身设计。研究表明:尾部螺旋桨、共轴旋翼桨毂及其整流罩部位、机身上曲率较大的鼻锥和尾部以及曲率较小的侧面护板是机身的重要强散射部位。在强散射部位涂覆RAM能有效降低高速直升机各方位双站RCS的均峰值,显著提升高速直升机隐身性能的效果。

Radar cross section calculation on coaxial rotor high speed helicopter and effect analyses of radar absorbing material

In order to accurately and efficiently estimate the radar scattering characteristics of coaxial rotor high speed helicopters, the radar cross section (RCS) characteristics of coaxial rotor high speed helicopters and the influence of coated radar absorbing materials (RAM) on them are studied according to the application of RAM in stealth design. Firstly, the high frequency method for calculating RCS is established based on the physical optical (PO) method for calculating the coating surface scattering of the target and the method of equivalent current (MEC) for calculating the coating edge diffraction. The effectiveness of the high frequency method is proved by the calculation of the metal ball and the rectangular paddle of the helicopter coated with RAM. The radar scattering characteristics and the strong scattering source distribution of the two polar azimuths and the fuselage in the nasal cones, lateral and tail trapping are studied, and the method of locally coating RAM is used to stealth design. The study shows that the coaxial rotor hub and its fairing parts, the larger curvature of the nose and tail and the smaller curvature of the side fence are important strong scattering parts of the body. Strong scattering parts coated with RAM can effectively reduce the high speed helicopter RCS in all the direction, and significantly improve its stealth performance.