A study on zoning coating method of absorbing materials for stealth aircraft

The application of absorbing materials on military aircraft has greatly improved the aircraft's survivability and operational effectiveness on the battlefield. The coating method of absorbing materials affects the stealth performance of the aircraft. Therefore, a zoning coating method for absorbing materials is proposed in this paper, and it reduces the amount of the absorbing materials and achieves purpose of reducing the aircraft's cost and weight by reducing the coating thickness of the weak scattering source. In this paper, CAD software is used to build a stealth aircraft model. Then through calculating and analyzing the surface current distribution characteristics of the aircraft under different electromagnetic wave irradiation angles, the aircraft's zoning coating design scheme is determined. Later, the electromagnetic scattering characteristics of the aircraft are simulated by the Multi Level Fast Multipole Method (MLFMM) under the circumstance that the electromagnetic wave horizontal illumination azimuth angle is 0-45˚ and the frequency is 3 GHz and 8 GHz. At the same time, the RCS of the aircraft in uncoated and 1.5 mm full coating and zoning coating are obtained. The simulation results indicate that, when the pitch angle is 0˚ and the azimuth angle is within the range of 0-45˚, compared with 1.5 mm-thickness full-fuselage scheme, as for the stealth aircraft after zoning coating design, its RCS average is basically the same as 1.5 mm-thickness full-fuselage coating when the electromagnetic wave frequency is 3 GHZ with 8 GHZ under the circumstance that the amount of absorbing materials reduces by 40 %, and compared with no coating, it reduces by 17dBsm and 22dBsm in the vertical polarization; While compared with no coating, it reduces by 19dBsm and 18dBsm in the horizontal polarization.