Study of the Radar Cross-Section of Turbofan Engine with Biaxial Multirotor Based on Dynamic Scattering Method

With the continuous advancement of rotor dynamic electromagnetic scattering research, the radar cross-section (RCS) of turbofan engines has attracted more and more attention. In order to solve the electromagnetic scattering characteristics of a biaxial multirotor turbofan engine, a dynamic scattering method (DSM) based on dynamic simulation and grid transformation is presented, where the static RCS of the engine and its components is calculated by physical optics and physical theory of diffraction. The results show that the electromagnetic scattering of the engine is periodic when the engine is working stably, while the rotors such as fans and turbines are the main factors affecting the dynamic electromagnetic scattering and the ducts greatly increase the overall RCS level of the engine. The proposed DSM is effective and efficient for studying the dynamic electromagnetic scattering characteristic of the turbofan engine.

Improved FBAM and GO/PO Method for EM Scattering Analyses of Ship Targets in a Marine Environment

The combination of the fact-based asymptotic method (FBAM) and the geometrical optics and physical optics (GO/PO) hybrid method is an effective way to analyze the electromagnetic (EM) scattering from electrically large ship targets in a marine environment because it takes the multiple scattering of the ship targets into consideration as well as the coupling scattering field between the targets and the sea surface. However, regarding an electrically large marine scene that contains a large target, the occlusion judgement process for calculating the multiple scattering field and the coupling field makes it inefficient. To solve this problem, this paper proposes a physical mechanism-based improved method to reduce the invalid occlusion judgment between different patches on the composite ship–ocean scene, and this operation enhances the computational efficiency significantly. With the proposed method, radar cross section (RCS) results of different targets and composite ship–ocean scenes were calculated and compared with the original FBAM and GO/PO method. Numerical results showed that the proposed method had higher efficiency compared with the original method with the same good accuracy. In addition, synthetic aperture radar (SAR) images of a composite ship–ocean scene with different radar parameters and sea conditions were simulated with the proposed method for detection purpose. Finally, the proposed method was used to analyze the EM scattering characteristic of a marine environment with multiple ships.