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The traditional corner reflector is a type of classical passive jamming equipment but with several shortcomings, such as fixed electromagnetic characteristics and a poor response to radar polarization. In this paper, an eight-quadrant corner reflector equipped with an electronically controlled miniaturized active frequency-selective surface (MAFSS) for X band is proposed to obtain better radar characteristics controllability and polarization adaptability. The scattering characteristics of the new eight-quadrant corner reflector for different switchable scattering states (penetration/reflection), frequency and polarization are simulated and analyzed. Results show that the RCS modulation depth, which is jointly affected by the electromagnetic wave frequency and incident directions, can be maintained above 10 dB in the majority of directions, and even larger than 30 dB at the resonant frequency. Moreover, the RCS adjustable bandwidth can be as wide as 1 GHz in different incident directions. [ABSTRACT FROM AUTHOR]

Hypersonic vehicles are enveloped by a plasma sheath that affects the data transmission and object identification. This paper develops a numerical methodology based on Magnetohydrodynamics equations to study the electromagnetic environment of hypersonic vehicles under the condition of carbon-based thermal protection material ablation. A surface ablation model considering the oxidation and sublimation ablation process is coupled with a Navier–Stokes solver by a gas–solid interaction method to simulate the ablation plasma flows. A piecewise linear current density recursive convolution finite-difference time-domain method is applied to further analyze the interaction between the incident electromagnetic wave and the plasma sheath. The computational results for an HTV-2 type vehicle indicate that both ablation and non-ablation plasma sheaths have significant effects on the electromagnetic environment of the vehicle. Compared with a non-ablation plasma sheath, ablation results in a decrease in the number of electrons and increases the number of neutral particles and therefore changes characteristic parameters of the plasma. Details of the electromagnetic scattering characteristics are reported to highlight the influences of ablation on the reflectivity, penetrability, and absorptivity of the plasma sheath for incident electromagnetic waves over different bands. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]