Optimization Study of Radar Cross Section Reduction by an Inhomogeneous Collisional Magnetized Plasma
Recursive convolution FDTD method is employed to study the bistatic radar cross section (RCS) of a conductive plate covered with an inhomogeneous magnetized plasma shroud. The results of numerical simulations reveal that for a plasma of number density 5×1017 m-3 and collision frequency of 1 GHz, RCS reduction (RCSR) is improved i.e., its maximum reduction, bandwidth, and angular width are enhanced, when a perpendicular magnetic field of intensity B=0.25 T is applied. However, increase of the magnetic field to 0.4 T leads to a much lower RCSR specially for the backscattered wave. As the collision frequency is increased to 10 GHz, the RCSR is enhanced both in the presence and absence of the magnetic field. However, with further increase of collision frequency to 60 GHz, the RCSR is significantly reduced and the problem is more severe in the backward direction. The resonant absorption is dominant at low to moderate collision frequencies, for magnetic field intensity above 0.1 T, but becomes almost inefficient when the collision frequency is increased to 60 GHz. The RCSR is considerably weakened when the plasma number density is reduced and the effect is prominent for small angles. A plasma inhomogeneity length scale of 5 cm provides the maximum RCSR in the presence of the magnetic field. With increase of the length scale, the maximum RCSR, the corresponding wave frequency, and bandwidth all are reduced. Therefore, it is conclude that a plasma with number density of 5×1017 m-3, collision frequency of 10 GHz, and length scale of 5 cm, with a perpendicular magnetic field of 0.25 T is the best choice for optimum RCSR of a conductive plate.