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A multilayer radar-absorbing structure with plasma- and radar-absorbing material (RAM) is established to investigate the stealth mechanisms of the multilayer absorber. The method of impedance transformation with multiple dielectrics is used to analyze the propagation of electromagnetic (EM) waves in the multilayer structure. The dependences of EM waves attenuation on the parameters of the plasma and RAMs are provided. The numerical results indicate that generally speaking, the joint attention effect of RAM and plasma is better than the effect of either RAM or plasma solely. The attenuation of an EM wave in the structure is strongly affected by: a) the characteristics of RAMs; b) the width of the plasma layer; c) the parameters of the outer layer material; d) the electron density of the plasma; and e) the collision frequency between electrons and neutrals. It is demonstrated that detailed numerical analyses are useful in practical applications pertaining to the control of the reflection of EM waves through a multilayer radar-absorbing structure with plasma and RAMs. [ABSTRACT FROM PUBLISHER]

Terahertz (THz) waves have been attracting much attention for a variety of technologies in recent years. However, only limited several experimental investigations on the terahertz characterization of plasmas have been reported. In this paper, a finite-difference time-domain method is applied to model the terahertz wave propagation in a high-temperature unmagnetized plasma. The rational polynomial function is established based on a hot plasma dispersion relation, and then, the relationship between D and E is deduced in the time domain. In the frequency domain, the reflection and transmission coefficients of terahertz waves through the hot unmagnetized plasma slab are computed, and their dependences on plasma frequency, plasma thickness, and collision frequency are studied. The results show theoretically that, when the terahertz wave passes through the plasma layer, its amplitude is obviously modulated by the electron density profile, the collision frequency, and the electron temperature. Finally, the potential application of terahertz waves in plasma diagnostics has been discussed. [ABSTRACT FROM PUBLISHER]