Radiation patterns of a slot covered by a simulated plasma sheet

Effect of Thin Plasmas on an Aperture Antenna in an Infinite Conducting Plane

“…If the thickness of the first slab is taken to be such that its electron t ... a R. L Fonte density is much higher than that in the other, it is a fair approximation to retain only the f}rst slab in determining the modification in transmission due to the presence of the plasma. Furthermore, it can be shown (Smith and Golden, 1965) that this layer may be approximated by an impedance sheet if (the conditions given by (l) implicitly assume that the aperture dimensions are of the order of a wavelength. Somewhat more rigorous conditions, derived in Appendix B, require that the condition I VZ I ~ l be supplemented by I VZ I ko ~ 27T/Xo, I VZ I ko ~ 21T/yo, where Xo and Yo are the characteristic dimensions of the aperture) In a great many cases, the inequalities given by (l) are satisfied.…”

“…Wait (1960) has considered the propagation of electromagnetic waves along conducting planes covered by an impedance sheet, and also (1961) the effect of an impedance sheet on the fields of a dipole. Smith and Golden (1965) have made experimental studies on the effect (on radiation pattern) of the distance of an impedance sheet from an aperture in a conducting plane. More recently, Norcross and Meltz (1966) have considered the propagation of surface waves along a conducting plane covered by a dielectric and an impedance sheet.…”