Theory and experiments of plasma antenna radiation emitted through plasma apertures or windows with suppressed back and side lobes

Summary form only given, as follows. The plasma antenna is modeled as a center fed dipole. The net radiated power of the plasma dipole antenna is derived. The surrounding plasma blanket has a variable and controlled density. In the regions of the plasma blanket with the plasma extinguished or with the plasma frequency much less than the antenna frequency, the region becomes transparent to electromagnetic waves from the antenna. In regions where the plasma frequency is much higher than the antenna frequency the plasma behaves like a good reflector and can block radiation. Thus we can create windows or aperture and shape a reconfigurable antenna radiation field. By having the entire plasma blanket have a much greater plasma frequency than the antenna frequency, we can store electromagnetic energy. When we open one or more plasma apertures or windows, we can release the electromagnetic energy as a pulse in reconfigurable radiation patterns. As our first iteration to this calculation, we will assume that an open plasma window surrounded by plasma in the metallic mode is an aperture antenna surrounded by a conductor. In this case we can use equivalence theorems to reduce the problem to equivalent magnetic currents which is essentially the negative of twice the vector cross product of the unit vector normal to the window and the electric field in the plane of the aperture. We will also assume that for a window depth into the plasma blanket at distance much less than a wavelength, the field is constant across the face of the window. In actuality the tangential component of the field at the aperture is the dot product of the unit vector in the z direction and the angular component of the electric field, we will assume that for small windows, the tangential component of the electric field is constant. The second iteration of calculations will take the variation of the field across the aperture into account. We present experimental evidence that plasma apertures or windows suppress the back and side lobes.