Studies of the Focal Region of a Spherical Reflector: Geometric Optics

In addition to the five-term method, mainly for the reason of comparison, a conventional numerical method is also used. The two methods are compared to the experimental data and to each other in the special case of nonstaggered array. The agreement is quite good. In the case of two antennas in collinear and in echelon, no experimental data are yet available. The two theoretical methods are, however, in good agreement. It is found that the antisymmetric current is quite important in full-wave antennas, especially when the antennas are close together. The antisymmetric current however is small in the half-wave antennas. The mutual coupling effect is found to be largest for nonstaggered antennas and smallest in the collinear array. Since the theoretical currents are expressed in terms of simple trigonometric functions, the method can be easily extended to two- or three-dimensional parallel antenna arrays. This application will be described in a subsequent paper.