Broadband, Low Sidelobe, Zero Height, Slotted Circular Disk Antenna

Abstract

A rigorous mathematical theory for a rotationally symmetrical slotted circular disk antenna was developed. The theory applies the principle of "Gradient Invariance" of electromagnetic fields to determine the field components that are unique and single valued at any point in space.

To detemine the radiation characteristics of the antenna in space, the field at the slot is taken as the secondary source radiation and the solution is carried out in a semi-spherical coordinate system. The expression obtained for the radiation pattern was programmed and the antenna patterns plotted.

The antenna was then constructed and, among others, its radiation patterns plotted.

Such an antenna can have wide ranging practical applications. It is interesting to note that the physical and geometrical constructions of such an antenna allow it to be conveniently mounted on different types of fast flying and/or moving objects without its characteristics being influenced by the strong wind resistances that may exist. In effect, it is a "zero height" antenna with respect to the object on which it is mounted.