Some considerations of an antenna in a high gain configuration

Planar antenna structures may be configured to realize high gain with appropriate layering including a superstrate layer of high permittivity. Such antennas were first understood in terms of transmission line theory optimizing gain using a quarter-wave transformer argument. A prototype of this antenna was constructed and tested validating the high gain effect. Analytical expressions for the electromagnetic fields can be realized using the same methodology commonly used in the analysis of a patch antenna. Calculation of terms in this formulation is consistent with quarter-wave analysis. However, such an analysis presumes an infinite structure on the transverse directions. When an actual antenna is constructed, the planar surface can significantly affect the high gain calculations. The high gain of the antenna must then be reconciled with the fundamental concept of aperture size versus directivity.