Flush mounted tacan base station antenna apparatus

摘要

A flush-mounted radiating antenna is disclosed which can be electronically switched to produce a rotating directional field with no moving parts in the antenna element itself or with the appropriate electronics in the entire mechanism. This is accomplished by utilizing pie-shaped sections on the flush surface which are capacitively coupled to a central feed element and shorting some of the pie-shaped capacitively coupled elements to a ground plane whereby the normally omnidirectional pattern is perturbed to a directional pattern.