Novel surface-wave antenna

A circular array of a large number of electrically short vertical dipoles of which only two are driven is described and analysed. The relevant parameters include the length and radius of the identical elements, the distance between adjacent elements and their number. A judicious choice of the parameters can establish one of many possible resonant modes for the current amplitude distribution around generate a horizontally omnidirectional pattern with very high vertical directivity. Applications as a surface-wave generator are discussed. Although the array is not a broadband device, the possibility of operating at several discrete frequencies using the same construction may be an advantage for some applications.