Antenna element and array antenna

Abstract

An antenna element for an array antenna comprises a transmission line (1) passed through a ground plane (3), connected at an excitation point (8) to a flat, conductive, helical excitation element (6) mounted on a dielectric substrate (4) on the top of and parallel to the ground plane (3). The distance between the excitation element (6) and the ground plane (3) is greater than one eight of the longest wavelength of the signals with which the antenna is arranged to operate, and preferably between 0.25 and 0.50 times the wavelength. The path length of the electric conductor that constitutes the excitation element is greater than the said wavelength, and preferably between 10 and 100 times the wavelength. This causes the excitation element to operate as a leakage wave structure, with the result that the antenna element becomes non-resonant. An array antenna is further described with a number of such antenna elements arranged in a square matrix configuration, where a common ground plane (3) and a common substrate (4) are employed. A dielectric lens (7) is mounted on the top of the antenna element or the array antenna.

Dependencies are inferred from the claim text.