wide band antenna

An antenna comprising an array 100 of antenna elements 102 where each antenna element 102 comprises an elongate portion substantially located within a plane and comprising a pair of tapering antenna blades defining between their facing edges a notch and wherein antenna elements in a first plane are separated from antenna elements in an adjacent plane by a distance less than or equal to half of the wavelength of the upper operational frequency of the antenna. The antenna may provide a spatially over-sampled wide-band antenna array. The distance between the said antenna planes may be less than or equal to a quarter of a wavelength of the said upper frequency. The antenna array may include plural driven and passive elements. The driven elements may be located generally in the centre of the array. The aspect ratio of the distance from the feed point to the end of the notch and the distance between the outer edges of the blades may be at least 3 to 17, or more. The distance between the feed point and a notch end may be between 2 and 3 metres. The antenna may use Vivaldi antenna elements with metal or conductive or dielectric planar sheets 101 between and/or around the antenna elements 102.