A novel Log periodic implementation of a 700 MHz – 6 GHz slant polarised fixed-beam antenna array for direction finding applications

Recently, Vivaldi antenna elements have been used by Roke to realize direction finding antenna array solutions for full horizon coverage. Unfortunately the Vivaldi elements used previously have certain limitations which make them unsuitable for use in a compact DF (direction finding) antenna array, in particular how the element phase centre position tracks with frequency. This paper describes the development of a wideband DF antenna array, based upon a circular array of eight inward facing slant-polarized Log periodic antenna elements. The array is suitable for both surveillance and DF applications within the 700 MHz to 6 GHz frequency range, and therefore provides the capability to intercept GSM, GPS, 3G, WiFi, WMAX, LTE as well as the primary radar bands. The small size and low weight of the array structure make it suitable for mounting to a UAV, for use on top of a vehicle, or for maritime environments.