Dipole antenna with a composite right and left handed transmission line

An antenna system, or a method of forming such a system, comprises of a dipole element with first and second half elements 1409, 1412 which are fed via respective feed cables passing through a conductive tube 1407 which is electrically connected to a plurality of outer plates 1405 by inner plates 1406 to form a composite right/left handed (CRLH) transmission line. The antenna system may be a wideband collinear antenna array 1401 that comprises linearly stacked dipole structures 1485, 1486, 1487. The inner plates 1406 may provide an inductive connection between the outer plates 1405 and the metal tube 1407. Various additional capacitive and/or inductive formations may be used in the transmission lines. Dipoles and CRLH transmission lines may be arranged radially around a metal tube 1407. The CRLH transmission lines are used to prevent anti-phase currents from being induced in the structure carrying the feed lines.