Abstract: An antenna element comprises a planar conductive reflector plate, a first planar substrate carrying a ground plane having a slot and a feed track crossing in the slot, a plurality of further planar substrates, each carrying a respective radiator patch having a shape that has the same proportions as each other radiator patch and a width which is different from each other radiator patch, and a planar non-conductive cover. The planar conductive reflector plate, the first planar substrate, the plurality of further planar substrates, and the planar non-conductive cover are disposed as successive parallel layers. The separation between successive radiator patches is less than 0.1 wavelengths at an operating frequency of the antenna element and a separation between the radiator patch closest to the planar non-conductive cover and the planar non-conductive cover is less than 0.25 wavelengths at an operating frequency of the antenna element.

Abstract: A Cassegrain antenna comprises a primary reflector dish, a sub-reflector and a first waveguide antenna element disposed as a feed for the sub-reflector. The first waveguide antenna element comprises a waveguide body having a conductive back plate electrically connected to the waveguide body, a first radiator patch, a second radiator patch, and a first planar substrate carrying a ground plane. The first radiator patch, the second radiator patch and the first planar substrate are disposed within the waveguide body and substantially parallel to the conductive back plate. The ground plane comprises a slot on a first side, the first side being disposed towards the second radiator patch, and the first planar substrate carries a feed track corresponding to the slot on an opposite side of the first planar substrate to the side carrying the ground plane.

Abstract: An antenna array assembly comprises a ground plate, a linear array of patch radiator elements disposed in a spaced parallel relationship with a first face of the ground plate and a first and second elongate passive radiator each comprising a plurality of conductive parts electrically isolated from the ground plate. The first and second elongate passive radiators are disposed symmetrically on either side of the linear array and parallel to a centre line of the linear array, on the same side of the ground plate as the linear array. At least some of the conductive parts of a respective elongate passive radiator are disposed in an arrangement having parallel ridges and grooves, in which, in a cross section in a plane parallel to the first face of the ground plate, the ridges extend towards the linear array and the grooves extend away from the linear array.

Abstract: An antenna array assembly comprises a ground plate, a linear array of patch radiator elements disposed in a spaced parallel relationship with a first face of the ground plate, and a first, second, third and fourth elongate passive radiator, each comprising one or more substantially planar conductive parts which are electrically isolated from the ground plate. The first and second elongate passive radiators are disposed symmetrically on either side of the linear array and parallel to a centre line of the linear array, on the same side of the ground plate as the linear array. The third and fourth elongate passive radiators are disposed further from the linear array than are the first and second elongate passive radiators. Each of the third and fourth elongate passive radiators is narrower than and projects further from the ground plate than does each of the first and second elongate passive radiators.

Abstract: An antenna array assembly comprises a ground plate, a linear array of patch radiator elements disposed in a spaced parallel relationship with a first face of the ground plate, and a first, second, third and fourth elongate passive radiator, each comprising one or more substantially planar conductive parts which are electrically isolated from the ground plate. The first and second elongate passive radiators are disposed symmetrically on either side of the linear array and parallel to a centre line of the linear array, on the same side of the ground plate as the linear array. The third and fourth elongate passive radiators are disposed further from the linear array than are the first and second elongate passive radiators. Each of the third and fourth elongate passive radiators is narrower than and projects further from the ground plate than does each of the first and second elongate passive radiators.

Abstract: An antenna array assembly comprises a ground plate, a linear array of patch radiator elements disposed in a spaced parallel relationship with a first face of the ground plate and a first and second elongate passive radiator each comprising a plurality of conductive parts electrically isolated from the ground plate. The first and second elongate passive radiators are disposed symmetrically on either side of the linear array and parallel to a centre line of the linear array, on the same side of the ground plate as the linear array. At least some of the conductive parts of a respective elongate passive radiator are disposed in an arrangement having parallel ridges and grooves, in which, in a cross section in a plane parallel to the first face of the ground plate, the ridges extend towards the linear array and the grooves extend away from the linear array.