An antenna array assembly, comprising: a ground plate ; a linear array of patch radiator elements (2, 2a-2c) disposed in a spaced parallel relationship with a first face of the ground plate; and a first and second elongate passive radiator each comprising one or more substantially planar conductive parts disposed to be upstanding in relation to the first face of the ground plate and being electrically isolated from the ground plate , the first and second elongate passive radiators being 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; a third and fourth elongate passive radiator each comprising one or more substantially planar conductive parts disposed to be upstanding in relation to the first face of the ground plate and being electrically isolated from the ground plate , the third and fourth elongate passive radiators being disposed symmetrically on either side of the linear array and parallel to the centre line of the linear array, on the same side of the ground plate as the linear array, and further from the linear array than the first and second elongate passive radiators , wherein a width of each of the first and second elongate passive radiators measured in a direction pointing away from the first face of the ground plate is greater than a width of each of the third and fourth elongate passive radiators measured in a direction pointing away from the first face of the ground plate , and characterized in that each of the each of the third and fourth elongate passive radiators is spaced from the first face of the ground plate by a first distance such that each of the third and fourth elongate passive radiators projects further from the ground plate than each of the first and second elongate passive radiators . a ground plate ; a linear array of patch radiator elements (2, 2a-2c) disposed in a spaced parallel relationship with a first face of the ground plate; and a first and second elongate passive radiator each comprising one or more substantially planar conductive parts disposed to be upstanding in relation to the first face of the ground plate and being electrically isolated from the ground plate , the first and second elongate passive radiators being 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; a third and fourth elongate passive radiator each comprising one or more substantially planar conductive parts disposed to be upstanding in relation to the first face of the ground plate and being electrically isolated from the ground plate , the third and fourth elongate passive radiators being disposed symmetrically on either side of the linear array and parallel to the centre line of the linear array, on the same side of the ground plate as the linear array, and further from the linear array than the first and second elongate passive radiators , wherein a width of each of the first and second elongate passive radiators measured in a direction pointing away from the first face of the ground plate is greater than a width of each of the third and fourth elongate passive radiators measured in a direction pointing away from the first face of the ground plate , and characterized in that each of the each of the third and fourth elongate passive radiators is spaced from the first face of the ground plate by a first distance such that each of the third and fourth elongate passive radiators projects further from the ground plate than each of the first and second elongate passive radiators . <EOS>