An antenna system for a satellite communications device, the antenna system comprising: a smart aperture electronically steerable antenna comprising a plurality of radiating elements, wherein the radiating elements are selectively activated; and a smart aperture antenna controller unit configured to: obtain a scan angle (θ) and a skew angle (Φ) relative to a communications satellite; determine an antenna activation pattern including the radiating elements that are selectively activated to form an active aperture, wherein the antenna activation pattern is based at least on the scan angle (θ) and the skew angle (Φ); and control the smart aperture electronically steerable antenna according to the antenna activation pattern; characterized in that the radiating elements are arranged along an inner nominal region and an extended region, outer to the inner nominal region, of the smart aperture electronically steerable antenna; and wherein to determine the antenna activation pattern the smart aperture antenna controller unit is configured to: select a mode of operation from at least: a nominal aperture mode of operation, in which only a plurality of radiating elements of the inner nominal region are selectively activated; and an extended aperture mode of operation, in which a plurality of radiating elements of both the inner nominal region and the extended region are selectively activated; and determine the antenna activation pattern for the selected mode of operation. a smart aperture electronically steerable antenna comprising a plurality of radiating elements, wherein the radiating elements are selectively activated; and a smart aperture antenna controller unit configured to: obtain a scan angle (θ) and a skew angle (Φ) relative to a communications satellite; determine an antenna activation pattern including the radiating elements that are selectively activated to form an active aperture, wherein the antenna activation pattern is based at least on the scan angle (θ) and the skew angle (Φ); and control the smart aperture electronically steerable antenna according to the antenna activation pattern; obtain a scan angle (θ) and a skew angle (Φ) relative to a communications satellite; determine an antenna activation pattern including the radiating elements that are selectively activated to form an active aperture, wherein the antenna activation pattern is based at least on the scan angle (θ) and the skew angle (Φ); and control the smart aperture electronically steerable antenna according to the antenna activation pattern; characterized in that the radiating elements are arranged along an inner nominal region and an extended region, outer to the inner nominal region, of the smart aperture electronically steerable antenna; and wherein to determine the antenna activation pattern the smart aperture antenna controller unit is configured to: select a mode of operation from at least: a nominal aperture mode of operation, in which only a plurality of radiating elements of the inner nominal region are selectively activated; and an extended aperture mode of operation, in which a plurality of radiating elements of both the inner nominal region and the extended region are selectively activated; and determine the antenna activation pattern for the selected mode of operation. select a mode of operation from at least: a nominal aperture mode of operation, in which only a plurality of radiating elements of the inner nominal region are selectively activated; and an extended aperture mode of operation, in which a plurality of radiating elements of both the inner nominal region and the extended region are selectively activated; and a nominal aperture mode of operation, in which only a plurality of radiating elements of the inner nominal region are selectively activated; and an extended aperture mode of operation, in which a plurality of radiating elements of both the inner nominal region and the extended region are selectively activated; and determine the antenna activation pattern for the selected mode of operation.