Abstract: An antenna system, comprising: a phased array antenna (4); and a dielectric lens arrangement (6), for example a single solid dielectric lens (6) comprising a substantially spherical convex surface (12) and a concave surface (14); wherein the dielectric lens arrangement (6) is arranged to magnify the effective aperture of the phased array antenna (4). The concave surface (14) is positioned within the near field of the phased array antenna (4). The phased array antenna (4) is operated at a frequency greater than or equal to 50 GHz. The antenna system retains some ability to electronically scan the beam. The antenna system may be for transmission and/or reception. The antenna system may be used for example for communication between two vehicles.

Abstract: A feed structure for a wearable antenna incorporates a microstrip transmission line designed for mounting on opposite sides of a fabric. The transmission line has a perforated ground plane which reduces capacitance and offers an appropriate impedance, even when the fabric is thin, and allows the use of a relatively robust line conductor having a width of 3 mm or 5 mm or more. The ground plane can be extended to provide the ground plane of a balun and the material of that ground plane can in turn be extended to provide the wearable antenna.

Abstract: A wearable antenna assembly incorporates a coplanar waveguide feed in one of the arms of a two-arm spiral antenna. The antenna has relatively high impedance compared with the feed line from a suitable radio but the coplanar waveguide feed is simply modified to provide a quarter-wave transformer adjacent to the feed connection to the antenna and at least one further impedance transformation step on a tangential extension of the feed at the outer edge of the spiral antenna.

Abstract: A projectile detection system, and method of detecting a projectile (for example a bullet), for use on a vehicle (100) (for example a helicopter), the projectile detection system comprising: a radar antenna array (4) arranged to transmit and receive microwave signals so as to provide a plurality of detection segments (40, 42, 44, 46) of a volume of airspace (38); one or more processors (3) arranged to: determine which segments (40, 42, 44, 46) microwave signals reflected by a projectile (10) are received from; determine timing information relating to a time order in which the received microwave signals are received; and determine directional information relating to a direction of travel of the projectile (10) using the determined segments (40, 42, 44, 46) and the determined timing information; wherein the microwave signals have a frequency between 1 GHz and 30 GHz.

Abstract: A wearable antenna assembly incorporates a coplanar waveguide feed in one of the arms of a two-arm spiral antenna. The antenna has relatively high impedance compared with the feed line from a suitable radio but the coplanar waveguide feed is simply modified to provide a quarter-wave transformer adjacent to the feed connection to the antenna and at least one further impedance transformation step on a tangential extension of the feed at the outer edge of the spiral antenna.

Abstract: A feed structure for a wearable antenna incorporates a microstrip transmission line designed for mounting on opposite sides of a fabric. The transmission line has a perforated ground plane which reduces capacitance and offers an appropriate impedance, even when the fabric is thin, and allows the use of a relatively robust line conductor having a width of 3 mm or 5 mm or more. The ground plane can be extended to provide the ground plane of a balun and the material of that ground plane can in turn be extended to provide the wearable antenna.

Abstract: A projectile detection system, and method of detecting a projectile (for example a bullet), for use on a vehicle (100) (for example a helicopter), the projectile detection system comprising: a radar antenna array (4) arranged to transmit and receive microwave signals so as to provide a plurality of detection segments (40, 42, 44, 46) of a volume of airspace (38); one or more processors (3) arranged to: determine which segments (40, 42, 44, 46) microwave signals reflected by a projectile (10) are received from; determine timing information relating to a time order in which the received microwave signals are received; and determine directional information relating to a direction of travel of the projectile (10) using the determined segments (40, 42, 44, 46) and the determined timing information; wherein the microwave signals have a frequency between 1 GHz and 30 GHz.

Abstract: An antenna system, comprising: a phased array antenna (4); and a dielectric lens arrangement (6), for example a single solid dielectric lens (6) comprising a substantially spherical convex surface (12) and a concave surface (14); wherein the dielectric lens arrangement (6) is arranged to magnify the effective aperture of the phased array antenna (4). The concave surface (14) is positioned within the near field of the phased array antenna (4). The phased array antenna (4) is operated at a frequency greater than or equal to 50 GHz. The antenna system retains some ability to electronically scan the beam. The antenna system may be for transmission and/or reception. The antenna system may be used for example for communication between two vehicles.

Abstract: An antenna is provided, in combination with an associated switch array, the antenna comprising a number of antenna elements mounted above a ground plane for providing coverage over a predetermined range of angles in azimuth using a number of beams. Each of the antenna elements is connected to a switch in the switch array and the switch array is operable to connect selected pairs of the antenna elements to a signal path to thereby generate each of the different beams, at the same time connecting unselected antenna elements to ground.

Abstract: Phased array antennas, in particular highly coupled arrays of dipoles having a vertical electrical feed structure. A phased array antenna including a plurality of antenna elements and a plurality of electrical feed structures, wherein each feed structure serves an antenna element and each electrical feed structure is at least partially substantially surrounded by a ferrite element.

Abstract: This invention relates to a radiating element 20 for use in array antennas. The radiating element 20 is of simplified design and comprises a front region 26 and a rearward region 28 that are preferably substantially rectangular, which permit higher frequency limits than more conventional Vivaldi elements while maintaining the lower frequency limit. Additionally, by deployment of an array of a plurality of such elements 20 such that no gaps are formed between adjacent elements 20 along the array antenna, very wide bandwidth can be obtained using the array.

Abstract: An antenna is provided, in combination with an associated switch array, the antenna comprising a number of antenna elements mounted above a ground plane for providing coverage over a predetermined range of angles in azimuth using a number of beams. Each of the antenna elements is connected to a switch in the switch array and the switch array is operable to connect selected pairs of the antenna elements to a signal path to thereby generate each of the different beams, at the same time connecting unselected antenna elements to ground.

Abstract: This invention relates to a radiating element 20 for use in array antennas. The radiating element 20 is of simplified design and comprises a front region 26 and a rearward region 28 that are preferably substantially rectangular, which permit higher frequency limits than more conventional Vivaldi elements while maintaining the lower frequency limit. Additionally, by deployment of an array of a plurality of such elements 20 such that no gaps are formed between adjacent elements 20 along the array antenna, very wide bandwidth can be obtained using the array.