Abstract: A portable antenna with a housing in which the antenna is held when not in use, and a mechanism to cause the antenna to pop-up from, and sit on top of, the housing when it is to be used. The mechanism can function to collapse the antenna into the housing when not in use.

Abstract: A radar surveillance system is described in which the radar beam re-visits each area of interest after a short period of time, by electronically reconfiguring a scanned beam to an offset position for an interleaved sub-dwell, within a scan period. This ‘look-back’ capability, where the area under test is re-visited after approximately 1 second, allows the natural de-correlation of sea clutter to take place between the initial and look-back samples of the surveillance area. The re-visit time can be adjusted to best exploit the de-correlation characteristics of the sea clutter return.

Abstract: A portable antenna is disclosed that can be collapsed into, and erected from, a housing. There is also a pull cord mechanism arranged, when pulled, to cause the antenna to revert between the erect or collapsed configurations. The pull cord extends from the antenna to a position in easy reach of the soldier's hand so that the antenna can be erected/collapsed remotely.

Abstract: An antenna is disclosed in which the radiating structure includes a meta-material having frequency selective properties. The frequency selective properties of the meta-material enable multiple antennas each designed for operation at separate frequencies and each having such meta-materials to be placed in close proximity without affecting each other. This can be advantageous if for example a large number of antennas are to be placed in a small area such as on a vehicle or small building.

Abstract: A mechanism is disclosed to dismantle/erect a portable antenna that includes a linkage between radial driven elements and radial ground plane elements of the antenna which acts to cause them to move together between a collapsed and an erect arrangement.