Abstract: An antenna formed by an array of dipole elements fed by a triplate or stripline system is provided with earthed posts between the dipoles. These posts prevent radiation from one dipole being received by others thereby improving the antenna efficiency.

Abstract: A triplate fed slot antenna in which a conductive sheet has a slot with a length of .lambda., where .lambda. is the wavelength of a signal intended to be radiated from or received by the antenna. A triplate feed structure is coupled for feeding the slot. The triplate feed structure includes two outer conductors defining walls of a resonant cavity backing the slot, and an inner conductor disposed in the cavity.

Abstract: An antenna capable of producing circularly polarized radiation is formed by two non-coaxial cross dipoles.

Abstract: An antenna includes an array of electrically conductive cells each having one open side and containing a radiating/receiving element. The conductive cells reduce mutual coupling between elements.

Abstract: An antenna arrangement consists of a dipole radiator which is fed via a Triplate three-layer transmission line. The dipole is arranged to radiate and receive plane polarized electro-magnetic radiation having a plane of polarization which is determined by the orientation of an elongate slot in the dipole radiator. The Triplate is coupled to the dipole so as to maintain a substantially constant impedance over a reasonably wide bandwidth. A large number of similar dipole radiators can be mounted side by side and fed from a common Triplate structure and in this latter case a common reflector is used for all dipoles and is mounted on the Triplate structure itself.