Displaced feed parallel plate antenna

A displaced feed antenna, operating at UHF, microwave, millimeter wave and terahertz frequencies, having a spaced conducting plate construction that incorporates electronically selectable feed points with associated antenna beam positions, which displaced feed antenna comprises:

• (i) a set of one or more beamforming configurations composed of layered, interlinking spaced conducting plates and conducting boundaries that are separated by cavities containing dielectric material or free space;
• in which adjacent layers of the interlinking beamforming configuration of spaced conducting plates are in the form of folded U-turn transitions at the point of reflection and overlapping step transitions at the point of transmission, and in which the step transitions are implemented as controlled gaps in the inner common plates, which, in the case of reflection is directly in front of a conducting reflecting boundary between the outer plates, and in the case of transmission is between conducting reflecting boundaries joining the two outer parallel plates to an inner parallel plate to either side of the overlap created by the gap;
• in which adjacent layers between the spaced conducting plates are filled with either the same or different dielectrics and contain refractive components to aid electromagnetic collimation or focusing;
• and in which the conducting and reflecting boundaries are contoured and spaced to provide good radio frequency matches between dielectrics of different dielectric constants and thicknesses;
• (ii) a set of one or more internal focusing means for each beamforming configuration to route radio frequency energy to or from the displaced feed points in receive and transmit modes respectively;
• (iii) a linear or curved array of displaced feeds which are for each beamforming configuration and which are in the form of reciprocal transitions between radio frequency transmission lines or waveguides for coupling radio frequency energy into, or from, the cavity between the plates;
• (iv) a selection means to allow definable overlapping regions of the focussing means to be illuminated for each beamforming configuration, by routing radio frequency energy to create a displaced feed, controllable in extent and position, within the array of displaced feeds;
• and
• (v) a radio frequency transition means for each beamforming configuration between spaced conducting plates to free space, allowing either single polarisations or dual polarisation operation.