End-fire hybrid array antennas

A heuristic approach useful in the design of end-fire array antennas is described. When an array is scanned "beyond end fire," the last elements of the array, in the direction of the end-fire beam, generally receive net power transmitted by other elements of the array. This received power might conceivably be recirculated and reradiated at the price of substantial complexity in the feed network. It is relatively simple to absorb this power in appropriate resistive loads at the price of reduced gain. The resulting end-fire antenna is a hybrid-array consisting of two classes of elements: elements excited directly and elements excited parasitically. A compromise termination of these parasitic elements in reactive loads especially determined to preserve desired pattern characteristics is examined.