The directional coupler antenna

The combination of four broadband 3 db directional couplers and four radiating elements into an antenna for direction-finding purposes has been investigated. Under theoretical conditions, two overlapping beams with constant crossover level and variable crossover slope over an infinite frequency band can be obtained. All four radiators are active in producing each of the two main lobes for simultaneous comparison, thereby providing the pattern effect of two antennas of similar dimensions. Practically, an antenna pattern with crossover level 3 to 5 db below beam maximum, and pointing accuracy of\pm0.75degrees over a 2. 2 to 1 bandwidth has been achieved.