By Ken Greenwood, TRM Microwave
Beamforming networks for antennas have evolved since the 1960's. Early designs were typically fixed-beam architectures, although newer configurations include complex adaptive beamforming networks. This brief presentation reviews the origins of the technology, and offers several example circuit topologies of passive microwave beamformers.
Beamforming networks support multiple-beam antenna systems in such applications as multiple-beam jamming and phased-array radars. In many cases, beamforming is achieved by combining signals from a set of non-directional antennas to simulate the higher gain of a larger single antenna. The feed network to the antennas allows beam steering without having to physically move the antennas.