A study of variable beamwidth horns

This paper presents results from a project studying horn antennas in which a change in beamwidth is produced by a corresponding change in an electronically variable input parameter. The beamwidth of a horn can be altered by changing either the effective transmitting aperture, and/or by modifying the amplitude/phase distribution over it. Initial experimental prototypes successfully demonstrated the feasibility of achieving as much as a 1:3 change in beamwidth with H-plane sectoral horns. The technique has now been successfully extended to pyramidal horns to produce variable patterns in both principal planes