Active Minimization Of The Sidelobes Of Radiating Apertures

A novel technique for suppressing sidelobes as well as increasing the mainlobe level of radiating apertures is presented. The technique involves placing a separately excited wire along the diffracting edge of the aperture so as to enhance the mainlobe and to suppress the sidelobes of the radiating aperture. The beamwidths of the resulting E and H planes of a circular waveguide loaded by an active wire loop are found to be almost identical in a particular experimental case. Furthermore, the E and H plane patterns approach each other since the sidelobe levels are decreased significantly in the E plane and by about the same amount as they are increased in the H plane. A significant increase in the main-to-sidelobe ratio is also obtained when this technique is applied to radiating fields from circular apertures in a full conducting plane and to the diffraction from apertures between two semi-infinite conducting wedges. © 1989 Taylor & Francis Ltd