Planar dielectric image line antenna arrays using Y-junctions

Dielectric image line (DIL), a rectangular dielectric cylinder on a ground plane, is an open low-loss transmission line for millimeter-wave frequencies. By introducing periodic gratings, linear leaky wave antenna arrays have been made from DIL. A DIL power divider can be constructed by widening the width of its input line and then splitting the dielectric into two output arms. Two planar arrays fed by dielectric image line Y-junctions are described. Planar arrays are used to reduce the radiation patterns' beamwidth in two orthogonal planes. Beam scanning, using an electro-mechanical actuator, is demonstrated for one of the planar antennas.