High performance low profile antennas

An antenna array apparatus comprising:

• an elongated waveguide having a multi-layer substrate, the substrate having a major axis, a minor axis, an excitation end and a load end, the substrate comprising two or more layers of dielectric material, at least one of the layers being a selected dielectric layer that is spaced apart from an adjacent dielectric layer by an adjustable distance;
• a control element, connected to at least one of the dielectric layers, and to thereby electrically scan a radiated beam angle by adjusting the adjustable distance between the selected dielectric layer and the adjacent dielectric layer;
• one of the dielectric layers being an outer dielectric layer;
• and
• an array of radiating antenna elements disposed on and electrically coupled to the outer dielectric layer at regularly spaced apart positions along the major axis.