“…Thus when multimode elements are used they should be as large as the lattice allows. For a single polarization, bandwidth of .50% with VSWR 4 and scan over nearly a quarter hemisphere has been obtained (Tsandoulas, 1972(Tsandoulas, , 1980). An iris can be used in each waveguide radiator, below the aperture, in addition to dielectric plugs, as an aid to matching.…”