Characteristics of arrays of rectangular stepped horns with dielectric-loaded walls in one plane

Planar antenna arrays of rectangular waveguides radiating through step tran sitions whose walls are loaded in one plane with a dielectric so that the h ard-wall boundary condition is satisfied are considered. The analysis uses the multimode scattering matrix method. It is shown that finite waveguide s ections with hard walls are capable of removing the blindness effects inher ent in arrays of waveguides with a small cross section and homogeneous fill ing; the matching of the array remains sufficiently good. Characteristics o f H-plane sectoral-horn and pyramidal-horn arrays are also calculated. The sectoral horns with hard walls are found to operate in a wider frequency ba nd than similar sectoral box horns. The efficiency of hard-wall pyramidal-h orn arrays is 2 dB higher than that of arrays of similar square box horns.