Radiation characteristics of a dielectric sphere loaded corrugated E-plane sectoral horn

The experimental results of the radiation characteristics of a dielectric sphere in front of a corrugated -plane sectoral horn together with the design aspects of the horn are reported. The experiments were carried out with the test antenna system consisting of dielectric (paraffin wax) spheres kept offset at the minimum input VSWR position in front of the horn excited in the balanced HE11mode. The test results have shown that such a feed system produces radiation patterns with reduced sidelobe levels and increased on-axis gain with reduced 3-dB beamwidths as compared to the same horn radiating in free space. The feed system may also produce a low input VSWR and can be used as a variable beamwidth feed for praraboloidal reflectors.