Variable permittivity dielectric material loaded stepped-horn antenna

34taper and the phase distribution across the aperture. Aperture efficiency, Cap is defined aswhere A is the physical area of the aperture and Do is the directivitiy.apertureThe maximum radiation intensity (Umax) occurs at 6 = 0, therefore directivity of theThe cross-polar radiation characteristics are dependent on the difference between theE- and H- plane patterns. The co- and cross-polarization pattern components Eco(θ, q5)and Ecross(θ , 0) are given by the relations, with a definition of cross-polarization based on' Ludwig's third definition' [19],