Variable permittivity dielectric material loaded stepped-horn antenna

332.5 Antenna CharacteristicsAntenna characteristics are determined based on the solution for the magnetic currentdensity across the aperture and the aperture field coefficients. Far field pattern computationis done using electric vector potential with the knowledge of magnetic current densityacross the aperture.The input reflection matrix at the feed waveguide including the aperture discontinuityis given by _Reflection coefficient due to the incident TE 10 mode is defined asThe radiation intensity in normalized form is calculated using far field components ofelectric field as followingGain is defined a:where Pin is the incident power at the input section of the horn.The directive gain of the antenna iswhere P rad is radiated power. The aperture efficiency is a figure-of-merit which indicates-how efficiently the physical area of the antenna is utilized. The aperture efficieny is afunction of many factors. Among them is the most prominent parameters are the amplitude