DIELECTRIC LOADING OF A SMALL RIDGED CAVITY-BACKED SLOT ANTENNA.
The effects are studied of dielectric loading on the frequency of operation, input impedance, and aperture field distribution of a ridged, cavity-backed slot antenna. The transverse slot is cut in the flat broadwall of a deep, single-ridge waveguide cavity, when the cavity is excited by the center conductor of a coaxial transmission line. The role of the input-probe position in matching the antenna is demonstrated. The experimental parameters are summarized in tabular form. It is concluded that dielectric loading reduces the operating frequency and improves the slot aperture efficiency. The input impedance level is controlled by the probe position. A lossy dielectric increases bandwidth (reduces Q) at the expense of efficiency.