Mode-matching analysis of top-hat monopole antennas loaded with radially layered dielectric

A top-hat monopole antenna with homogeneous or inhomogeneous dielectric loading over a ground plane is considered. Mode-matching analysis with proper enforcement of edge conditions is applied to the problem. The results of this technique are verified through independent calculations of admittance as well as by comparison of fields across matching regions. Measurements were also taken for comparison with the results from the model. It is shown that dielectric loading can reduce the electrical size necessary for self resonance, but only at the expense of a large increase in radiation Q.