Hemispherically capped thick cylindrical monopole with a conical feed section

The axis boundary condition scalar potential integral equation is used to study the hemispherically capped thick cylindrical monopole with a conical feed section. The monopole is perfectly conducting and is fed by a coaxial line whose outer radius is connected to an infinite perfectly conducting ground plane. One approximation in the equation is that the field across the coaxial aperture is approximated by the fundamental TEM coaxial line mode. The integral equation is numerically solved by the moments method using entire domain basis functions with delta weights. A simple way for checking the convergence of the solution that needs no new integrations is given. The theoretical current distributions, input admittances, and radiation patterns are given for a thin, moderately thick, and thick monopole with and without a conical feed section. This feeding section simplifies the matching of the antenna to conventional signal generators and improves the high frequency characteristics of the monopole.