Impedance matching a cylindrical monopole at the centre of a circular ground plane

The input impedance and impedance matching of a cylindrical monopole at the center of a circular ground plane are summarized. The monopole length, radius, and ground plane radius are varied between $ 0.23\lambda$ to $ 0.26\lambda$, $ 10^{-5}\lambda$ to $ 5\times 10^{-3}\lambda$, and $ 0.2\lambda$ to $ 2.0\lambda$, respectively, where $\lambda$ is the wavelength. Using numerical results from the Finite Element Method, previous theoretical impedance results for an infinitesimally thin element are shown to poorly model wires of practical thicknesses over mobile communication frequencies. To obtain good antenna impedance matching, i.e., $ S_{11}\leq$-10dB, for any ground plane radius greater than $\lambda/2$ and any practical monopole radius, a monopole length of $ 0.24\lambda$ should be used.