Evaluation of resonant frequency of a cylindrical probe-fed DR antenna

Abstract

The eigenmode expansion method is used to evaluate the resonant frequency of a probe fed cylindrical dielectric resonator (DR) antenna, which radiates above an infinite conducting ground plane. A parallel grounded conducting plane is added above the DR, thus allowing the use of cylindrical harmonic field expansions in the regions between the two parallel ground planes. The eigenmode expansion coefficients are found by enforcing the boundary conditions at conducting surfaces and regional interfaces. Then, from the induced currents on the probe surface, the input impedance and the resonant frequency of the DR antenna are evaluated. The results are compared with those of a previous configuration which has no upper ground plane. It is found that the deviation of the calculated resonant frequency is less than 2% for epsilon εr>9.