EVALUATION OF RESONANT-FREQUENCY OF A CYLINDRICAL PROBE-FED DR ANTENNA

The eigenmode expansion method is used to evaluate the resonant freque ncy of a probe fed cylindrical dielectric resonator (DR) antenna, whic h radiates above an infinite conducting ground plane. A parallel groun ded conducting plane is added above the DR, thus allowing the use of c ylindrical harmonic field expansions in the regions between the two pa rallel ground plants. The eigenmode expansion coefficients are found b y enforcing the boundary conditions at conducting surfaces and regiona l interfaces. Then, from the induced currents on the probe surface, th e input impedance and the resonant frequency of the DR antenna are eva luated. The results are compared with those of a previous configuratio n which has no upper ground plane. It is found that the deviation of t he calculated resonant frequency is less than 2% for epsilon(r) > 9.