Resonance of the axial-symmetric modes in microstrip disk resonators

Abstract

Three methods have been used to calculate the resonant frequencies for the axial‐symmetric modes in the microstrip disk resonators which also have the application as radiating antennas. The variational Galerkin’s method provides the most accurate result for the estimation of both the real and imaginary parts of the resonant frequency shifts with judicious choices of basis functions. The iterative approach gives good results for the imaginary part of the frequency shift and very crude approximations for the real part. The perturbation formula is the most efficient in computational time and is useful for sufficiently large permittivity for the substrate material and small ratio of substrate thickness to disk radius. To illustrate the application of the circular microstrip disk as a radiating antenna, the radiation pattern for the axial‐symmetric mode is also plotted.