Calculation of the Bandwidth of Microstrip Resonator Antennas

In this paper one presents an analysis of the bandwidth of microstrip resonator antennas in function of the antenna parameters. Starting from the general expression for the quality factor of a resonator, it will be proved that the bandwidth of a microstrip resonator antenna is directly proportional to the thickness of the substrate, to the square of the resonant frequency and inversely proportional to the square root of the relative permittivity of the substrate material. Comparing the theoretical results with experimental data one finds a good agreement.