Analysis of the microstrip disk antenna element
Abstract
The circular microstrip antenna element is formed by a radiating disk closely spaced above a ground plane. It is modeled as a cylindrical cavity with magnetic walls which can be resonant in the transverse magnetic (TM) modes. The far fields and the radiation conductances for different mode structures have been calculated assuming a magnetic line current flowing along the perimeter of the disk. The directivity of a disk antenna excited in the dominant mode is between 4.8 dB and 9.9 dB, depending on the size. Losses, due to imperfect supporting dielectrics and to the finite conductivity of the conductors, have been derived by means of a perturbation technique. Graphs are given for design purposes showing the input impedance, the Q factor, and the radiation efficiency at resonance for different modes and thicknesses. The airfilled microstrip antenna has the highest efficiency and the broadest bandwidth at a given resonant frequency.
 Publication:

IEEE Transactions on Antennas and Propagation
 Pub Date:
 September 1979
 DOI:
 10.1109/TAP.1979.1142159
 Bibcode:
 1979ITAP...27..660D
 Keywords:

 Antenna Design;
 Antenna Feeds;
 Disks (Shapes);
 Microstrip Antennas;
 Microwave Antennas;
 Antenna Radiation Patterns;
 Design Analysis;
 Directivity;
 Electrical Impedance;
 Far Fields;
 Power Efficiency;
 Q Factors;
 Radiators;
 Resonant Frequencies;
 Wave Excitation;
 Communications and Radar