Analysis of the disk-loaded spherical annular-ring microstrip antenna

It has been found that, by combining several patches with similar resonant frequencies on the same or different layers of the microstrip structure, the antenna bandwidth can be broadened. The disk-loaded spherical annular-ring microstrip antenna is analysed using a full-wave analysis and a moment-method calculation. The antenna is excited by a coaxial probe. Numerical results of the input impedance and voltage standing wave ratio (VSWR) are presented. The related numerical results of the single patch case are plotted for comparison. The radiated fields and the cross-polarization characteristics are also calculated and discussed.