FDTD analysis of a slot-loaded meandered rectangular patch antenna for dual-frequency operation

The characteristics of a compact, dual-frequency antenna using the slot-loaded meandered rectangular microstrip patch are analysed. The theoretical analysis is based on the finite-difference time-domain (FDTD) method. The FDTD programs are developed and validated by available measurement results. Three different dual-frequency antennas, which include the slot-loaded rectangular patch, the slot-loaded meandered rectangular patch with five slits, and the slot-loaded meandered rectangular patch with 10 slits, are analysed and compared. It is shown that more slits and longer slits could lead to a smaller size of the dual-frequency antenna. The effects of slit lengths on the resonant frequencies and the frequency ratio of the slot-loaded meandered rectangular patch with 10 slits are shown. Several design curves are presented. The electric current distributions on the patch at two resonant frequencies are described, together with the results illustrating the electric field distributions under the patch. The radiation patterns of three dual-frequency antennas are also presented and compared