Design and Performance Study of Single and Multi-Layered Fractal Based Miniaturized Patch Antennas for 2.4 GHz Applications

Abstract

The design and characterization of single and multilayered miniaturized microstrip antennas resonating at 2.4 GHz are proposed. The miniaturization is accomplished by fractal Defected Ground Structure (DGS). The DGS used for miniaturization is a Modified Minkowski Fractal DGS (M-MFDGS). The proposed size reduction process with M-MFDGS follows the selection of the best antenna configuration and its design parameters through sensitivity analysis and pattern search optimization. Microstrip patch antennas with three different feeding mechanisms are considered here to validate the effect of DGS over the size reduction and performance improvement. Incorporating M-MFDGS in three antennas, the first one with microstrip line feed accomplishes a maximum patch area reduction of 70% among the three proposed structures with a gain of 1.43 dBi. Likewise, with a slightly higher dimension than the first structure, the second antenna with proximity-coupled feed achieves a higher gain (5.11 dBi) and bandwidth (110 MHz). Although the size reduction in the third antenna with aperture-coupled feed is a little less it has the highest gain (5.91 dBi) among all the three. All three compact antennas are physically fabricated and the simulated results are validated with the measured results.