Dual-Frequency Probe-Fed Rectangular Microstrip Antenna Design Using a Fuzzy Approach

-Dual frequency operation of antennas has become a necessity for many applications in wireless communication systems such as GPS, GSM services operating at two different frequency bands and services of PCS and IMT-2000 applications. Although there are various techniques to achieve dual-band operation from various types of microstrip antennas, there is no efficient design tool that has been incorporated with a suitable optimization algorithm. In this paper the cavity-model based simulation tool along with an intelligent fuzzy system is presented for the design of dual-band microstrip antennas, using multiple shorting strips placed between the patch and ground plane. Since this approach is based on cavity model, the multiport approach is efficiently employed to analyze the effects of the shorting strips on the input impedance. Then the optimization of the positions of shorting strips is performed via an intelligent fuzzy system, to achieve an acceptable antenna operation over the desired frequency bands. The antennas designed by this efficient design procedure were realized experimentally, and the results are compared. In addition, these results are also compared to the results obtained by the commercial electromagnetic simulation tool, FEM-based software HFSS by ANSOFT.