Abstract: This paper presents a new method for designing a dual frequency patch antenna with circular and linear polarizations. Dual frequency operations are behaved by etching two narrow slots close to the radiating edges of a rectangular patch. The circular polarization at the lower resonant frequency of the dual frequency antenna can be achieved by setting a perturbation segment at an appropriate location in the patch element, and placing the feed point on the diagonal axis. Several experimental results of a designed antenna show the good characteristics for circular and linear polarizations at both resonant frequencies.

Key words: slot patch antennas, dual-frequency, linear polarization, circular polarization