Design, analysis and experimental test results of dual-band circularly polarized (CP) microstrip patch antenna are presented. Effects of inserting slits at
the edge of antenna to obtain dual-band and loading slot at center of patch to achieve circular polarized radiation also are discussed. Theoretical analysis of the proposed antenna with four rectangular slits at the edge and a slot at center of patch shows that dual-band property can not
be achieved. To overcome this problem, we can use four T-shape slits instead of rectangular ones. HFSS high frequency simulator is used for analysis of the antenn The antenna is implemented on a FR4 substrate with permittivity about 4.1 and thickness 1.6 of millimeter Theoretical results are in good agreement with experimental results
