Abstract: With the development of wireless communication, some new performance requirements on the antennas have emerged. The applications of dual frequency antennas are more and more popular new. Some solutions to attain dual frequency operation of patch antennas are reported in this paper, such as Orthogonal mode, Multi patch, Reactively loading and some others. With HFSS simulating, one dual frequency antenna with two patches is designed. The development trend of dual frequency patch antennas is also discussed.