A 77 GHz polarization-agile radio frequency microelectromechanical system (RF MEMS) patch antenna integrated with single-pole single throw switches is presented. The polarization of the proposed antenna can be switched among linear polarization, right-hand circular polarization, and left-hand circular polarization. The RF MEMS antenna is fabricated on 25 mil alumina with permittivity of 9.8. The reflection and radiation parameters of antenna including return loss, radiation patterns, gain, and axial ratio are measured and are found to be in correlation with simulated results. The proposed work is useful for automotive radar applications. © 2020 Wiley Periodicals, Inc.