AbstractThe performances of a quasilumped coupler with a pair of capacitors are first described. By varying the capacitance value of the capacitors, the coupler can operate at three different modes, including uncoupled‐line mode, quadrature hybrid mode, and T‐junction power divider mode. Based on the coupler design, a microstrip antenna with switchable polarization is developed and implemented. Experimental results demonstrate that the reconfigurable antenna can provide two linear polarizations and one circular polarization at one frequency. In addition, the antenna operating at each polarization state has good impedance matching and broadside radiation with low cross polarization. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:471–474, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27374