This work describes the integration of commercially available packaged radio frequency microelectromechanical system (RF MEMS) switches with radiation pattern reconfigurable microstrip antennas. Most applications of RF MEMS switches consider the switches as only circuit elements. In contrast, the implementation of packaged switches in this particular antenna must address not only the simple open/closed behavior of the switches but also their impact on the radiation characteristics of the reconfigurable antenna. Here, two Radant MEMS single-pole single throw (SPST) SPST-RMSW100 (packaged RF MEMS) switches are used to reconfigure the radiation patterns of a resonant square spiral microstrip antenna between endfire and broadside over a common impedance bandwidth. Switch insertion, matching network design, and other issues are addressed. Results for both simulated and measured antennas, as well as recommendations for future work in this area, are provided. \ 2006 IEEE.