AbstractThis article presents concepts for MEMS‐enabled low‐loss millimeter‐wave metal ridge waveguide phase shifters. Design examples for 80 GHz show 2.6 dB insertion loss for 90° continuously variable phase shift and 1.6 dB insertion loss for 140° phase shift, respectively. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1028–1030, 2010; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.25144