An innovative, flexible, planar waveguide antenna operating in dual-band mode for WLAN applications is proposed. This antenna has a simple topology, is compact, and is easy to manufacture fully using textiles. It involves loading by a composite right/left-handed waveguide to generate similar radiation patterns and low backward radiation in both operating bands. The latter property is extremely desirable for wearable applications as it avoids performance degradation due to dielectric coupling to the body, besides reducing possible health risks. Simulated and measured results indicate a good reflection and radiation performance agreement in both the 2.45 and the 5.4 GHz WLAN bands.