A strain sensor based on a microstrip antenna has as principle of operation the relationship between an applied deformation and the resonance frequency shifts. This paper proposes a curvature sensor based on a rectangular microstrip patch antenna with plastic dielectric substrate and two operation bands around 2.6 and 6.1 GHz. Experimental test with different curvature radius were performed (from a curvature of 0 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> to a curvature of 40 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ) The experimental results were compared with results obtained in numerical simulations, where a good match for small values of curvature was found. The proposed sensor obtained a sensitivity of 1.78 and 2.41, and the range of operation was 21 and 67 MHz. The sensitivity of the sensor makes itself useful in Structural Health Monitoring (SHM) systems, in addition, plastic dielectric substrate features allows it to memorize applied deformations when the external force is gone.