Abstract: A radio frequency identification tag is made with a printed antenna coil integrated on a flexible substrate, and an integrated circuit area of the substrate adjacent to the antenna coil for carrying circuit elements. The radio frequency identification tag is designed to be sufficiently robust to withstand the rigors of mail efficiency processing measurement applications. Robustness is accomplished by encapsulating a sensing circuit formed on the flexible substrate thereby forming a semi-rigid area on the substrate and leaving the antenna portion of the substrate flexible.