The dual-band chipless RFID sensor is proposed to employ as a wireless material quality monitoring application. A printed perpendicular rectangular loop tag and a printed concentric rectangular loop tag are designed and optimized using the CST Microwave Studio program. The chipless RFID sensors are located on a material surface to determine qualities of a material under test. From numerical results, it is found that the proposed dual-band chipless RFID-sensor has a significant different radar cross section (RCS) compared with the single-band one. Therefore, both RFID sensors can be used together in the material quality monitoring system to improve the accuracy.
