Low cost folded chipless tag for millimeter-wave applications

A simple made RFID chipless tag by folding its transmission line (TL)structure is presented. Dual polarized antennas are used to assure the back-scattering signal. The TL mutual coupling and meander shape are designed to fit the required number of bits into the specific frequency band. To achieve a practicality and low cost chipless RFID tag, the parametric study of folded multi-layer tag is also presented. A tag design with three elements, representing three bits, is performed. The elements operates in the frequency range of 55 GHz -59.5 GHz. Besides the design technique, it is demonstrated that a multi-frequency can be used for coding increase the chipless RFID tag capacity. Therefore, the chipless tag design has shown to be useful for frequency selective applications.