Improvement of RCS response of U-shaped strip-based chipless RFID tags

We present a modification of an arrangement of 20-bit chipless tag composed of 20-element array of U-shaped strip scatterers that significantly improves radar cross section response in terms of uniformity and amplitude robustness over the operational frequency range 2 to 4 GHz. This modification is based on the inter-arrangement of array elements in order to eliminate the strong coupling between neighboring resonance elements. The tag has been measured in a mono-static arrangement with one double-ridge horn antenna, and provides a significantly improved homogeneity of the RCS response compared to an original array of folded dipole resonators. The reliability of the reading of coded information is highly improved.