2-D LTCC Van Atta Arrays with Frequency-Domain Encoding for Millimeter Wave Chipless RFID

The millimeter wave two-dimensional Van Atta arrays, designed for data encoding in chipless RFID systems, are presented in this paper. The arrays, fabricated using LTCC technology, are optimized for the 24 GHz band. Frequency-domain data encoding is achieved using microstrip resonators integrated with the lines of the array feed network, which selectively attenuates signal transmission at frequencies determined by their lengths. The fabricated chipless RFID tags, with dimensions of 24 x 24 mm, feature an information encoding capacity of up to 2 bits and an RCS level of up to -28 dBsm. To the best of the authors' knowledge, this is the first time that practical realization of 2-D Van Atta arrays integrated with resonant circuits for data encoding have been presented.