Chipless RFID tag based on split-wheel resonators

A completely passive chipless RFID tag is proposed. The tag utilizes the scattering from an array of split-wheel like compact electric field coupled resonant structures resonating at different frequencies. When interrogated with a broadband plane wave signal, the reader detects the RCS signature generated by each of the resonators and with n resonators, effectively 2ⁿ-1 items can be tagged and identified. As the proposed resonator structure allows easy detuning of resonance and has relatively narrow resonance bandwidth, utilizing the UWB frequency band, it is possible to realize a fully printable chipless tag with large information capacity. Direct printing of such tags using metal loaded ink with low cost lithographic printing techniques on low cost paper or polymer substrate will lead to a potential technology, which can replace optical barcode in the long run.