Design of chipless RFID tags using multi-mode resonators

Developments in RFID (Radio Frequency Identification) technology which has an important place in modern wireless communication systems, are very important for tracking and identification of objects. RFID technology has significant advantages compared to barcode technology which is used in almost every sector today, in terms of its wider sight and long reading range performance. In this context, studies to increase code variation in low-cost chipless RFID tag designs have gained importance. In this thesis, circuit models of a dual-mode resonator that can generate three frequency codes with an easy method, triple-mode resonator that can generate five frequency codes, and triple-mode resonator circuit with coupling mechanism that can generate eight frequency codes have presented with their theoretical analysis for the chipless RFID tags. In order to increase the number of bits, multi-resonator circuits have been designed using the proposed resonator models. Chipless RFID tag designs have been presented by integrating wideband monopole antennas developed to cover bit frequencies to the input and output ports of these circuits. To test the performance of the proposed tags, tags with different frequency codes have been fabricated and successfully tested under different circumstances.