Chipless RFID multiresonators fabricated by Fill until Full (FuF) technique

For simple and low cost manufacturing process of electronic circuits and components, Fill until Full (FuF) technique was introduced. The application of FuF is demonstrated through the fabrication of 3-bit multiresonators for chipless RFID transponders. Spiral resonators were located along microstrip on Teflon substrates. Silver conductive ink was employed. Each resonator operates as a stop-band filter at a designed frequency. The designed frequencies are 1.94, 2.58 and 2.49 GHz, for bit 2, 1 and 0, respectively. Measured values of |S₂₁|² within ±100 MHz frequency band show that the threshold for logic `0´ and `1´ are -2.77 dB and -0.92 dB, resulting in 1.85 dB margin for distinguishing the different logic data. In conclusions, FuF is verified to be suitable for the application. The proposed technique and the fabricated multiresonator components are capable of contributing further expansion in chipless RFID technology.