Time-Domain Ultrawideband Chipless RFID Readers

This article evaluates time-domain techniques for the applications of ultrawideband (UWB) chipless radio frequency identification (RFID) readers. In UWB time-domain readers, the chipless RFID tag response to a UWB pulse excitation is simultaneously measured in time domain and then the frequency-domain signature of the tag is calculated by a time-to-frequency conversion method such as fast Fourier transform. A 32-bit UWB chipless RFID tag is designed and three time-domain readers based on impulse radio UWB, chirped-pulse Fourier transform microwave (CP-FTMW), and dual-comb techniques are analyzed and implemented by using microwave equipment including arbitrary waveform generator, network analyzer, and high-speed oscilloscope. It is demonstrated that CP-FTMW reader is a fast, accurate with high signal-to-noise ratio, and high-frequency resolution time-domain technique. Dual-comb reader is slower, however, it offers a viable solution for a low cost and potentially miniaturized and portable chipless RFID readers.