Toward reliable readers for chipless RFID systems

We report in this paper several techniques to make chipless RFID systems more reliable in order to overcome some drawbacks such as detuning effects, unwanted echoes from the surrounding environment as well as the spurious interferences due to concurrent wireless systems in the ISM bands. As a figure of merit, we show through the implementation of signal processing techniques and by using optimized design that reading a chipless tag on water bottles or on a pack of metallic cans is possible and reliable. Such readings are usually not possible by using conventional designs and systems. The various techniques proposed are tested with the help of simulations, and measurements in a practical indoor environment.