An experimental method for obtaining device parameters of SAW RFID tags

To make a SAW radio frequency identification (RFID) tag carry more information, it should consist of several reflectors. It is important to exactly know the related parameters of the tag in selected frequency band, such as propagation loss when it propagates on free surface of a SAW device, transduction coefficient of the IDT (interdigital transducer), and reflection and transmission coefficients of reflectors with different numbers of electrodes, widths of electrodes, or both. In this report, we propose a novel method which can obtain these parameters through experiments and data processing. We develop a new test-device structure with different numbers and widths of electrodes of reflectors fabricated in one device. All related tag parameters can be obtained simultaneously, which can greatly reduce the tag design cost.