Chip and antenna impedance measurement for the design of passive UHF RFID tag

The ever growing interest in the Radio Frequency Identification (RFID) technology has given rise to countless new applications. This senario has initiated the development of low cost RFID tags. This work introduces the measurement of the chip and the antenna impedance for the design of RFID labels. Those two measurements are critical in the design of passive UHF RFID tags as performances are strongly related to the impedance matching. A novel measurement technique based on a LRL calibration is proposed for the impedance measurement of RFID chip impedance. Then the measurement of the antenna impedance over a ground plan is introduced. It is illustrated with the measurement of a dipole antenna matched to the chip impedance using a tuning series inductive meandered line.