VIRTUAL SHORT CIRCUIT FOR PROVIDING REFERENCE SIGNAL IN RFID TAG

摘要

An RFID tag (10) including a virtual short circuit using a stepped impedance transformation from an open circuit or other known impedance point to provide a reference signal to an integrated circuit (22). The stepped impedance transformer (28) does not consist solely of a quarter wavelength transmission line. The stepped impedance transformer (28) may consist of first and second transmission lines (30,32) having different lengths and widths. The RFID tag (10) may also include an impedance matching circuit (20) which does not consist solely of a three-section transmission line. The matching circuit (20) may include a shorting stub transmission line.