The present invention relates to a radio-frequency identification tag (10) and a related method of operation, whereby the tag comprises an antenna (12) being adapted to draw a voltage from an externally applied RF field having a first frequency, and further comprises a tunable antenna resonant circuit (16) comprising a default resonance frequency and having tuning means (18) for shifting the resonance frequency to the first frequency, whereby non-volatile storage means (22) for storing frequency related data are provided, that are accessible at a reduced voltage level, which is below a “power-up” voltage level of the tag's operating unit (14).