Abstract: RFID tags that must operate in the presence of ionizing radiation need to be radiation hardened in order to achieve reliable operation. This disclosure teaches several RFID tags that achieve radiation hardening without requiring the use of special-purpose radiation-hardened electronic devices. RFID tags typically use an antenna made of metal for achieving reliable radio communications. Radiation hardening is achieved by shaping the antenna such that the metal of the antenna acts as a shield for the radio circuits.

Abstract: An RFID tag communicating with a wireless reader interrogator on more than one frequency band. In one embodiment the tag contains independent sensor circuits for a ultra high frequency UHF band and a lower frequency band. The UHF antenna element used in the tag is a double-resonant antenna typically operating in the 860-960 MHz frequency range providing both near and far field sensitivity. Separate resonant antenna structures a the lower frequency band is connected in series with the UHF antenna substructure. The high frequency HF antenna element contains a coil for magnetic induction pickup of signals typically in the 7-14 MHz frequency band but can also be used for the entire spectral range 100 KHz to 100 MHz. The tag antenna is an integrated structure providing for operation in both the UHF and a lower frequency band. In a separate embodiment the tag is configured with the UHF double-dipole antenna structure only and operates in a single UHF band.