Briefly stated a tag includes a dielectric substrate having first and second opposite principal surfaces. An electrical circuit having an electrically conductive pattern is formed on at least one of the principal surfaces of the dielectric substrate, the conductive pattern including a gap which establishes...http://www.google.ca/patents/US6091607?utm_source=gb-gplus-sharePatent US6091607 - Resonant tag with a conductive composition closing an electrical circuit
