| 摘要 |
<p>A resonant tag circuit (Figs. 1-6 and 8-9) having at least one resonant frequency is operative in an electronic security system (Fig. 7) in which the tag circuit is sensed and electronically deactivated (Figs. 13, 16) to destroy the resonant characteristics of the tag circuit at the detection frequency. The tag circuit is constructed such that the capacitor plates (10, 12, 22, 24) are closer to one another at a selected point (20, 32). This provides a breakdown mechanism within the resonant structure of the tag. A deactivator (Fig. 16) provides electromagnetic energy at a resonant frequency of the tag circuit of sufficient energy to cause electrical breakdown (Figs. 10-12) at the selected point (20, 30). This deactivates the tag circuit by causing vaporization of a conductive area (Fig. 11) or short-circuiting of the capacitor plates (Fig. 12) to destroy the resonant properties of the circuit.</p> |
