| 摘要 |
A device 30 detectable by radio-frequency radiations, the device comprising two electrically-connected metallic cavity regions , the cavity regions in combination having an associated distributed inductance and distributed capacitance, wherein: a first one of the cavity regions 1 is defined between a pair of plates of relatively large plate separation and is loaded with a ferrite material 18, the first cavity region having a relatively large distributed inductance; and a second one of the cavity regions 35 is of relatively small plate separation and is filled with a dielectric 17, the second cavity region having a relatively large distributed capacitance. The second cavity region may be wound around the first cavity region to form a circuit with resonant frequency corresponding with an operating frequency of a reader (possibly in the HF or UHF bands). The first cavity may comprise two, substantially parallel, conductors which are electrically connected at one end 4. The device is aimed at use on conductive surfaces, such as metals, where other tags might be unreadable. |
