| 摘要 |
<p>A transponder preferably with the dimensions of a credit card receives signals from a reader, modulates them, and reflects them back to a reader to pass the information contained in the transponder to the reader. First conductive material (18) is disposed on the first surface of the dielectric member (12) at a first end of the member. Second conductive material (20) on the second opposite surface of the dielectric member at the second end of the member defines a dipole with the first material. The second material is preferably triangular in configuration. An electrical circuitry on the dielectric member (12) produces reflected signals modulated at a particular frequency from the signal transmitted by the reader to pass information contained in the transponder to the reader. The dipole (18,20) is electrically coupled with the conductive material (24, 25) and enhance an impedance match between the dipole and electrical circuitry. The conductive material has a first low impedance portion split into two parts (24, 25) connected in parallel to provide an extended effective length in a relatively small distance, and has a second portion, preferabiy a "pigtail", of substantially higher impedance than the first portion connected in series with the first portion. The first portion converts the antenna impedance to a low value and the second portion converts the low impedance to the impedance of the electrical circuitry module.</p> |
