| 摘要 |
An improved homodyne receiver I/Q receiver for use in RFID and similar applications. The receiver uses a lumped constant network approach to eliminate costly and bulky couplers, circulators and distributed delay lines. A unique single-pole, four-throw ( sp4t) antenna switching arrangement is also provided. The receiver combines small size with improved efficiency and sensitivity to provide a practical, low-cost, hand-held receiver capable of operation over distances of approximately three to five meters. This allows the construction of a hand-held receiver having high performance (i.e., a long reading distance) and good discrimination (i.e., the ability to accurately read closely-spaced tags moving rapidly past a check point). When used with compatible RFID tags, the inventive system may also be used to alter the identification or other information stored within the RFID tags.
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