Automatically adjustable radio frequency carrier cancellation RFID reader-writer

Abstract

The invention discloses an automatically adjustable radio frequency carrier cancellation RFID reader-writer. The phase and the amplitude of a cancellation signal are adjusted through a vector modulator so that the leakage carrier of the cancellation signal and a receiving channel is enabled to be different for 180 degrees; the amplitude is enabled to be consistent with that of the leakage carrier of the receiving channel so as to realize radio frequency carrier cancellation; besides, the radio frequency carrier cancellation effect is inspected through a detector, and the radio frequency carrier cancellation effect is enabled to reach the standard by adjusting the phase and the amplitude of the vector modulator if the radio frequency carrier cancellation effect is not standard. The common problems of short read-write distance, saturated receiving channel and other defects of the common UHF RFID reader-writers can be compensated; and the defects of the present UHF RFID reader-writers can be greatly compensated and thus the RFID reader-writer has wide application prospect.

Description

technical field [0001] The invention belongs to the technical field of electronic information communication, and in particular relates to an RFID reader-writer with adjustable radio frequency carrier cancellation. Background technique [0002] Complying with the national military standard GJB7377.1-2011, the RFID reader with automatically adjustable RF carrier cancellation is a conventional passive backscatter RFID system, mainly composed of an RFID reader and a passive tag. However, due to the limitation of the size of the tag antenna, the tag reflection signal received by the RF front end of the reader is very weak. On the other hand, when the reader is receiving, it needs to continuously transmit continuous carrier waves to provide energy to the tags. In this way, the serious carrier leakage will cause the LNA of the RF receiving front end or the downlink with gain The front-end of the mixer is saturated, which seriously deteriorates the receiving signal-to-noise ratio, ...

AI Technical Summary

Problems solved by technology

However, due to the limitation of the size of the tag antenna, the tag reflection signal received by the RF front end of the reader is very weak

On the other hand, when the reader is receiving, it needs to continuously transmit continuous carrier waves to provide energy to the tags. In this way, due to serious carrier leakage at the same time as receiving, it will cause the LNA of the RF receiving front end or the downlink with gain The front-end of the mixer is saturated, which seriously deteriorates the receiving signal-to-noise ratio, resulting in a decrease in the recognition distance of the reader and an increase in the demodulation error rate, and a sharp decline in the performance of the entire reader

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