RFID antenna multiplexing

摘要

A system to multiplex antennas for radio-frequency communication uses one or more antenna shorting circuits to selectively enable RF communication via one of a plurality of antenna matching networks. The system is cost-efficient compared to alternatives. The RF communication includes read and/or read/write communication with, e.g., radio-frequency identification (RFID) tags.

主权项

1. A system to multiplex antennas for radio-frequency (RF) communication, the system comprising:
a radio-frequency (RF) reader circuit configured to establish radio-frequency communication by controlling a first antenna matching network and a second antenna matching network, wherein the first antenna matching network is configured to match a first antenna to a receiver and the second antenna matching network is configured to match a second antenna to the same receiver; a first alternating-current shorting circuit configured to selectively establish electrical coupling for alternating current between the first antenna matching network and the first antenna; a second alternating-current shorting circuit configured to selectively establish electrical coupling for alternating current between the second antenna matching network and the second antenna; a controller configured to control the first and second alternating-current (AC) shorting circuits to operate selectively in one of the following states at a given time:
i) a first state wherein radio-frequency communication is established through the first antenna and electrical coupling for alternating current is shorted by the second alternating-current shorting circuit,ii) a second state wherein radio-frequency communication is established through the second antenna and electrical coupling for alternating current is shorted by the first alternating-current shorting circuit, oriii) a third state wherein electrical coupling for alternating current is shorted by the first alternating-current shorting circuit and electrical coupling for alternating current is shorted by the second alternating-current shorting circuit; and wherein the controller is further configured to cause operation of the first alternating-current shorting circuit and the second alternating-current shorting circuit in a predetermined order.