Rf Switched Rfid Multiplexer

• US 20090009296A1
• Filed: 02/15/2006
• Published: 01/08/2009
• Est. Priority Date: 02/15/2006
• Status: Active Grant

• Current Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Original Assignee: Sensormatic Electronics Corporation (Johnson Controls International plc)
• Inventors: Shafer, Gary Mark
• Granted Patent: US 8,941,471 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas

Abstract

A radiofrequency identification (RFID) multiplexer, which may be in a network, interprets an RF signal from an RFED reader as RFE) tag interrogation data. A single cable directs an RF signal from the RFID reader and RF control signals and/or RF power through the multiplexer. An RF sampler may be coupled to the cable; and an RF detector detects the RF signal from the cable via the RF sampler. A data decoder decodes and interprets the RF signal as the RFID tag interrogation data and forwards the RFID tag interrogation data to a control logic circuit as a MUX channel-change command. The logic circuit and decoder may be combined in a microcontroller, and an RF backscatter modulator coupled to the cable enables reverse communication with the RFID reader to determine whether another RFID multiplexer is coupled to the RFID multiplexer.

Claims

1. A radiofrequency identification (RFID) multiplexer (MUX) configured to interpret an RF signal from an RFID reader as RFID tag interrogation data.

2. The RFID multiplexer according to claim 1, further comprising:

a cable enabling the RF signal to be provided from the RFID reader;

an RF sampler operatively coupled to the cable; and

an RF detector operatively coupled to the RF sampler, the RF detector detecting the RF signal from the cable via the RF sampler.

3. The RFID multiplexer according to claim 2, further comprising:

a data decoder operatively coupled to the RF detector; and

a control logic circuit operatively coupled to the data decoder,

wherein the data decoder decodes and interprets the RF signal detected by the RF detector as the RFID tag interrogation data.

4. The RFID multiplexer according to claim 3, wherein the data decoder forwards the RFID tag interrogation data to the control logic circuit as a MUX channel-change command.

5. The RFID multiplexer according to claim 5, wherein the control logic circuit and data decoder are combined in a microcontroller, and the RFID multiplexer further comprises:

an RF backscatter modulator operatively coupled to the microcontroller and to the RF sampler,

the RF backscatter modulator being coupled to the cable to enable reverse communication with the RFID reader.

6. The RFID multiplexer according to claim 5, wherein the RF backscatter modulator enables the RFID reader to determine whether another RFID multiplexer is coupled to the RFID multiplexer.

7. A radiofrequency identification (RFID) multiplexer configured to be coupled to an RFID reader wherein a single cable directs an RF signal from the RFID reader and at least one of RF control signals and RF power through the RFID multiplexer.

8. The RF multiplexer according to claim 7, wherein the multiplexer is configured to be coupled to the RFID reader via the single cable, and the RFID multiplexer further comprises:

a plurality of RF output switches configured to provide a plurality of output channels,

wherein the single cable directs the RF signal and at least one of RF control signals and RF power from the RFID reader through the output channels.

9. The RFID multiplexer according to claim 7, wherein the single cable directs at least RF signal and RF power, and wherein the RF power is recovered from the RF signal via a power recovery circuit.

10. The RFID multiplexer according to claim 9,

wherein the power recovery circuit includes one of (a) an RF choke operatively coupled to the cable which recovers one of direct current (DC) voltage and alternating current (AC) voltage from the RF signal to direct the RF power through the multiplexer, and (b) an RF sampler operatively coupled to the cable and an RF detector operatively coupled to the RF sampler, wherein the RF sampler and the RF detector recover one of direct current (DC) voltage and alternating current (AC) voltage from the RF signal to direct the RF power through the multiplexer.

11. The RFID multiplexer according to claim 7, wherein the RFID multiplexer is configured to be coupled to the RFID reader to receive and to transmit the RF signal via an RF signal input antenna coupled to the single cable and an RFID reader antenna coupled to the RFID reader.

12. A radiofrequency identification (RFID) network comprising:

an RFID multiplexer (MUX); and

an RFID reader operatively coupled to the RFID multiplexer, wherein the RFID multiplexer is configured to interpret an RF signal from the RFID reader as RFID tag interrogation data.

13. The RFID network according to claim 12, further comprising:

a cable enabling the RF signal to be provided from the RFID reader;

an RF sampler operatively coupled to the cable; and

an RF detector operatively coupled to the RF sampler, the RF detector detecting the RF signal from the cable via the RF sampler.

14. The RFID network according to claim 13, further comprising:

a data decoder operatively coupled to the RF detector; and

a control logic circuit operatively coupled to the data decoder,

wherein the data decoder decodes and interprets the RF signal detected by the RF detector as the RFID tag interrogation data.

15. The RFID network according to claim 14, wherein the data decoder forwards the RFID tag interrogation data to the control logic circuit as a MUX channel-change command.

16. The RFID network according to claim 14, wherein the control logic circuit and data decoder are combined in a microcontroller, and the RFID multiplexer further comprises:

an RF backscatter modulator operatively coupled to the microcontroller and to the RF sampler,

the RF backscatter modulator being operatively coupled to the cable to enable reverse communication with the RFID reader.

17. The RFID network according to claim 16, wherein the RF backscatter modulator enables the RFID reader to determine whether another RFID multiplexer is coupled to the RFID multiplexer.

18. A radiofrequency identification (RFID) network comprising:

an RFID reader; and

an RFID multiplexer operatively coupled to the RFID reader wherein a single cable directs an RF signal from the RFID reader and at least one of RF control signals and RF power through the RFID multiplexer.

19. The RFID network according to claim 18, wherein the multiplexer is configured to be coupled to the RFID reader via the single cable, and the RFID multiplexer further comprises:

a plurality of RF output switches configured to provide a plurality of output channels,

wherein the single cable directs the RF signal and at least one of RF control signals and RF power from the RFID reader through the output channels.

20. The RFID network according to claim 18, wherein the single cable directs at least RF signal and RF power, and wherein the RF power is recovered from the RF signal via a power recovery circuit.

21. The RFID network according to claim 20,

wherein the power recovery circuit includes one of (a) an RF choke operatively coupled to the cable which recovers one of direct current (DC) voltage and alternating current (AC) voltage from the RF signal to direct the RF power through the multiplexer, and (b) an RF sampler operatively coupled to the cable and an RF detector operatively coupled to the RF sampler, wherein the RF sampler and the RF detector recover one of direct current (DC) voltage and alternating current (AC) voltage from the RF signal to direct the RF power through the multiplexer.

22. The RFID network according to claim 18, wherein the RFID multiplexer is operatively coupled to the RFID reader to receive and to transmit the RF signal via an RF signal input antenna operatively coupled to the single cable and an RFID reader antenna operatively coupled to the RFID reader.