Method of communications in a backscatter system, interrogator, and backscatter communications system

• US 6,229,987 B1
• Filed: 04/26/2000
• Issued: 05/08/2001
• Est. Priority Date: 05/18/1998
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Ovard, David K., Greeff, Roy
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): WASHINGTON, ERIKA ALISE
• Application Number:
  US09/559,908
• Time in Patent Office: 377 Days
• Field of Search: 455/38.2, 455/101, 455/106, 340/825.54, 340/505
• US Class Current: 340/10.1
• 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

Abstract

An interrogator for use in a backscatter system, the interrogator comprising an antenna configured to receive a backscatter signal; an IQ downconverter coupled to the antenna and configured to downconvert the backscatter signal to produce I and Q signals; a combiner coupled to the IQ downconverter and configured to combine the I and Q signals to produce a combined signal; and an analog to digital converter coupled to the combiner and configured to convert the combined signal to a digital signal. A method of communications in a backscatter system, the method comprising receiving a backscatter signal; downconverting the backscatter signal with an IQ downconverter to produce I and Q signals; combining the I and Q signals to produce a combined signal; and converting the combined signal to a digital signal.

Claims

1. A backscatter receiver comprising:

an IQ downconverter configured to convert a received backscatter signal to produce I and Q signals;

a combiner coupled to the IQ downconverter and configured to combine the I and Q signals to produce a combined signal; and

an analog to digital converter coupled to the combiner and configured to convert the combined signal to a digital signal.

2. A backscatter receiver in accordance with claim 1 and further comprising automatic gain control circuitry coupled between the combiner and the analog to digital converter.

3. A backscatter receiver in accordance with claim 1 wherein the combiner is a quadrature combiner.

4. A backscatter receiver in accordance with claim 1 and further comprising an amplifier coupled between the combiner and the analog to digital converter.

5. A backscatter receiver in accordance with claim 1 and further comprising an amplifier coupled to the combiner and configured to amplify the combined signal to produce an amplified signal, and a voltage controlled amplifier coupled to the first mentioned amplifier and configured to further amplify the amplified signal.

6. A backscatter receiver comprising:

an antenna;

an IQ downconverter coupled to the antenna and configured to downconvert a backscatter signal received by the antenna to produce I is and Q signals;

a combiner coupled to the IQ downconverter and configured to combine the I and Q signals to produce a combined signal; and

an analog to digital converter coupled to the combiner and configured to convert the combined signal to a digital signal.

7. A backscatter receiver in accordance with claim 6 wherein the combiner is a quadrature combiner.

8. A backscatter receiver in accordance with claim 6 wherein the combiner is an analog combiner.

9. A backscatter receiver in accordance with claim 6 and further comprising an amplifier coupled between the combiner and the analog to digital converter, the amplifier being configured to amplify the combined signal.

10. A backscatter receiver comprising:

an antenna;

a quadrature downconverter coupled to the antenna and configured to convert a backscatter signal received by the antenna to produce I and Q signals;

a combiner coupled directly to the downconverter and configured to combine the I and Q signals to produce a combined signal; and

automatic gain control circuitry coupled to the combiner and configured to amplify the combined signal.

11. A backscatter receiver in accordance with claim 10 wherein the combiner is an analog quadrature combiner.

12. A backscatter receiver in accordance with claim 10 and further comprising an amplifier coupled to the combiner and configured to amplify the combined signal.

13. A backscatter receiver comprising:

an antenna;

a quadrature downconverter coupled to the antenna and configured to convert a backscatter signal received by the antenna to produce I and Q signals;

a combiner coupled directly to the downconverter and configured to combine the I and Q signals to produce a combined signal; and

an amplifier coupled to the combiner and configured to amplify the combined signal to produce an amplified signal, and a voltage controlled amplifier coupled to the first mentioned amplifier and configured to further amplify the amplified signal.

14. A system comprising:

a wireless communications device including an integrated circuit having a processor, and a memory, a receiver, and a backscatter modulator coupled to the processor; and

a transponder including a transmitter configured to send a transmission to the wireless communications device and subsequently transmit a continuous wave to the wireless communications device for modulation by the backscatter modulator, the transponder further including a receiver including an IQ downconverter configured to downconvert a modulated backscatter signal received from the wireless communications device into I and Q signals, a combiner coupled to the IQ downconverter and configured to combine the I and Q signals to produce a combined signal, and an analog to digital converter coupled to the combiner and configured to convert the combined signal to a digital signal.

15. A system in accordance with claim 14 wherein the transmitter is configured to send the transmission at a microwave frequency.

16. A system in accordance with claim 15 wherein the transmitter is configured to transmit the continuous wave at a microwave frequency.

17. A system in accordance with claim 14 wherein the wireless communications device includes a self contained power source coupled to the integrated circuit.

18. A system in accordance with claim 14 wherein the wireless communications device includes a battery coupled to the integrated circuit.

19. A system comprising:

a wireless communications device including an integrated circuit having a processor, and a memory, a receiver, and a backscatter modulator coupled to the processor; and

a transponder including a transmitter configured to send a transmission to the wireless communications device and subsequently transmit a continuous wave to the wireless communications device for modulation by the backscatter modulator, the transponder further including a receiver including an IQ downconverter configured to receive a modulated backscatter signal received from the wireless communications device and to produce I and Q signals, the transponder further including a combiner coupled directly to the IQ downconverter and configured to produce a combined signal, and the interrogator further including an analog to digital converter coupled to the combiner and configured to convert the combined signal to a digital signal.

20. A system in accordance with claim 19 wherein the transmitter is configured to transmit an amplitude modulated signal.