SYSTEMS AND METHODS TO USE RADAR IN RFID SYSTEMS

• US 20160363662A1
• Filed: 08/07/2014
• Published: 12/15/2016
• Est. Priority Date: 06/05/2008
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Tuttle, John R.
• Granted Patent: US 10,571,558 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 13/282 using a frequency modulated carrier wave G01S13/286 takes precedence
• CPC Class Codes: G01S 13/582 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 2013/9316 combined with communication equipment with other vehicles or with base stations
• CPC Class Codes: G01S 2013/9329 cooperating with reflectors or transponders

Abstract

Systems and methods to use radar systems for radio frequency identification (RFID) applications. In one embodiment, radar systems are adapted to use RFID communications protocols and methods to enhance the usefulness of radar systems beyond the determination of the presence, distance, direction and/or speed of a vehicle or object, to additionally include the transmission of data such as object identification and additional messages or data.

Claims

1. A radio frequency identification (RFID) tag, comprising:

an antenna;

a transceiver coupled to the antenna to

receive radar pulses configured to allow a radar system to determine at least one of distance, direction and speed of objects, and

modulate reflection of the radar pulses; and

a controller coupled to the transceiver to modulate data stored in the RFID tag across a plurality of separate radar pulses.

2. The RFID tag of claim 1, wherein a predetermined number of bits of the data is modulated on each of the plurality of separate radar pulses.

3. The RFID tag of claim 1, wherein each of the plurality of separate radar pulses is modulated to transmit one bit of the data.

4. The RFID tag of claim 1, wherein the controller determines a pulse repetition frequency of signals of the radar system to modulate the data.

5. A radio frequency identification (RFID) system, comprising:

an RFID tag; and

a radar system including

a radar transmitter,

a radar receiver, and

an RFID reader circuit, wherein

the radar receiver receives a pulse of radio frequency electromagnetic wave transmitted by the radar transmitter and reflected by the RFID tag,

the RFID reader circuit determines, from the pulse of radio frequency electromagnetic wave received by the radar receiver, data transmitted by the RFID, and

the radar system determines at least one of distance, direction and speed of objects based on pulses of radio frequency electromagnetic wave transmitted by the radar transmitter and received by the radar receiver.

6. The RFID system of claim 5, wherein the RFID tag modulates the radio frequency electromagnetic wave according to a predetermined characteristic of electromagnetic waves transmitted by the radar transmitter.

7. The RFID system of claim 6, wherein the characteristic includes a pulse repetition frequency.

8. The RFID system of claim 5, wherein the radar system determines a position of the RFID tag based on a round trip time of the radio frequency electromagnetic wave.

9. The RFID system of claim 5, wherein the radar system determines a speed of the RFID tag based on a Doppler frequency shift in the radio frequency electromagnetic wave reflected by the RFID tag.

10. The RFID system of claim 5, wherein the radar transmitter transmits the radio frequency electromagnetic wave in a first mode to allow the RFID reader circuit to determine the data;

and the radar transmitter is to transmit in a second mode to determine a range of the RFID tag.

11. A radio frequency identification (RFID) reader, comprising:

a transmitter configured to transmit pulses of radio frequency electromagnetic wave;

a receiver configured to receive the pulses of radio frequency electromagnetic wave reflected by an object;

a radar circuit configured to determine at least a distance, a direction or a speed of the object based on pulses of radio frequency electromagnetic wave reflected by the object and received in the receiver; and

a reader circuit configured to determine data modulated on the pulses of radio frequency electromagnetic wave reflected by the object and received in the receiver.

12. The RFID reader of claim 11, further comprising:

a duplexer configured to

couple the radar circuit to the transmitter and the receiver in a first mode, and

couple the RFID reader circuit to the transmitter and the receiver in a second mode.

13. The RFID reader of claim 12, wherein the reader circuit controls the transmitter to modulate data on a radio frequency electromagnetic wave transmitted by the transmitter.

14. The RFID reader of claim 11, wherein the receiver has a matched filter configured to receive an input signal generated according to the pulses of radio frequency electromagnetic wave reflected by the object and received in the receiver;

and a pulse width of an output of the matched filter is smaller than a pulse width of the input.

15. A method, comprising:

transmitting an electromagnetic wave from a radar transmitter toward an object having an RFID tag, the electromagnetic wave including a pulse of electromagnetic wave configured to allow a radar system to monitor at least one of distance, direction and speed of objects, wherein the RFID tag modulates reflection of the electromagnetic wave based on data stored in the RFID tag;

receiving, in a radar receiver of the radar systema, the electromagnetic wave reflected by the RFID tag;

determining, by the radar system, at least a distance, a direction, or a speed of the object; and

extracting, via a reader circuit, the data modulated on the electromagnetic wave reflected by the RFID tag and received in the radar receiver.

16. The method of claim 15, wherein the RFID tag modulates the data on a plurality of separate pulses transmitted from the radar transmitter.

17. The method of claim 16, wherein the pulse of electromagnetic wave is modulated to achieve pulse compression in detecting the reflected electromagnetic wave.

18. The method of claim 15, further comprising:

modulating an electromagnetic wave to represent a command to the RFID tag; and

transmitting the electromagnetic wave modulated with the command from the radar transmitter to the RFID tag;

wherein the modulating of the electromagnetic wave reflected using the RFID tag according to the data stored in the RFID tag is in response to the command.

19. The method of claim 15, wherein the radar transmitter continuously transmitting the electromagnetic wave while the radar receiver receives reflected the electromagnetic wave;

and the method further comprises;

comparing the electromagnetic wave transmitted by the radar transmitter and the reflected electromagnetic wave received by the radar receiver to determine a round trip time of the reflected electromagnetic wave.

20. The method of claim 15, further comprising:

transmitting a separate electromagnetic wave from the radar transmitter toward the object;

receiving the separate electromagnetic wave reflected from the object using the radar receiver; and

determining a range to the object or a rate of changing range to the object based on the separate electromagnetic wave reflected from the object and received using the radar receiver.