Classifications

• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
  • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
  • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
  • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
  • G06K19/0701—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips at least one of the integrated circuit chips comprising an arrangement for power management
  • G06K19/0707—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips at least one of the integrated circuit chips comprising an arrangement for power management the arrangement being capable of collecting energy from external energy sources, e.g. thermocouples, vibration, electromagnetic radiation
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
  • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
  • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
  • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
  • G06K19/0723—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
  • G06K7/0008—General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

Definitions

• the present invention pertains to a remote communication system, and, more particularly, to a radio frequency (RF) identification system and method that provides remote energy to an RF identification tag at a first frequency and communicates data signals to and from the tag at a second frequency.
• RF radio frequency
• Radio frequency (RF) technology which is employed in many industries.
• RF technology is in locating, identifying, and tracking objects, such as animals, inventory, and vehicles.
• RF identification (RFID) tag systems have been developed to facilitate monitoring of remote objects.
• a basic RFID system 10 consists of three components, an antenna 12, a transceiver with decoder 14, and a transponder (commonly called an RF tag) 16.
• the antenna 12 emits electromagnetic radio signals generated by the transceiver 14 to activate the tag 16.
• the tag 16 is activated, data can be read from or written to the tag.
• the antenna 12 is a component of the transceiver and decoder 14 to become an interrogator (or reader) 18, which can be configured either as a hand held or a fixed-mount device.
• the interrogator 18 emits the radio signals 20 in range from one inch to one hundred feet or more, depending upon its power output and the radio frequency used.
• an RF tag 16 passes through the electromagnetic radio waves 20, the tag 16 detects the signal 20 and is activated. Data encoded in the tag 16 is then transmitted by a modulated data signal 22 through an antenna 24 to the interrogator 18 for subsequent processing.
• RFID systems are non-contact, non-line-of-sight capability of the technology.
• Tags can be read through a variety of substances such as snow, fog, ice, paint, dirt, and other visually and environmentally challenging conditions where bar codes or other optically-read technologies would be useless.
• RF tags can also be read at remarkable speeds, in most cases responding in less than one hundred milliseconds.
• the beam-powered RFID tag is often referred to as a passive device because it derives the energy needed for its operation from the radio frequency energy beamed at it.
• the tag rectifies the field and changes the reflective characteristics of the tag itself, creating a change in reflectivity that is seen at the interrogator.
• a battery-powered semi-passive RFID tag operates in a similar fashion, modulating its RF cross section in order to reflect a delta to the interrogator to develop a communication link.
• the battery is the source of the tag's operational power.
• a transmitter is used to create its own radio frequency energy powered by the battery.
• a typical RF tag system 10 will contain at least one tag 16 and one interrogator 18.
• the range of communication for such tags varies according to the transmission power of the interrogator 18 and the tag 16.
• Battery-powered tags operating at 2,450 MHz have traditionally been limited to less than ten meters in range. However, devices with sufficient power can reach up to 200 meters in range, depending on the frequency and environmental characteristics.
• Conventional RF tag systems utilize continuous wave backscatter to communicate data from the tag 16 to the interrogator 18. More specifically, the interrogator 18 transmits a continuous-wave radio signal to the tag 16, which modulates the signal 20 using modulated backscattering wherein the electrical characteristics of the antenna 24 are altered by a modulating signal from the tag that reflects a modulated signal 22 back to the interrogator 18.
• the modulated signal 22 is encoded with information from the tag 16.
• the interrogator 18 then demodulates the modulated signal 22 and decodes the information.
• the present invention provides a remote communication system that includes a remote communication device having an antenna configured to receive a first signal and a second signal at different frequencies and to transmit a third signal; a power circuit configured to provide a supply voltage from the first signal; and an identification circuit coupled to the antenna and the power circuit and configured to use the supply voltage to generate the third signal for transmission by the antenna.
• the antenna may be configured to have a single antenna to receive first and second signals and transmit a third signal, or it may have a first antenna to receive the first signal and a second antenna to both receive the second signal and transmit the third signal.
• the first signal is at a frequency that is lower than the frequency of the second and third signals.
• the power circuit is configured to rectify the first signal into a supply voltage, such as a DC supply voltage for supplying a DC current.
• the antenna is configured to receive a first signal that is in the form of either radiated light energy, a magnetic field, or electromagnetic signals, such as radio frequency signals.
• a remote communication system in accordance with another embodiment of the invention, includes a source of radiated energy; a transceiver configured to transmit a first data signal and to receive a second data signal; and a transponder configured to receive the radiated energy and convert the radiated energy into a supply voltage that is used to receive the first data signal and to transmit the second data signal.
• the transponder is configured to transform the first data signal into the second data signal.
• a remote communication method includes receiving an energy signal and converting the energy signal into a supply voltage; receiving a first data signal at a frequency that is different than the frequency of the energy signal; and transforming the first data signal in accordance with a predetermined transformation scheme into a second data signal and transmitting the second data signal, all using the supply voltage converted from the energy signal.
• the energy signal and the first data signal are received simultaneously.
• the energy signal is converted by rectification into a DC supply voltage for generating a DC current.
• the transformation of the first data signal is preferably performed by modulating the first data signal into the second data signal in accordance with a predetermined modulation scheme.
• the disclosed embodiments of the present invention provide a passive RF tag system that extracts a greater supply voltage from a received signal to achieve a greater transmission range.
• This increase in the communication distance enables use of passive RF tags for broader applications, such as tracking and identifying inventory in large warehouses, battlefield weaponry, and animals, without increasing the size and cost of such tags.
• Figure 1 is a schematic of an existing RF tag system
• Figure 2 is a schematic of a remote communication system formed in accordance with the present invention
• FIG. 3 is a schematic of a remote communication system formed in accordance with another embodiment of the present invention.
• Figure 4 is a more detailed schematic of the tag of Figure 2;
• Figure 5 is a block diagram of the identification circuit of the tag of Figure 4;
• Figure 6 is a more detailed schematic of the power circuit of the embodiment depicted in Figure 3.
• the remote communication system 26 includes an energy source transmitter 28 configured to transmit an energy signal 30, and an interrogator 32 configured to transmit a first data signal 34 and to receive a second data signal 36. More particularly, the energy source transmitter 28 includes an antenna 38 configured to transmit the energy signal at a first frequency.
• the interrogator 32 includes an antenna 40 configured to transmit the first data signal 34 at a second frequency and to receive the second data signal 36 at either a second frequency or, if desired, at a third frequency.
• the energy source 28 and interrogator 32 can be separate components at either the same location or at different locations.
• the energy source 28 and the interrogator 32 can be formed as a single integrated unit with two antennas.
• the energy source 28 can be a parasitic source of energy, such as wall current, or radio frequency signals from outside transmitters, such as commercial radio stations, or even signals emitted by cell phones.
• a source of energy could be light energy from natural or artificial sources.
• a transponder 42 On the receiving side, a transponder 42 is provided that includes a power circuit 44 and a identification circuit 46 coupled to the power circuit.
• the power circuit 44 has an antenna 48 to receive the energy signal 30.
• the power circuit is configured to rectify the energy signal to provide a supply voltage to the identification circuit 46.
• the identification circuit 46 has its own antenna 50 to receive the first data signal 34, which is transformed within the identification circuit 46 into the second data signal 36 that is then transmitted via the same antenna 50.
• the remote communications system 52 includes an interrogator 54 having an antenna 56 configured to transmit a first data signal 58 and to receive a second data signal 60. Also shown is a transponder in the form of a tag 62 having an antenna 64 to receive the first data signal 58, which is transformed by the tag 62 into the second data signal 60 that is transmitted from the antenna 64.
• the antenna 64 is configured to also receive an energy signal 66 from an energy source 68.
• the tag 62 is configured to rectify the energy signal 66 into a supply voltage for supplying a DC current to circuitry in the tag 62.
• the energy source can be a component of the interrogator 54, or it can be a separate transmitter, as in the embodiment shown in Figure 2, or it may be an external energy source, such as a parasitic energy source, as described more fully above with respect to Figure 2.
• FIG 4 illustrates in more detail the power circuit 44 and the identification circuit 46 of the first embodiment shown in Figure 2.
• the power circuit 44 receives the energy signal 30 through the antenna 48, where it is rectified by first and second diodes 70, 72 and a resonant parallel RC circuit 74 composed of a resistor 76 and capacitor 78.
• the output of the power circuit 44 is the positive supply voltage (V+).
• This supply voltage (V+) is received by the identification circuit 46, which in this case is shown as an RFID application- specific integrated circuit (ASIC) 80.
• ASIC application- specific integrated circuit
• the details of a representative ASIC 80 are shown in Figure 5, including a power interface 82 configured to receive the supply voltage (V+). Power is distributed from the power interface 82 to a memory 84, a control circuit 86, and a modulation/demodulation circuit 88.
• the construction of these circuits is known to those skilled in the art and will not be described in detail herein.
• the antenna 64 receives the energy signal 66 and the first data signal 58.
• the antenna 64 is configured to absorb the energy signal 66 received at a first frequency and to be reflective of the first data signal 58, received at a second frequency f 2 .
• the antenna is modulated by a FET transistor 90 controlled by a data signal (data) at its control gate.
• a rectifier circuit 92 is shown therein, having a construction identical to the circuit 74 shown in Figure 4 for generating the supply voltage (V+).
• the second data signal 60 is generated by the FET transistor 90 for transmission by the antenna 64.
• the antenna could be a quarter-wave dipole antenna that provides a delta of 1/4 ⁇ f 2 for receiving the first data signal 58 and backscattering the second data signal 60.
• the system would preferably transmit the power signals at a low frequency such as 420 MHz, or at a frequency permitted by law.
• the first and second data signals would be transmitted at a higher frequency, such as 2450 MHz or 5800 MHz, again, as permitted by law.
• other frequencies may be used as known to those skilled in the art.
• the laws of certain countries, such as the FCC in the United States permit higher power transmission at higher frequencies under predefined conditions.
• the energy signal could be at a higher frequency than the data signal.
• the disclosed embodiments of the present invention thus provide enhanced supply voltage for passive RF tags to achieve greater communication distance with one or more interrogation units.
• the received energy signal may be transmitted from the interrogation units or energy may be extracted from existing sources, such as near-by radio stations, or even sunlight, thus keeping the size and cost of the RF tag to a minimum while increasing its range and its usefulness.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• General Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Artificial Intelligence (AREA)
• Computer Vision & Pattern Recognition (AREA)
• Computer Networks & Wireless Communication (AREA)
• Near-Field Transmission Systems (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)
• Transceivers (AREA)
• Mobile Radio Communication Systems (AREA)

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• 2001
  • 2001-05-31 AU AU2001275117A patent/AU2001275117A1/en not_active Abandoned
  • 2001-05-31 JP JP2002502707A patent/JP2003536302A/ja active Pending
  • 2001-05-31 EP EP01941791A patent/EP1290618A2/de not_active Withdrawn
  • 2001-05-31 WO PCT/US2001/017769 patent/WO2001095242A2/en not_active Ceased

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