Piezo-electric tag

Abstract

A piezo-electric tag in the form of a card has a first dipole antenna, a first rectification circuit, a piezo-electric transformer, a second rectification circuit, and a transponder circuit. In operation, the antenna receives incoming radiation and generates a corresponding signal which propagates to the first circuit which demodulates and filters it to generate a signal which is applied to the transformer to excite it. The transformer increases the voltage amplitude of the signal by generating a relatively higher voltage amplitude signal which is used in the tag to generate a signal for supplying power to the transponder. The transformer provides voltage magnitude enhancement to generate potentials suitable for operating active electronic circuits incorporated into the tag. The tag can be personnel wearable and even adapted for permanent inclusion into biological systems.

1. A piezo-electric tag, comprising:
 a) receiving means for receiving input radiation and generating a corresponding received signal; 
 b) piezo-electric vibrating means for increasing voltage magnitude of the received signal to continuously generate a supply potential while the input radiation is being received; and 
 c) electronic circuit means powerable by the supply potential, wherein the electronic circuit means is continuously coupled to the piezo-electric vibrating means to receive the supply potential. 
 
     
     
       2. The tag according to  claim 1 , wherein the vibrating means comprises a piezo-electric transformer incorporating mutually vibrationally coupled primary and secondary regions, the transformer being operable to be excited into vibration by the received signal at the primary region and to generate a corresponding output signal at the secondary region for use in generating the supply potential. 
     
     
       3. A tag according to  claim 1 , wherein the vibrating means comprises a piezo-electric bi-morph operable to be excited into vibration by the received signal and to generate a corresponding output signal for use in generating the supply potential. 
     
     
       4. The tag according to  claim 1 , wherein the vibrating means comprises a silicon micromachined device comprising an array of resonant elements, each element incorporating an associated piezo-electric transducer operable to generate an element signal in response to vibration of its associated element, the transducers being connected in series to add their element signals to provide an overall output from which the supply potential is generated, and driving means operable to be driven by the received signal for stimulating the elements into vibration and thereby generating the supply potential. 
     
     
       5. The tag according to  claim 4 , wherein the resonant elements are operable at resonance to generate the supply potential. 
     
     
       6. The tag according to  claim 4 , wherein the resonant elements are housed in an evacuated environment for increasing their resonance Q factor. 
     
     
       7. The tag according to  claim 1 , wherein the receiving means incorporates demodulating means for demodulating modulation components present in the received radiation to generate the received signal. 
     
     
       8. The tag according to  claim 7 , wherein the demodulating means incorporates zero-bias Schottky diodes for demodulating the received radiation to generate the received signal. 
     
     
       9. The tag according to  claim 7 , wherein the demodulating means incorporates transistors operable as synchronous demodulators for demodulating the received radiation to generate the received signal. 
     
     
       10. The tag according to  claim 1 , wherein the circuit means is operable to function in a class C mode for reducing tag power consumption. 
     
     
       11. The tag according to  claim 1 , wherein the receiving means incorporates first and second antennas for generating the received signal for exciting the vibrating means, the first antenna being adapted to respond to microwave radiation, and the second antenna being adapted to respond to radiation having a carrier frequency corresponding to a resonant frequency of the vibrating means. 
     
     
       12. The tag according to  claim 1 , wherein the receiving means incorporates at least one of a metallic film dipole antenna, a loop antenna and a patch antenna for at least one of receiving and emitting radiation. 
     
     
       13. The tag according to  claim 1 , wherein the circuit means comprises responding means for emitting output radiation from the tag, the responding means being powerable by the supply potential. 
     
     
       14. The tag according to  claim 13 , wherein the vibrating means is operable to recover a clock component of Manchester bi-phase encoded radiation received at the tag, and wherein the responding means is operable to use the clock component to demodulate the encoded radiation to generate corresponding demodulated data for use in the tag. 
     
     
       15. The tag according to  claim 13 , wherein the tag incorporates two antennas, one antenna for use in generating the received signal, and the other antenna incorporated into the responding means for at least one of emitting and receiving radiation. 
     
     
       16. The tag according to  claim 13 , wherein the antennas are conductive metallic film dipole antennas. 
     
     
       17. The tag according to  claim 1 , the tag having a form of a block. 
     
     
       18. The tag according to  claim 1 , the tag having a form of a planar card. 
     
     
       19. The tag according to  claim 18 , wherein the card incorporates recesses for accommodating the receiving means, the vibrating means and the responding means. 
     
     
       20. The tag according to  claim 13 , wherein the responding means is a transponder operable to receive input radiation to the tag and emit output radiation in response from the tag. 
     
     
       21. The tag according to  claim 20 , wherein the transponder is operable to modulate the output radiation with a signature code by which the tag is individually identified. 
     
     
       22. The tag according to  claim 20 , wherein the transponder incorporates a reflection amplifier for amplifying the input radiation to generate the output radiation. 
     
     
       23. The tag according to  claim 20 , wherein the transponder is operable in a pseudo-continuous mode and incorporates a delay line for delaying the output radiation relative to the input radiation, thereby counteracting spontaneous oscillation from arising within the transponder from feedback therein. 
     
     
       24. The tag according to  claim 1 , and a metallic earthing plane for providing a common signal earth for the tag. 
     
     
       25. The tag according to  claim 1 , and means for implantation into a biological system and operable for at least one of monitoring and stimulating the biological system. 
     
     
       26. A wireless communication device, comprising:
 a receiver circuit configured to receive input radiation and to generate, from the input radiation, a signal having a voltage magnitude; and   a piezo-electric transformer configured to increase the voltage magnitude of the signal to continuously generate a power supply signal capable of powering an electronic circuit while the input radiation is being received, wherein the piezo-electric transformer is continuously coupled to the electronic circuit that is powered by the power supply signal.   
     
     
       27. The wireless communication device according to claim 26, wherein the receiver circuit includes an antenna arrangement configured to receive electromagnetic radiation and generate the signal therefrom, and wherein the electronic circuit includes a transponder that is operable using the power supply signal to generate an output signal that is transmitted by the antenna arrangement.  
     
     
       28. The wireless communication device according to claim 27, wherein the transponder is an oscillator configured to generate and transmit through the antenna arrangement the output signal in the form of encoded radiation that identifies the wireless communication device.  
     
     
       29. The wireless communication device according to claim 28, wherein the encoded radiation is unique to the oscillator.  
     
     
       30. The wireless communication device according to claim 27, wherein the transponder is operable to switch cyclically between a first period and a second period, the transponder generating the output signal during the first period and not generating the output signal during the second period.  
     
     
       31. The wireless communication device according to claim 27, wherein the transponder includes a pulsed transmitter in communication with the antenna arrangement, the pulsed transmitter generating the output signal in the form of bursts of signal that are emitted as radiation from the antenna arrangement.  
     
     
       32. The wireless communication device according to claim 31, wherein the bursts of signal are repeated at a rate that is unique to the wireless communication device.  
     
     
       33. The wireless communication device according to claim 27, wherein the transponder is configured to generate and transmit the output signal only when the power supply signal exceeds a threshold.  
     
     
       34. The wireless communication device according to claim 33, wherein the transponder is configured to prevent electrical flow of the power supply signal when the power supply signal is less than the threshold.  
     
     
       35. The wireless communication device according to claim 34, wherein the transponder includes a transistor configured to conduct the power supply signal for only part of a signal cycle when the power supply signal exceeds the threshold.  
     
     
       36. The wireless communication device according to claim 27, wherein the antenna arrangement includes a loop antenna coupled to the piezo-electric transformer, the loop antenna having an inductance that, in combination with a capacitance of the transformer, electrically resonates at an input radiation frequency corresponding with a vibrational mode of the transformer.  
     
     
       37. The wireless communication device according to claim 27, wherein the antenna arrangement is comprised of a single antenna, the device further comprising a rectifier circuit coupled to the antenna for generating the input signal, the transponder having a transmitter with a first transmitter output coupled to the output of the rectifier circuit and a second transmitter output coupled to the antenna, wherein during transmission of the output signal, the transmitter is configured to deliver a signal via the first transmitter output to reverse bias the rectifier circuit and then deliver the output signal via the second transmitter output to the antenna.  
     
     
       38. The wireless communication device according to claim 37, wherein the power supply signal generated by the piezo-electric transformer is demodulated by a demodulator circuit and provided to the transmitter.  
     
     
       39. The wireless communication device according to claim 37, wherein the wireless communication device has a major surface and the antenna is sized to occupy a majority of the major surface of the device.  
     
     
       40. The wireless communication device according to claim 37, wherein the output signal delivered from the transmitter to the antenna is comprised of bursts of signal.  
     
     
       41. The wireless communication device according to claim 26, wherein the piezo-electric transformer is comprised of a ceramic bi-morph in the form of an elongate member supported at one end and free for vibration at an another end.  
     
     
       42. The wireless communication device according to claim 26, wherein the piezo-electric transformer is comprised of an array of one or more suspended silicon cantilevers, each cantilever incorporating a deposited film piezo-electric transducer operable to generate a signal in response to vibration of the cantilever, wherein the transducers are connected in series to add their signal voltages to provide the power supply signal.  
     
     
       43. The wireless communication device according to claim 42, further comprising an excitation transducer operable to be driven by a drive signal derived from the electromagnetic radiation received by the antenna arrangement for mechanically exciting the one or more cantilevers into vibration.  
     
     
       44. The wireless communication device according to claim 43, wherein the vibration is at a resonant frequency of the one or more cantilevers.  
     
     
       45. The wireless communication device according to claim 26, wherein the device is configured to attach to an item of merchandise and is operable in association with an interrogating source to provide a merchandise anti-theft system.  
     
     
       46. The wireless communication device according to claim 26, wherein the device is configured to attach to a person and provide a wearable identification device.  
     
     
       47. The wireless communication device according to claim 26, wherein the device is configured to attach to a person and provide a wearable data logger, wherein the wireless communication device further comprises a sensor and a memory coupled to the sensor for recording data sensed by the sensor.  
     
     
       48. The wireless communication device according to claim 47, wherein the electronic circuit includes a transponder that is configured to modulate an output signal to transmit data sensed by the sensor in response to received radiation.  
     
     
       49. The wireless communication device according to claim 48, wherein the sensor is an environmental sensor and the data logger is usable to monitor safety of an environment of a person wearing the data logger.  
     
     
       50. The wireless communication device according to claim 26 arranged in a system that further comprises an interrogator configured to emit the radiation received by the receiver circuit and receive an output signal transmitted by the wireless communication device.  
     
     
       51. The wireless communication device according to claim 26, wherein the receiver circuit incorporates first and second antennas for generating the signal having a voltage magnitude, the first antenna being adapted to respond to microwave radiation and the second antenna being adapted to respond to radiation having a carrier frequency corresponding to a resonant frequency of the piezo-electric transformer.  
     
     
       52. The wireless communication device according to claim 26, wherein the piezo-electric transformer comprises a silicon micromachined device having an array of resonant elements, each element incorporating an associated piezo-electric transducer operable to generate an element signal in response to vibration of its associated element, the transducers being connected in series to add their element signals to provide the output signal, and a driver operable to be driven by the input signal to stimulate the elements into vibration and thereby generate the power supply signal.  
     
     
       53. A method of wireless communication, comprising:
 generating an interrogating signal in the form of electromagnetic radiation;   transmitting the interrogating signal to a wireless communication device that includes a receiver circuit, a piezo-electric transformer, and a transponder that is continuously coupled to the piezo-electric transformer, wherein the receiver circuit is configured to receive the radiation and generate a signal therefrom, wherein the piezo-electric transformer is configured to increase an electrical magnitude of the generated signal to continuously generate a power supply signal capable of powering the transponder while the radiation is being received, and wherein the transponder is operable to transmit an output signal;   receiving an output signal transmitted by the wireless communication device; and   processing the received output signal.   
     
     
       54. The method according to claim 53, wherein the piezo-electric transformer is comprised of an array of resonant elements connected in series, the method further comprising:
 using the interrogating signal to vibrate a resonant element, wherein the vibrating resonant element produces a first output signal that causes the next resonant element in the series to vibrate and produce a second output signal having an electrical magnitude greater than the first output signal; and   generating the power supply signal from the output signal of the last resonant element in the series.    
     
     
       55. The method according to claim 53, further comprising:
 distributing a plurality of the wireless communication devices along a path to a destination;   providing a vehicle with a direction sensitive interrogating source capable of generating the interrogating signal received by the receiver circuit of a wireless communication device;   interrogating the wireless communication devices from a source by emitting interrogating radiation to the wireless communication devices and receiving radiation therefrom, wherein the received radiation indicates a direction of the devices relative to the source;   determining a direction of the wireless communication devices relative to the source and hence determining the path;   moving the vehicle along the path; and   repeating the interrogating, determining, and moving the vehicle until the vehicle reaches the destination.    
     
     
       56. The method according to claim 53, further comprising attaching the wireless communication device to an item of merchandise and operating an interrogating source in association with the wireless communication device to provide a merchandise anti-theft system.  
     
     
       57. The method according to claim 53, further comprising attaching the wireless communication device to a person to provide a wearable identification device.  
     
     
       58. The method according to claim 53, further comprising attaching the wireless communication device to a person to provide a wearable data logger, wherein the method further comprises sensing environmental data with a sensor in the wireless communication device and recording the data sensed by the sensor in a memory coupled to the sensor.  
     
     
       59. The method according to claim 58, further comprising, in response to received radiation, modulating the output signal to transmit data sensed by the sensor.  
     
     
       60. The method according to claim 58, wherein the sensor is an environmental sensor, the method further comprising using the data logger to monitor safety of an environment of a person wearing the data logger.  
     
     
       61. The method according to claim 53, further comprising:
 placing a plurality of the wireless communication devices at points along a lane;   emitting radiation from a vehicle to power the wireless communication devices and cause the devices to emit output signals;   receiving the output signal transmitted by the wireless communication devices; and   adjusting a direction of movement of the vehicle according to the received output signal.    
     
     
       62. A piezo-electric tag, comprising:
 a receiver circuit configured to receive input radiation and generate a corresponding received signal;   a piezo-electric device configured to increase a voltage magnitude of the received signal to continuously generate a supply potential while the input radiation is being received; and   an electronic circuit powerable by the supply potential, wherein the electronic circuit is continuously coupled to the piezo-electric device to receive the supply potential.   
     
     
       63. The tag according to claim 62, wherein the piezo-electric device comprises a piezo-electric transformer incorporating mutually vibrationally coupled primary and secondary regions, the transformer being operable to be excited into vibration by the received signal at the primary region and to generate a corresponding output signal at the secondary region for use in generating the supply potential.  
     
     
       64. A tag according to claim 62, wherein the piezo-electric device comprises a piezo-electric bi-morph operable to be excited into vibration by the received signal and to generate a corresponding output signal for use in generating the supply potential.  
     
     
       65. The tag according to claim 62, wherein the piezo-electric device comprises a silicon micromachined device comprising an array of resonant elements, each element incorporating an associated piezo-electric transducer operable to generate an element signal in response to vibration of its associated element, the transducers being connected in series to add their element signals to provide an overall output from which the supply potential is generated, and a driver operable to be driven by the received signal for stimulating the elements into vibration and thereby generating the supply potential.  
     
     
       66. The tag according to claim 65, wherein the resonant elements are operable at resonance to generate the supply potential.  
     
     
       67. The tag according to claim 65, wherein the resonant elements are housed in an evacuated environment for increasing their resonance Q factor.  
     
     
       68. The tag according to claim 62, wherein the receiver circuit incorporates a demodulator for demodulating modulation components present in the received radiation to generate the received signal.  
     
     
       69. The tag according to claim 68, wherein the demodulator incorporates zero-bias Schottky diodes for demodulating the received radiation to generate the received signal.  
     
     
       70. The tag according to claim 68, wherein the demodulator incorporates transistors operable as synchronous demodulators for demodulating the received radiation to generate the received signal.  
     
     
       71. The tag according to claim 62, wherein the electronic circuit is operable to function in a class C mode for reducing tag power consumption.  
     
     
       72. The tag according to claim 62, wherein the receiver circuit incorporates first and second antennas for generating the received signal for exciting the vibrating means, the first antenna being adapted to respond to microwave radiation, and the second antenna being adapted to respond to radiation having a carrier frequency corresponding to a resonant frequency of the vibrating means.  
     
     
       73. The tag according to claim 62, wherein the receiver circuit incorporates at least one of a metallic film dipole antenna, a loop antenna and a patch antenna for at least one of receiving and emitting radiation.  
     
     
       74. The tag according to claim 62, wherein the electronic circuit comprises a transponder configured to emit output radiation from the tag, and wherein the supply potential that is continuously generated by the piezo-electric device is sufficient for the transponder to emit the output radiation. 
     
     
       75. The tag according to claim 74, wherein the piezo-electric device is operable to recover a clock component of Manchester bi-phase encoded radiation received at the tag, and wherein the transponder is operable to use the clock component to demodulate the encoded radiation to generate corresponding demodulated data for use in the tag.  
     
     
       76. The tag according to claim 74, wherein the tag incorporates two antennas, one antenna for use in generating the received signal, and the other antenna incorporated into the transponder for at least one of emitting and receiving radiation.  
     
     
       77. The tag according to claim 76, wherein the antennas are conductive metallic film dipole antennas.  
     
     
       78. The tag according to claim 62, the tag having a form of a block.  
     
     
       79. The tag according to claim 62, the tag having a form of a planar card.  
     
     
       80. The tag according to claim 79, wherein the card incorporates recesses for accommodating the receiver circuit, the piezo-electric device and the electronic circuit.  
     
     
       81. The tag according to claim 74, wherein the transponder is operable to receive input radiation to the tag and emit output radiation in response from the tag.  
     
     
       82. The tag according to claim 81, wherein the transponder is operable to modulate the output radiation with a signature code by which the tag is individually identified.  
     
     
       83. The tag according to claim 81, wherein the transponder incorporates a reflection amplifier for amplifying the input radiation to generate the output radiation.  
     
     
       84. The tag according to claim 81, wherein the transponder is operable in a pseudo-continuous mode and incorporates a delay line for delaying the output radiation relative to the input radiation, thereby counteracting spontaneous oscillation from arising within the transponder from feedback therein.  
     
     
       85. The tag according to claim 62, further comprising a metallic earthing plane for providing a common signal earth for the tag.  
     
     
       86. The tag according to claim 62, wherein the tag is configured for implantation into a biological system and is operable for at least one of monitoring and stimulating the biological system.  
     
     
       87. A wireless communication device, comprising:
 a receiver circuit configured to receive input radiation and to generate a corresponding received signal; and   a piezo-electric transformer coupled to the receiver circuit, wherein the piezo-electric transformer is configured to increase a voltage magnitude of the received signal to generate a supply potential capable of powering an electronic circuit;   wherein the receiver circuit includes first and second antennas configured to generate the received signal, and wherein the first antenna is configured to respond to microwave radiation and the second antenna is configured to respond to radiation having a carrier frequency corresponding to a resonant frequency of the piezo-electric transformer.   
     
     
       88. The wireless communication device according to claim 87, wherein the piezo-electric transformer comprises primary and secondary regions that are mutually vibrationally coupled, wherein the primary region is configured to be excited into vibration by the received signal and the secondary region is configured to generate a corresponding output signal for generating the supply potential. 
     
     
       89. The wireless communication device according to claim 87, wherein the first antenna is coupled to a rectifier circuit having an output that is coupled to the primary region of the piezo-electric transformer, and wherein the second antenna is coupled to the primary region of the piezo-electric transformer.  
     
     
       90. The wireless communication device according to claim 88, wherein the second antenna is a coil antenna configured to resonate in conjunction with electrical capacitance of the piezo-electric transformer at the resonant frequency of the piezo-electric transformer. 
     
     
       91. A wireless communication device according to claim 87, wherein the piezo-electric transformer comprises a piezo-electric bi-morph configured to be excited into vibration by the received signal and to generate a corresponding output signal for generating the supply potential. 
     
     
       92. A wireless communication device according to claim 87, wherein the piezo-electric transformer comprises a silicon micromachined device that includes:
 an array of one or more resonant elements, wherein each resonant element comprises an associated piezo-electric transducer configured to generate an element signal in response to vibration of the resonant element, and wherein the piezo-electric transducers of the one or more resonant elements are connected in series such that their element signals combine to provide an overall output from which the supply potential is generated; and   an excitation transducer configured to be driven by the received signal to stimulate the one or more resonant elements into vibration and thereby generate the supply potential.   
     
     
       93. A wireless communication device according to claim 87, wherein the electronic circuit comprises a transponder powerable by the supply potential and configured to emit output radiation.