WO2014148719A1

WO2014148719A1 - Active spin rfid tag

Info

Publication number: WO2014148719A1
Application number: PCT/KR2013/009850
Authority: WO
Inventors: 오인열; 박철순; 신민철; 박승영; 민병철; 한석희
Original assignee: 한국과학기술원; 한국기초과학지원연구원; 한국과학기술연구원
Priority date: 2013-03-22
Filing date: 2013-11-01
Publication date: 2014-09-25
Also published as: KR101402784B1

Abstract

The present invention provides an active RFID tag using a spin oscillator of extremely low power consumption with no additional battery mounted, characterized by including: an energy harvesting means for harvesting surrounding energy; at least one spin oscillator without an additional storage battery provided with the power generated from the harvesting means for generating an oscillation signal of a given frequency; and a spin modulator for modulating RFID data so as to output an RF signal by means of the oscillation signal outputted from the spin oscillator.

Description

Active Spin RFID Tag

The present invention relates to an active spin radio frequency identificatcion (RFID) technology, and more particularly, by manufacturing an active RFID tag using an ultra low power spin oscillator, a small amount of power produced by energy harvesting can be utilized. The present invention relates to an active RFID tag that is small, portable, and can be attached to any object.

RFID (radio frequency identification) technology can read / write data wirelessly, eliminating the need for direct contact or scanning, simultaneously recognizing multiple data, and recognizing data in any direction. There are many advantages that are semipermanent.

Recently, due to the standardization of RFID, the decrease of the unit price, and the increase of the reading distance, the use in the industry is gradually increasing. The RFID system consists of a tag consisting of an antenna and an integrated circuit and an RFID reader. Passive RFID tags are wirelessly powered by a reader and activated. The activated RFID tag waits for a command from the reader and sends a response back to the reader when the correct command is received. If the reader sends a command and there is no response from the RFID tag after the delay specified by the standard, no further communication is made. Passive RFID systems powered by a reader have a high error rate and a short recognition distance of a transmission / reception signal.

Accordingly, the necessity of an active RFID system equipped with a power supply unit is highlighted, but there is still a problem about maintenance or environmental pollution generated from batteries used as a power source in the active RFID system.

1 is a block diagram of an active contactless identification device shown in Korean Patent Laid-Open Publication No. 2004-0040846 (November 08, 2002), which includes an antenna 210, an analog signal processor 220, and a digital signal processor 230. , A logic operation unit 240 and a power supply unit 250 for supplying power to the respective components. Since the active contactless identification device is independently provided with a power supply unit 250 composed of a battery or a storage battery, the active contactless identification device can operate even without receiving power from a reader such as a passive type. In order to operate the respective circuits, the battery or the battery constituting the power supply unit 250 needs to be periodically charged, which consumes a lot of time for charging, and thus the operation time is limited, and the price increase and environmental pollution by the battery may occur. .

Korean Unexamined Patent Publication No. 2010-0077489 (August 11, 2010) discloses a method of detecting received power of a tag received signal from at least one representative RFID tag through a plurality of antennas, and a target RFID to be recognized through the plurality of antennas. Detecting a received power of a tag received signal from a tag, and determining a position of the recognized RFID tag based on a received power of the representative RFID tag and a received power of the recognized RFID tag. There is no alternative to the technique of the recognition method or the technique of supplying power for the RFID tag to operate.

An object of the present invention is to provide an active spin RFID tag with low power consumption and small size, mass production, integration and portability so that RFID tag operation can be performed even with a small amount of power produced by energy harvesting without providing a separate battery. do.

Active spin RFID tag according to the present invention for solving the above problems is to receive the energy harvesting means for harvesting the surrounding energy, the power harvested by the energy harvesting means without having a separate power supply of a predetermined frequency A spin oscillator for outputting an oscillation signal and a spin modulator for modulating the RFID data to the oscillation signal and outputting the RF signal.

As another embodiment of the present invention, an active spin RFID integrated circuit chip according to the present invention integrates the spin oscillator and the spin modulator on a substrate, and the energy harvesting means is a photoelectric device, a thermoelectric device, a wireless device, or a piezoelectric device. It is characterized by at least one.

As another embodiment of the present invention, the electronic door lock system according to the present invention receives and demodulates an active spin RFID tag and an RF signal for outputting a modulated RF signal using an oscillation signal output by a spin oscillator as a carrier signal. It characterized in that it comprises a door lock device including a reader for controlling the opening of the door.

As another embodiment of the present invention, the active spin RFID tag according to the present invention is provided with energy harvesting means for harvesting ambient energy, and is supplied with the power produced by the energy harvesting means without having a separate battery. And a reset unit for generating an oscillation signal and modulating the RFID data to output an RF signal, and a reset unit for generating an electric or magnetic signal for initializing the spin modulator.

The present invention uses a very low power spin oscillator as an oscillator instead of a conventional VCO (voltage controlled oscillator) consisting of an inductor and a capacitor, so even when a small amount of electricity is supplied using an energy harvesting means without a separate battery, Active RFID tag operation can be implemented, and the spin oscillator can be easily miniaturized and integrated, thereby reducing manufacturing cost and mass production.

While the performance of the conventional passive RFID tag is about 500㎼ power consumption, 100kbps communication speed, the size is more than 2.5x1mm, the present invention is active, but the conventional passive RFID tag power consumption 1/3 level, communication speed 200 times As described above, the tag size can be implemented at 1/100 times or less, and thus, the active RFID tag can be competitively implemented.

The present invention is environmentally friendly because it can be used permanently as an active RFID tag that supplies power to the RFID tag by energy harvesting without a separate battery.

1 is an active RFID tag according to the prior art.

Figure 2 is a general cross-sectional structure of the spin oscillator and a graph of the frequency characteristics according to the input current.

3 is an active spin RFID tag according to a first embodiment of the present invention.

4 is an active spin RFID tag according to a second embodiment of the present invention.

5 is an active spin RFID tag according to a third embodiment of the present invention.

6 is an active spin RFID tag according to a fourth embodiment of the present invention.

7 is an active spin RFID tag according to a fifth embodiment of the present invention.

8 is an active spin RFID tag according to a sixth embodiment of the present invention.

9 is an active spin RFID tag according to a seventh embodiment of the present invention.

10 is an active spin RFID tag according to an eighth embodiment of the present invention.

11 is an active spin RFID tag according to a ninth embodiment of the present invention.

12 is a shield formed on the active spin RFID tag of the present invention.

FIG. 13 illustrates an electronic door lock system to which an active spin RFID tag is applied. FIG.

Hereinafter, specific embodiments for the practice of the present invention will be described with reference to the drawings.

The present invention relates to a RFID tag technology using a spin oscillator combined with spintronics technology and RF technology. The present invention uses a low power consumption spin transfer torque (STT) device for an oscillator and a modulator in an RFID tag, and uses only RFID as an energy harvesting means to collect and recycle the surrounding energy and convert it into electricity without a separate battery. The invention is implemented tag.

Energy harvesting is a technology that collects energy that is thrown away or consumed in everyday life and recycles it into electric power. It harvests vibration, human movement, light, heat, and electromagnetic waves to produce power. The amount of conversion of electrical energy produced by energy harvesting is very small. Power harvesting by energy harvesting is in the microwatt (μW) level, and often in milliwatts (mW) level, in fact, there is a problem that the integrated circuits in the RFID tag cannot be driven smoothly by the power produced by the energy harvesting.

The present invention uses a conventional voltage controlled oscillator (VCO) and a modulator by implementing a spin oscillator having a low power characteristic and outputting an oscillation signal of a predetermined frequency when an electrical signal is applied as a communication oscillator and a modulator. In this case, it solves the problem that power consumption is too large to operate only with energy harvesting, and provides an active spin RFID tag that can operate only with the power produced by energy harvesting.

1. 실시예 1Example 1

As an embodiment of the present invention, the active spin RFID tag shown in FIG. 3 comprises an energy harvesting means 1, a spin oscillator 2, a spin modulator 3 and an antenna 5.

The energy harvesting means 1 converts ambient light energy, thermal energy, mechanical energy, and wireless energy, such as sunlight, radio waves, heat, vibrations, and wireless signals, into electrical energy to convert each component of the RFID tag (e.g., For example, power is supplied to the spin oscillator and spin modulator of FIG. The energy harvesting means 1 may be a photoelectric device, a piezoelectric device, a thermoelectric device and a wireless device.

The spin oscillator 2 is supplied with a small amount of electricity produced by the energy harvesting means 1 as electric power to be driven without a separate power source to output a carrier wave having a constant frequency. Since the spin oscillator 2 consumes less power than the conventional VCO, the effect of the spin oscillator 2 when combined with the energy harvesting means 1 is maximized. In addition, when the spin oscillator 2 connects a plurality of spin oscillators in series or in parallel to form an array structure of the spin oscillators, the output signals of each spin oscillator are synchronized or phase-tuned to sum the output signals. Because of its output, it can be applied not only to short-range wireless communication but also to medium and long-range wireless communication. In addition, by utilizing an array structure, direct modulation can be implemented using spin technology, so that not only the oscillation function but also the modulation function can be implemented. In addition, the spin oscillator 2 may be configured of at least one oscillator to output a waveform of a spin oscillation signal having various frequencies used for modulation when the applied current or voltage is adjusted for each spin oscillator.

As shown in FIG. 2, the spin oscillator 2 may be implemented as a multilayer thin film structure of a pinned magnetic layer / nonmagnetic layer / free magnetic layer. Alternatively, the spin oscillator 2 may be implemented as a tunneling magnetoresistance (TMR) device having a nonmagnetic layer as an insulating layer, and a giant magnetoresistance (GMR) device having a nonmagnetic layer as a conductive layer. The spin oscillator 2 may output the oscillation signal by precessing the magnetization direction of the free magnetic layer using the spin transfer torque in the above structure. The spin oscillator 2 may be implemented with various spin transfer torque type devices, for example, nano contacts, nano pillars, or magnetic vortex structures, and the like, and are not limited to specific device types. Do not. The spin oscillator 2 is input to the oscillator as shown in FIGS. 2 (b) and 2 (c) because it outputs an oscillation signal having a frequency that changes according to the input current as well as an operation caused by the amount of change in the intensity of the surrounding magnetic field. The frequency can be controlled by controlling the current as well as the strength of the magnetic field.

The spin modulator 3 modulates information (RFID data) detected by a sensor (shown in FIG. 8) together with a unique ID of an RFID tag through the oscillation signal output from the spin oscillator 2. Output as RF signal.

The spin modulator 3 modulates a unique ID or information (RFID data) detected by a sensor (shown in FIG. 8) through the oscillation signal output from the spin oscillator 2 and outputs the RF signal.

The spin modulator 3 may form a spin transfer torque element in an array structure to modulate the input RFID data and output a modulated signal. The spin modulator 3 comprises a modulator implemented by spintronics technology. Hereinafter, in the present invention, the configuration of the spin oscillator 2 and the spin modulator 3 are separated and described, but the spin oscillator 3 may include a structure including the spin oscillator 2.

The spin modulator 3 includes on-off keying (OOK) modulation, amplitude-shift keying (ASK) modulation, frequency shift keying (FSK) modulation or phase shift keying (phase). shift keying (PSK) modulation may combine one or two or more modulation functions. The spin modulator 3 can modulate sequentially or simultaneously when two or more modulations are used.

The antenna 5 is preferably implemented as a highly directional antenna having a reflector and a director. In this case, since the sensitivity to radio waves is high and the directivity is high, the spin oscillator 2 Even if the output level of the oscillation signal is small, the reception sensitivity of the external RFID reader can be improved.

2. 실시예 22. Example 2

The active spin RFID tag shown in FIG. 4 as a second embodiment of the present invention includes an energy harvesting means 1, a spin oscillator 2, a spin modulator 3, a reset unit 14, and an antenna 5. do. Since the same structure as the above-mentioned structure has the same principle and function, the description about the function is abbreviate | omitted.

The reset unit 14 may provide circuits (eg, the spin oscillator 2 and the spin modulator 3) inside the active spin RFID tag due to an abnormal output RF signal of the RFID tag, a malfunction of the RFID tag, or a user's need. ), The energy harvesting means 1 is initialized. Since the spin oscillator 2 has a property that can be initialized by reaching a self saturation state in a parallel state or an anti-parallel state, the reset unit 14 may rotate the spin in a reset coil. The spin oscillator 2 can be initialized by applying a current of sufficient strength to obtain the magnetic field required for the reset of the oscillator 2. Alternatively, the reset unit 14 may be configured as a reset holder separately from the active RFID tag. The reset holder has a slot for inserting and removing a plate, such as a card, and a permanent magnet is disposed above and below to form a magnetic field. When the RFID tag with the spin oscillator 2 is inserted into the reset holder, the information stored in the internal circuit can be initialized by the magnetic field.

3. 실시예 33. Example 3

As the third embodiment of the present invention, the active spin RFID tag shown in FIG. 5 includes an energy harvesting means 1, a power control unit 11, a spin oscillator 2, a spin modulator 3, and an antenna 5. do.

The power control unit 11 outputs a non-uniform electric signal produced by the energy harvesting means 1 with a constant and stable current or voltage. Since the spin oscillator 2 varies in frequency characteristic sensitively to the applied current, the power control unit 11 generates a stable current having a predetermined magnitude and applies it to the spin oscillator 2, thereby outputting from the spin oscillator 2. The frequency of the oscillation signal may be fixed without changing the constant frequency. In addition, the power control unit 11 may receive electricity from the energy harvesting means 1 as an input signal to supply a stable power to the spin modulator 3 by maintaining a constant voltage level, thereby reducing malfunction of the RFID tag. Can be.

4. 실시예 44. Example 4

As a fourth embodiment of the present invention, the active spin RFID tag shown in FIG. 6 includes an energy harvesting means 1, a spin oscillator 2, a spin modulator 3, an amplifier 10, and an antenna 5. do.

The amplifier 10 may compensate for a small power intensity of the output signal of the spin oscillator 2 by amplifying the output power of the spin oscillator 2 or the output power of the spin modulator 3.

5. 실시예 55. Example 5

The active spin RFID tag shown in FIG. 7 as a fifth embodiment of the present invention comprises an energy harvesting means 1, a battery 9, a spin oscillator 2, a spin modulator 3 and an antenna 5. .

The present invention is operable because it does not include a separate storage battery 9 and generates electricity even by the energy harvesting means 1 alone, because the power consumption is low due to the characteristics of the spin oscillator 2. However, when additional circuits such as amplifiers with high power consumption are included in the active RFID tag or when a large power level is output by airwaves through the antenna 5, the power harvesting means 1 may limit the power. The battery 9 can be added to supply power.

6. 실시예 66. Example 6

The active spin RFID tag shown in FIG. 8 as a sixth embodiment of the present invention includes an energy harvesting means 1, a spin oscillator 2, a spin modulator 3, a sensor 7 and an antenna 5. .

The sensor 7 detects gas, temperature, light, pressure, wave, mass, concentration, pulse, brain wave, blood sugar or location information and outputs a detection signal. According to various sensors 7, the active spin RFID tag according to the present invention can be applied to various fields such as environmental sensing, human body sensing, flora and fauna sensing or device motion sensing. When the RF signal containing the information of the detection signal from the sensor 7 is transmitted through the antenna 5, the external RFID reader obtains information corresponding to the purpose of the RFID tag. When the signal sensed by the sensor 7 is transmitted to the spin modulator 3 as RFID data, the spin modulator 3 modulates the RFID data and transmits the RF data as an RF signal, and an external RFID reader is used as the sensor 7. Can detect the detected signal.

7. 실시예 77. Example 7

As an seventh embodiment of the present invention, the active spin RFID tag shown in FIG. 9 includes an energy harvesting means 1, a spin oscillator 2, a spin modulator 3, a memory 8, a sensor 7 and an antenna ( 5) is included.

The memory 8 stores the detection signal sensed by the sensor 7 for a predetermined time, and may transmit the stored value through the spin oscillator 2 and the spin modulator 3 at a value greater than or equal to the reference value. It is also possible to selectively output suitable data stored in the memory 8 according to various situations of the sensor (s). The memory 8 may be a memory chip, a register or a flip-flop.

8. 실시예 88. Example 8

As an eighth embodiment of the present invention, the active spin RFID tag shown in FIG. 10 includes an energy harvesting means 1, a spin oscillator 2, a spin modulator 3, a sensor 7, a memory 8, and a controller ( 4) and an antenna 5.

The controller 4 reads the information stored in the memory 8 and outputs RFID data to the spin modulator 3. The controller 4 performs a determination operation. The controller 4 may use a 1 to 32 bit controller, but the lower bit controller is more advantageous to low power operation, it is preferable to use a controller having a minimum appropriate bit according to the capacity of the determination operation. The controller 4 may further include at least one of a counter, an input / output interface unit, a memory, an analog to digital converter, and a digital to analog converter. The controller 4 is preferably designed to have the minimum structure required for the application operation in terms of power consumption, area, and manufacturing cost.

The sensor 7 can sense various information as described in the sixth embodiment. For example, if the sensor 7 detects a gas concentration, the controller 4 receives the gas concentration detected by the sensor 7 to determine whether the gas concentration is equal to or higher than the reference concentration, If it is determined that the abnormality is transmitted to the spin modulator 3, the sensing signal is transmitted to the spin modulator 3 as RFID data. The spin modulator 3 modulates the RFID data using the oscillation signal from the spin oscillator 2 and outputs it to the antenna 5. The modulated signal is transmitted to the user's RFID reader and immediately knows the gas concentration abnormality and gas state information.

9. 실시예 99. Example 9

As an ninth embodiment of the present invention, the active spin RFID tag shown in FIG. 11 includes an energy harvesting means 1, a spin oscillator 2, a spin modulator 3, a sensor 7, a counter 6, a memory ( 8) and an antenna 5.

The counter 6 performs a periodic operation or an operation by an external command. By the operation of the counter 6, the sensing signal output from the sensor 8 or the output of the memory 8 may be wirelessly transmitted at a predetermined period. The counter 6 performs a sequential operation flow.

Although not shown in FIGS. 3 to 11, the electricity produced by the energy harvesting means 1 is not only a spin oscillator 2 but also a spin modulator 3, a counter 6, a sensor 7, and an amplifier ( 10), the power control unit 11, the reset unit 14, the memory 8, and the controller 4 may also be supplied to each other so as not to have a separate storage battery 9.

10. 실시예 1010. Example 10

12 is a view showing a shield 15 formed in the active spin RFID tag of the present invention.

The shield part 15 forms a shield layer on the outside of the spin oscillator 2 so that the shield layer is shielded so as not to affect the oscillation signal of the spin oscillator 2 by an unwanted magnetic field or electromagnetic wave flowing from the outside. The abnormal operation of the tag can be prevented. As a material of the shield layer, when the non-magnetic metal having a low permeability is used, it is possible to prevent the operation of the spin oscillator 2 against electromagnetic waves. In contrast, when a ferromagnetic metal having a high permeability is used, it is preferable to use a ferromagnetic material as well as electromagnetic waves and shielding by an unwanted magnetic field. The permeability of the material is 16 for ferrite, 100 for iron, 100 to 600 nickel, and 8,000 for iron nickel alloy (NiFe). Since iron nickel alloy (NiFe) is inexpensive and good in performance, iron nickel alloy (NiFe) is preferable as a material of the shield part 15. When the permeability of the shield 15 is preferably 10 or more, the operation of the spin oscillator 2 is safe from external influences. Although not shown, the shield part 15 may include a grounding mechanism formed in the shielding portion 15 and an electronic filter (EMI filter) that may be provided between the shielding portion 15 and the grounding mechanism. have.

In addition, the present invention may implement an active spin RFID integrated circuit chip by integrating the energy harvesting means 1, the spin oscillator 2 and the spin modulator 3 on a substrate as shown in FIG. . In particular, spin oscillators and spin modulators are compatible with CMOS processes, allowing them to be integrated such as memories, amplifiers, counters, controllers, and sensors. As the energy harvesting means 1, a piezoelectric element, a thermoelectric element, an optoelectronic element, and a wireless electric conversion element may be integrated into one substrate or may be configured as a hybrid.

11. 실시예 1111.Example 11

Among the various embodiments of the present invention, as an example, the active spin RFID tag 20 may be utilized in an electronic door lock system. As shown in FIG. 13, the active RFID tag 20 in which unique identification information is recorded for opening a door may be a door lock device ( Adjacent to 30), the door lock device 30 is operated by an electric spin oscillator produced by the energy harvesting means 1 in the RFID tag, even if it does not transmit power wirelessly or transmit power. When the RF signal is output, the reader embedded in the door lock device 30 reads the RF signal to open the door. In addition, as mentioned in the sixth embodiment, the sensor includes gas, temperature, light, pressure, wave, The detection signal may be output by detecting mass, concentration, pulse, brain wave, blood sugar, or location information. According to various sensors, the active spin RFID tag according to the present invention can be applied to various fields such as environment sensing, human body sensing, flora and fauna sensing or device motion sensing.

The active spin RFID tag according to the present invention can be utilized in the field of an active RFID tag system, a wireless communication system, and a ubiquitous sensor network system operated by its own power supply.

Claims

In an active RFID tag,

Energy harvesting means for harvesting ambient energy;

At least one spin oscillator for receiving the power produced by the energy harvesting means and outputting an oscillation signal of a predetermined frequency without having a separate battery;

And a spin modulator for modulating RFID data using the oscillation signal output from the spin oscillator to output the RF data as an RF signal.
The method of claim 1,

The energy harvesting means is an active spin RFID tag, characterized in that any one or a combination of optoelectronic devices, thermoelectric devices, piezoelectric devices and wireless electrical conversion devices.
The method of claim 1,

And a reset unit for initializing the energy harvesting means, the spin oscillator or the spin modulator.
The method of claim 3,

And the reset part is formed outside the RFID tag, and is a reset coil for making the spin oscillator in a self-saturation state in a balanced state or a semi-balanced state.
The method of claim 1,

And a shield formed outside the spin oscillator so as not to fall outside the spin oscillator to shield external magnetic fields or electromagnetic waves.
The method of claim 1,

The spin modulator includes on-off keying (OOK) modulation, amplitude-shift keying (ASK) modulation, frequency shift keying (FSK) modulation, and phase shift keying: PSK) An active spin RFID tag, comprising at least one modulation function, and wherein two or more modulations can be used to modulate sequentially or simultaneously.
The method of claim 1,

And an amplifier configured to amplify and output the intensity of at least one output signal of the output of the spin oscillator or the output of the spin modulator.
The method of claim 1,

Active spin RFID tag further comprises a sensor for sensing the environment.
The method of claim 8,

And a memory for storing the detection signal detected by the sensor.
The method of claim 8,

And a memory or a controller configured to receive the sensing signal sensed by the sensor as an input signal, determine the input signal, and transmit the corresponding data to the spin modulator.
The method of claim 8,

And a counter for periodically outputting a sensing signal sensed by the sensor to the spin modulator.
The active spin RFID integrated circuit chip of claim 1, wherein the active spin RFID tag is integrated on one substrate.
In an active RFID tag,

Energy harvesting means for harvesting ambient energy; and

Active spin RFID tag, characterized in that it comprises a spin oscillator for outputting the oscillation signal of a predetermined frequency when supplied with the power produced by the energy harvesting means without having a separate battery.
In an active RFID tag,

Energy harvesting means for harvesting ambient energy;

A spin modulator for generating an oscillation signal having a predetermined frequency, modulating RFID data, and outputting the RF signal as an RF signal by receiving electric power produced by the energy harvesting means without having a separate battery;

And a reset unit for generating an electrical or magnetic signal for initializing the spin modulator.
In order to initialize the active spin RFID tag of claim 1,

The holder for inserting and removing the active spin RFID tag in the form of a card is formed, and the reset holder, characterized in that the permanent magnet is arranged up and down to form a magnetic field.
The active spin RFID tag of claim 1 and

Environmental sensing, human body sensing, flora and fauna sensing, including sensors for outputting a sensing signal obtained by sensing at least one of gas, temperature, light, pressure, radio wave, mass, concentration, pulse, brain wave, blood sugar or location information to the spin modulator Or at least one of device operation sensing and electronic door lock sensing.