A bidirectional distance-enhanced passive RFID tag sensor based on a reflection amplifier

Abstract

This invention discloses a bidirectional distance-enhancing passive RFID tag sensor based on a reflective amplifier, comprising a reflective amplifier, an RFID chip, a matching network, a main control MCU, a bidirectional coupler, a first electrically adjustable array resonant structure, a second electrically adjustable array resonant structure, a first antenna, and a second antenna. The first pin of the bidirectional coupler is electrically connected to the matching network and the RFID chip in sequence. The second pin of the bidirectional coupler is electrically connected to the reflective amplifier. The second antenna is electrically connected to the input terminal of the second electrically adjustable array resonant structure. The output terminal of the second electrically adjustable array resonant structure is electrically connected to the third pin of the bidirectional coupler. The first antenna is electrically connected to the input terminal of the first electrically adjustable array resonant structure. The output terminal of the first electrically adjustable array resonant structure is electrically connected to the fourth pin of the bidirectional coupler. The main control MCU is electrically connected to the control terminals of the first electrically adjustable array resonant structure and the second electrically adjustable array resonant structure, respectively.

Description

Technical Field

[0001] This invention relates to the field of RFID radio frequency technology, and more specifically, to a bidirectional distance-enhancing passive RFID tag sensor based on a reflection amplifier. Background Technology

[0002] RFID technology is a low-cost technology with wide applications in retail and logistics. Because it utilizes antenna structures for sensing, RFID tags can incorporate sensing functionality without excessive power consumption. This allows RFID tags to be used for health monitoring of environmental parameters such as temperature and humidity, as well as structural parameters such as cracks and strain. However, due to limitations in reader transmission power and the relatively small backscattered (AM) signal, a major challenge for RFID systems is increasing their operating range.

[0003] To increase the reading distance of RFID tags, many scholars have proposed their own solutions. For example, the papers "Enhancement of RF Tag Backscatter Efficiency With Low-Power Reflection Amplifiers" published in IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES and "Tunneling RFID Tags for Long-Range and Low-Power Microwave Applications" published in IEEE JOURNAL OF RADIO FREQUENCY IDENTIFICATION both propose using a reflection amplifier (RA) to amplify the ambient backscatter (AM) signal, thereby increasing the RFID tag reading distance. However, these solutions all use a single-antenna RA, resulting in very low spatial isolation between the transmitting and receiving antennas. This makes them susceptible to intermodulation interference within the system, affecting information acquisition speed and preventing true transmission-receiver separation. Summary of the Invention

[0004] In order to address the shortcomings and defects of existing technologies, this invention proposes a bidirectional distance-enhanced passive RFID tag sensor based on a reflection amplifier.

[0005] To achieve the above-mentioned objectives of this invention, the technical solution adopted is as follows:

[0006] A bidirectional distance-enhancing passive RFID tag sensor based on a reflection amplifier, the device comprising a reflection amplifier for achieving bidirectional distance enhancement by amplifying forward link signals and backward link signals, an RFID chip, a matching network, a main control MCU, a bidirectional coupler, a first electrically adjustable array resonant structure, a second electrically adjustable array resonant structure, a first antenna for receiving signals transmitted by a reader, and a second antenna for transmitting signals.

[0007] The first pin of the bidirectional coupler is electrically connected to the matching network and the RFID chip in sequence.

[0008] The second pin of the bidirectional coupler is electrically connected to the reflective amplifier;

[0009] The second antenna is electrically connected to the input terminal of the second electrically adjustable array resonant structure;

[0010] The output of the second electrically adjustable array resonant structure is electrically connected to the third pin of the bidirectional coupler;

[0011] The first antenna is electrically connected to the input terminal of the first electrically adjustable array resonant structure;

[0012] The output terminal of the first electrically adjustable array resonant structure is electrically connected to the fourth pin of the bidirectional coupler;

[0013] The main control MCU is electrically connected to the control terminals of the first electrically adjustable array resonant structure and the second electrically adjustable array resonant structure, respectively.

[0014] In one specific embodiment, the sensor further includes an energy harvesting module for converting energy collected from the environment into electrical energy; wherein the energy includes electromagnetic waves or solar energy.

[0015] The energy harvesting module provides power to the main control MCU and the reflection amplifier, respectively.

[0016] In one specific embodiment, the impedance of the RFID chip serves as the load modulator of the reflection amplifier, and impedance matching is performed by a matching network to achieve the amplification function.

[0017] In a specific embodiment, the forward link signal specifically refers to: the electromagnetic wave signal received by the reader from the first antenna, which passes through the first electrically adjustable array resonant structure, the first pin of the bidirectional coupler, and the second pin of the bidirectional coupler, and is finally transmitted to the reflection amplifier for amplification;

[0018] The first electrically adjustable array resonant structure senses changes in the parameters of the input electromagnetic wave signal and converts the changes in the electromagnetic wave signal into an electrical signal.

[0019] In one specific embodiment, the reflective amplifier also outputs the amplified signal to the second pin of the bidirectional coupler, which then propagates to the first pin of the bidirectional coupler and is transmitted to the RFID chip via the matching network to activate the tag, thereby entering the working state.

[0020] In a specific embodiment, the backward link signal specifically refers to the signal that is modulated and output by the RFID chip and transmitted to the reflection amplifier for amplification through the first pin and the second pin of the bidirectional coupler.

[0021] In one specific embodiment, the reflection amplifier further includes transmitting the amplified signal sequentially through the second pin of the bidirectional coupler, the first pin of the bidirectional coupler, and then coupled to the third pin of the bidirectional coupler, before transmitting it sequentially through the second electrically adjustable array resonant structure and the second antenna.

[0022] The second electrically adjustable array resonant structure senses changes in the input electrical signal parameters and converts the changes in the electrical signal into electromagnetic wave signals.

[0023] In one specific embodiment, the main control MCU achieves large-scale sensing by regulating a first electrically adjustable array resonant structure and a second electrically adjustable array resonant structure.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention increases the communication distance of the RFID system and significantly improves communication performance by amplifying the input (forward link) and reflected output (reverse link) signals using a reflective amplifier (RA), enabling interconnection with cellular base stations. Wireless sensing is achieved by directly connecting the antenna to an electrically adjustable array resonant structure (no sensing device is required; sensing is achieved using radio frequency lines), expanding the sensing function of RFID tags. Controlling the first and second electrically adjustable array resonant structures via the main control MCU overcomes the low detection sensitivity caused by array coupling, improving sensing performance. The anti-collision protocol of the RFID chip allows multiple tags to work simultaneously, forming a multi-tag sensing network for ubiquitous monitoring applications. The bidirectional coupler described in this invention connects the reflective amplifier, the RFID chip, and the first and second antennas, achieving transceiver separation. Attached Figure Description

[0026] Figure 1 This is a circuit block diagram of the bidirectional distance-enhancing passive RFID tag sensor based on a reflection amplifier, according to the present invention. Detailed Implementation

[0027] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0028] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0029] The terms that may be involved in this embodiment are explained as follows:

[0030] RFID: Radio Frequency Identification

[0031] MCU: Microcontroller Unit

[0032] RA: Reflection Amplifier

[0033] AM: Ambient backscatter

[0034] Currently, commonly used wireless sensors include microstrip antenna sensors and dielectric resonators. Due to the distribution of the antenna resonant element field, they can only be used for hotspot detection in localized areas, failing to achieve large-scale detection and generally exhibiting low detection sensitivity. Array-based or traveling wave-based detection methods can achieve larger-area coverage, but their high operating frequencies result in short transmission distances or susceptibility to channel interference. Using complex network analyzers and other testing equipment is not conducive to on-site monitoring.

[0035] Existing RFID sensing technology is limited by the reader's transmit power and backscatter power, resulting in a short reading distance. Large-scale multi-tag sensing deployments require increasing the number of readers, thus increasing costs. While some researchers have proposed using a single-antenna RA amplifier to amplify the AM signal to improve RFID tag reading distance, this method cannot achieve transmitter-receiver separation. The spatial isolation between the transmitter and receiver antennas is very small, making them susceptible to intermodulation interference within the system, which affects information acquisition speed.

[0036] like Figure 1As shown, a bidirectional distance-enhancing passive RFID tag sensor based on a reflection amplifier is disclosed. The device includes a reflection amplifier for achieving bidirectional distance enhancement by amplifying forward and backward link signals, an RFID chip, a matching network, a main control MCU, a bidirectional coupler, a first electrically adjustable array resonant structure, a second electrically adjustable array resonant structure, a first antenna for receiving signals transmitted by a reader, and a second antenna for transmitting signals.

[0037] The first pin of the bidirectional coupler is electrically connected to the matching network and the RFID chip in sequence.

[0038] The second pin of the bidirectional coupler is electrically connected to the reflective amplifier;

[0039] The second antenna is electrically connected to the input terminal of the second electrically adjustable array resonant structure;

[0040] The output of the second electrically adjustable array resonant structure is electrically connected to the third pin of the bidirectional coupler;

[0041] The first antenna is electrically connected to the input terminal of the first electrically adjustable array resonant structure;

[0042] The output terminal of the first electrically adjustable array resonant structure is electrically connected to the fourth pin of the bidirectional coupler;

[0043] The main control MCU is electrically connected to the control terminals of the first electrically adjustable array resonant structure and the second electrically adjustable array resonant structure, respectively.

[0044] This invention provides a bidirectional distance-enhancing passive RFID tag sensor based on a reflective amplifier. By amplifying the input (forward link) and reflected output (reverse link) signals through a reflective amplifier (RA), the communication distance of the RFID system can be increased, significantly improving communication performance and enabling interconnection with cellular base stations. Wireless sensing is achieved by directly connecting the antenna to an electrically adjustable array resonant structure (no sensing device is required; sensing is achieved using radio frequency lines), expanding the sensing function of the RFID tag. Controlling the first and second electrically adjustable array resonant structures by the main control MCU overcomes the low detection sensitivity problem caused by array coupling, improving sensing performance. The anti-collision protocol of the RFID chip enables multiple tags to work simultaneously, forming a multi-tag sensing network for ubiquitous monitoring applications. The bidirectional coupler described in this invention connects the reflective amplifier, the RFID chip, and the first and second antennas, achieving transceiver separation.

[0045] Therefore, this invention increases the reading distance and expands the functionality of passive RFID tags, and realizes cellular passive Internet of Things.

[0046] In one specific embodiment, the sensor further includes an energy harvesting module for converting energy collected from the environment into electrical energy; wherein the energy includes electromagnetic waves or solar energy.

[0047] The energy harvesting module provides power to the main control MCU and the reflection amplifier, respectively.

[0048] This invention collects energy from the environment (such as electromagnetic waves, solar energy, etc.) through an energy harvesting module to power the main control MCU and the reflection amplifier, thereby realizing passive sensing.

[0049] In one specific embodiment, the impedance of the RFID chip serves as the load modulator of the reflection amplifier, and impedance matching is performed by a matching network to achieve the amplification function.

[0050] In a specific embodiment, the forward link signal specifically refers to: the electromagnetic wave signal received by the reader from the first antenna, which passes through the first electrically adjustable array resonant structure, the first pin of the bidirectional coupler, and the second pin of the bidirectional coupler, and is finally transmitted to the reflection amplifier for amplification;

[0051] The first electrically adjustable array resonant structure senses changes in the parameters of the input electromagnetic wave signal and converts the changes in the electromagnetic wave signal into an electrical signal.

[0052] In one specific embodiment, the reflective amplifier also outputs the amplified signal to the second pin of the bidirectional coupler, which then propagates to the first pin of the bidirectional coupler and is transmitted to the RFID chip via the matching network to activate the tag, thereby entering the working state.

[0053] In a specific embodiment, the backward link signal specifically refers to the signal that is modulated and output by the RFID chip and transmitted to the reflection amplifier for amplification through the first pin and the second pin of the bidirectional coupler.

[0054] In one specific embodiment, the reflection amplifier further includes transmitting the amplified signal sequentially through the second pin of the bidirectional coupler, the first pin of the bidirectional coupler, and then coupled to the third pin of the bidirectional coupler, before transmitting it sequentially through the second electrically adjustable array resonant structure and the second antenna.

[0055] The second electrically adjustable array resonant structure senses changes in the input electrical signal parameters and converts the changes in the electrical signal into electromagnetic wave signals.

[0056] In one specific embodiment, the main control MCU achieves large-scale sensing by regulating a first electrically adjustable array resonant structure and a second electrically adjustable array resonant structure.

[0057] In this embodiment, by controlling the first and second electrically adjustable array resonant structures through the main control MCU, the coupling effect generated by the array structure can be eliminated, the detection sensitivity can be effectively improved, and large-scale detection can be realized.

[0058] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A bidirectional distance-enhancing passive RFID tag sensor based on a reflection amplifier, characterized in that: The RFID tag sensor includes a reflective amplifier for bidirectional distance enhancement by amplifying forward and backward link signals, an RFID chip, a matching network, a main control MCU, a bidirectional coupler, a first electrically adjustable array resonant structure, a second electrically adjustable array resonant structure, a first antenna for receiving signals transmitted by the reader, and a second antenna for transmitting signals. The first pin of the bidirectional coupler is electrically connected to the matching network and the RFID chip in sequence. The second pin of the bidirectional coupler is electrically connected to the reflective amplifier; The second antenna is electrically connected to the input terminal of the second electrically adjustable array resonant structure; The output of the second electrically adjustable array resonant structure is electrically connected to the third pin of the bidirectional coupler; The first antenna is electrically connected to the input terminal of the first electrically adjustable array resonant structure; The output terminal of the first electrically adjustable array resonant structure is electrically connected to the fourth pin of the bidirectional coupler; The main control MCU is electrically connected to the control terminals of the first electrically adjustable array resonant structure and the second electrically adjustable array resonant structure, respectively. The impedance of the RFID chip serves as the load modulator of the reflection amplifier, and impedance matching is performed by the matching network to achieve the amplification function. The forward link signal specifically refers to the electromagnetic wave signal received by the reader from the first antenna, which passes through the first electrically adjustable array resonant structure, the first pin of the bidirectional coupler, and the second pin of the bidirectional coupler, and is finally transmitted to the reflection amplifier for amplification. The first electrically adjustable array resonant structure senses the changes in the parameters of the input electromagnetic wave signal and converts the changes in the electromagnetic wave signal into an electrical signal. The backward link signal specifically refers to the signal that is modulated and output by the RFID chip and transmitted to the reflection amplifier for amplification through the first pin and the second pin of the bidirectional coupler. The reflection amplifier further includes amplifying the signal, which is then sequentially passed through the second pin of the bidirectional coupler, the first pin of the bidirectional coupler, and then coupled to the third pin of the bidirectional coupler before being transmitted sequentially through the second electrically adjustable array resonant structure and the second antenna. The second electrically adjustable array resonant structure senses changes in the input electrical signal parameters and converts the changes in the electrical signal into electromagnetic wave signals.

2. The bidirectional distance-enhancing passive RFID tag sensor based on a reflection amplifier according to claim 1, characterized in that: The RFID tag sensor also includes an energy acquisition module for converting energy collected from the environment into electrical energy; wherein the energy includes electromagnetic waves or solar energy. The energy harvesting module provides power to the main control MCU and the reflection amplifier, respectively.

3. The bidirectional distance-enhancing passive RFID tag sensor based on a reflection amplifier according to claim 1, characterized in that: The reflection amplifier also outputs the amplified signal to the second pin of the bidirectional coupler, which then propagates to the first pin of the bidirectional coupler and is transmitted to the RFID chip through the matching network to activate the tag, thereby entering the working state.

4. The bidirectional distance-enhancing passive RFID tag sensor based on a reflection amplifier according to any one of claims 1 to 3, characterized in that: The main control MCU achieves large-scale sensing by regulating the first electrically adjustable array resonant structure and the second electrically adjustable array resonant structure.

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