An antenna pattern reconfigurable RFID tag

Abstract

The utility model discloses a kind of antenna directional diagram reconfigurable RFID label, belong to radio frequency identification (RFID) technical field. Including RFID label ontology, middle is set to fold dipole antenna and label chip, left and right two sides are set to left and right passive dipole, there is phase-change radio frequency switch each in its upper and lower, passive dipole effective electric length is controlled by switch on-off, realize omnidirectional / directional antenna multiplexing structure. When all switches are off or on, it is omnidirectional antenna, left and right side switch different on-off state can make antenna directional radiation left or right. The utility model utilizes phase-change radio frequency switch, with low power consumption, fast response, directional diagram power-off memory and the like advantages, can flexibly switch antenna radiation direction, solve the low gain of RFID label antenna in prior art and the problem of high power consumption, poor flexibility in the process of reconfigurable antenna radiation direction adjustment.

Description

Technical Field

[0001] This utility model relates to the field of radio frequency identification (RFID) technology, and in particular to an RFID tag with reconfigurable antenna pattern. Background Technology

[0002] Radio Frequency Identification (RFID) technology is a contactless data communication technology that uses radio waves. It boasts significant advantages such as small size, low power consumption, ease of embedding in other objects, contactless operation, reusability, and strong penetration. These advantages have led to its widespread application in numerous fields, primarily including item tracking, warehouse management, identification, retail anti-counterfeiting, and automated control. In item tracking, RFID technology can monitor the location of items in real time; in warehouse management, it can efficiently complete inventory checks and material scheduling; in identification, it provides reliable solutions for access control systems and electronic ticketing; in retail anti-counterfeiting, it helps consumers and merchants distinguish genuine products from counterfeit ones; and in automated control, it enables intelligent management of production processes.

[0003] In RFID systems, the tag antenna is a critical component, and its performance directly affects the overall communication quality. Typically, RFID tags use omnidirectional antennas to communicate with readers. An omnidirectional antenna radiates electromagnetic waves uniformly in 360° space. This radiation method offers advantages such as wide coverage, simple deployment, and flexible positioning, making it ideal for multi-tag, mobile scenarios. For example, in a large warehouse, multiple tags can be identified by readers in different locations, and communication can continue even with moving items. However, when there are materials such as metal or liquids around the tag, the poor anti-interference capability of omnidirectional antennas becomes apparent, resulting in a very short read / write distance and severely impacting communication quality.

[0004] To overcome the shortcomings of omnidirectional antennas in complex environments, directional antennas were developed. Directional antennas can concentrate the reception / transmission of electromagnetic waves in the direction of interest, giving them advantages such as strong anti-interference capability, long-distance communication, energy efficiency, and good security. In environments with metallic or liquid interference, directional antennas can concentrate energy in a specific direction, reducing interference and enabling longer-distance communication while also reducing energy consumption and improving communication security. However, directional antennas also have significant drawbacks. When the communication target is not in the antenna's transmission / reception direction, the communication distance is actually shorter than that of an omnidirectional antenna. In this case, to meet the requirements of long-distance communication, it is necessary to use mechanical rotation or electronic control to align the radiation direction of the directional antenna with the communication target, thus overcoming the limitations of complex environments.

[0005] Currently, technicians have developed various methods to change the radiation direction of directional antennas, but these methods all have certain limitations:

[0006] Mechanical control method: This method uses a servo motor to rotate the antenna and adjust the transmission direction. However, this method has several drawbacks. First, it has low deployment efficiency, requiring complex mechanical structure installation and debugging; second, it lacks flexibility, making it difficult to quickly adapt to changes in the location of different communication targets; third, it has a large response delay, making it unable to track dynamic targets in a timely manner; and fourth, the moving parts have short lifespans, requiring frequent maintenance and replacement over long-term use, increasing operating costs and maintenance difficulty.

[0007] Electronic control methods utilize PIN diodes, MEMS switches, or liquid crystal phase shifters to control the on / off state of the radio frequency path, thereby changing the transmission direction. However, these electronic components require a continuous power supply to maintain the on / off state, resulting in high energy consumption. Furthermore, they each have inherent limitations, such as the slow switching speed of PIN diodes, the low reliability of MEMS switches, and the long response time of liquid crystal phase shifters.

[0008] In summary, existing methods for changing the radiation direction of RFID directional antennas either suffer from high power consumption and poor flexibility, or require continuous power supply, failing to meet the low power consumption and high reliability requirements of RFID tags. Therefore, adjusting the antenna radiation pattern of RFID tags to achieve flexible configuration is particularly important in practical applications. To address these issues, this patent proposes an RFID tag directional antenna with a reconfigurable radiation pattern. By using a phase-change switch with memory function to change the antenna's radiation pattern, it overcomes the shortcomings of existing technologies. Utility Model Content

[0009] The purpose of this invention is to provide an RFID tag with a reconfigurable antenna pattern. By using a phase-change radio frequency switch to change the on / off state of the signal path, the antenna's radiation direction can be quickly adjusted. It also has the advantages of fast adjustment speed, memory retention of the radiation pattern after power failure, and low power consumption, thus solving the problems of high power consumption, poor flexibility, and large response delay in the adjustment of the radiation direction of RFID tag antennas in the prior art.

[0010] To achieve the above objectives, this utility model provides an RFID tag with reconfigurable antenna pattern. The RFID tag includes an RFID tag body, a bent-element antenna and a tag chip disposed in the middle of the RFID tag body. The tag chip is electrically connected to the bent-element antenna and is used to process signals sent by the reader in RFID communication. A left passive element and a right passive element are respectively disposed on the left and right sides of the RFID tag body. The left and right passive elements, together with the RFID tag body, constitute an omnidirectional / directional antenna multiplexing structure.

[0011] Preferably, a left phase-change RF switch one and a left phase-change RF switch two are respectively disposed above and below the left passive oscillator, and a right phase-change RF switch one and a right phase-change RF switch two are respectively disposed above and below the right passive oscillator. The left passive oscillator is connected to the extension conductor strip through the left phase-change RF switch one and the left phase-change RF switch two, and the right passive oscillator is connected to the extension conductor strip through the right phase-change RF switch one and the right phase-change RF switch two.

[0012] Preferably, the RFID tag body is provided with a control circuit, which is electrically connected to the left phase-change radio frequency switch one, the left phase-change radio frequency switch two, the right phase-change radio frequency switch one, and the right phase-change radio frequency switch two, and is used to control the on / off state of each phase-change radio frequency switch.

[0013] Preferably, when the left phase-change RF switch one, left phase-change RF switch two, right phase-change RF switch one, and right phase-change RF switch two are off, the left and right passive oscillators are disconnected from the extension conductor strip, and their lengths shorten. When the left phase-change RF switch one, left phase-change RF switch two, right phase-change RF switch one, and right phase-change RF switch two are on, the left and right passive oscillators are connected to the extension conductor strip through the phase-change switches, thus increasing the effective electrical length of the passive oscillators. Therefore, the effective electrical length of the passive oscillators can be controlled by controlling the on / off state of the switches.

[0014] Preferably, the RFID control circuit can control the on / off state of the phase-change RF switch. The phase-change RF switch has a memory function: the on / off state of the RF switch can be switched back and forth under the control of the RFID tag, and the on and off functions can remain unchanged for a long time after power failure.

[0015] Preferably, the antenna type and radiation direction can be adjusted when the switch is in different states, specifically in the following situations:

[0016] When all four switches—left phase-change RF switch one, left phase-change RF switch two, right phase-change RF switch one, and right phase-change RF switch two—are either off or on, the lengths of the conductor strips on both sides of the left and right passive vibrators are the same. At this time, the RFID tag antenna radiates omnidirectionally, meaning it functions as an omnidirectional antenna, radiating electromagnetic waves uniformly in 360° space, making it suitable for multi-tag, mobile scenarios.

[0017] When the left phase-change RF switch one and the left phase-change RF switch two are in the off state, and the right phase-change RF switch one and the right phase-change RF switch two are in the on state, the effective electrical length of the right passive vibrator becomes longer, the length of the left passive vibrator becomes shorter, and the antenna radiation direction is to the left. At this time, the tag antenna is used as a directional antenna, and the energy is concentrated and radiated to the left.

[0018] When both left phase-change RF switch one and left phase-change RF switch two are in the ON state, and both right phase-change RF switch one and right phase-change RF switch two are in the OFF state, the effective electrical length of the left passive vibrator increases, and the length of the right passive vibrator decreases. The antenna radiation direction is to the right, and it is used as a directional antenna, with energy concentrated and radiated to the right.

[0019] By flexibly controlling the on / off states of the four phase-change RF switches through the control circuit, the RFID tag antenna can switch between omnidirectional radiation and left / right directional radiation, thus meeting the communication needs of different application scenarios.

[0020] Therefore, the RFID tag with reconfigurable antenna pattern of the present invention, using the above structure, has the following beneficial effects:

[0021] (1) This utility model has multiple working modes and transmission directions, which can switch the tag antenna between omnidirectional and directional radiation, and the directional radiation direction can also be switched left and right. It can adapt to complex application environments. When there is interference in the surroundings, it can switch to directional mode to reduce the impact of interference; when it is necessary to cover readers in multiple directions, it can switch to omnidirectional mode to improve the reliability and flexibility of communication.

[0022] (2) This utility model uses a phase change radio frequency switch to realize the reconfigurability of the antenna. The phase change material has unique resistance state switching characteristics. Only a short pulse energy is needed when switching states. After the switching is completed, the current state can be maintained without continuous power supply. Therefore, it has the advantage of low power consumption.

[0023] (3) The phase-change RF switch of this utility model has a fast state switching speed and can quickly respond to control signals to achieve rapid adjustment of the antenna radiation direction. It can track the position changes of communication targets more timely, improving the real-time performance and reliability of the RFID system. The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of an RFID tag with reconfigurable antenna pattern according to the present invention;

[0025] Figure Labels

[0026] 1. RFID tag body; 2. Bending vibrator antenna; 3. Tag chip; 4. Right passive vibrator; 5. Left passive vibrator; 41. Right phase-change RF switch one; 42. Right phase-change RF switch two; 51. Left phase-change RF switch one; 52. Left phase-change RF switch two; 6. Control circuit. Detailed Implementation

[0027] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0028] Unless otherwise defined, the technical or scientific terms used in this utility model shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] like Figure 1 As shown, this utility model provides an RFID tag with reconfigurable antenna pattern, as detailed below:

[0030] The central part consists of the RFID tag body 1, a bent vibrator antenna 2, a tag chip 3, and a control circuit 6. A left passive vibrator 5 and a right passive vibrator 4 are respectively located on the left and right sides of the RFID tag. Above and below the left passive vibrator 5 and the right passive vibrator 4 are a left phase-change RF switch 51, a left phase-change RF switch 52, a right phase-change RF switch 41, and a right phase-change RF switch 42, respectively. The RFID tag body 1 and the left passive vibrator 5 and right passive vibrator 4 on both sides constitute an omnidirectional / directional antenna multiplexing structure. When the left phase-change RF switch 51, the left phase-change RF switch 52, the right phase-change RF switch 41, and the right phase-change RF switch 42 are off, the lengths of the left passive vibrator 5 and the right passive vibrator 4 are shortened. When these switches are on, the left passive vibrator 5 and the right passive vibrator 4 can be connected to the conductor strip of the extended section, thus increasing the effective electrical length of the passive vibrators. In other words, controlling the on / off state of the switches controls the length of the passive vibrators. Different switch states can adjust the antenna type and radiation direction. For example, when all four switches—left phase-change RF switch 51, left phase-change RF switch 52, right phase-change RF switch 41, and right phase-change RF switch 42—are either off or on, the lengths of the conductor strips on both sides of the left passive vibrator 5 and the right passive vibrator 4 are the same. In this case, the RFID tag antenna's radiation direction is omnidirectional, meaning the tag antenna is an omnidirectional antenna. When left phase-change RF switch 51 and left phase-change RF switch 52 are off, and right phase-change RF switch 41 and right phase-change RF switch 42 are on, the antenna's radiation direction is to the left, making it a directional antenna. Similarly, when left phase-change RF switch 51 and left phase-change RF switch 52 are on, and right phase-change RF switch 41 and right phase-change RF switch 42 are off, the antenna's radiation direction is to the right, also exhibiting directional characteristics.

[0031] Example 1: Implementation of Omnidirectional Antenna Mode

[0032] In this embodiment, the RFID tag antenna needs to be set to omnidirectional radiation mode to adapt to multi-tag, mobile application scenarios. The specific operation is as follows:

[0033] Control signals are sent to the left phase-change RF switch 51, left phase-change RF switch 52, right phase-change RF switch 41, and right phase-change RF switch 42 via the control circuit, causing all four switches to be in the off state (or all in the on state). At this time, the left passive vibrator 5 and the right passive vibrator 4 are disconnected from the extension conductor strip (or both are connected to the extension conductor strip), and the lengths of the left and right conductor strips of the left passive vibrator 5 and the right passive vibrator 4 are the same. Since the effective electrical length of the passive vibrators is consistent, the antenna's radiation direction is omnidirectional, radiating electromagnetic waves uniformly in space at 360°. In practical applications, such as large-scale warehouse management scenarios, multiple moving cargo tags can communicate with readers in different locations through this omnidirectional mode, achieving efficient inventory counting and material tracking.

[0034] Example 2: Implementation of Left-Directional Antenna Mode

[0035] When there are interference sources such as metal or liquid on the right side of the RFID tag, and it is necessary to concentrate the antenna radiation direction to the left, the following steps can be taken to achieve the left-directed mode:

[0036] The control circuit sends a signal to turn off left phase-change RF switches 51 and 52, and turn on right phase-change RF switches 41 and 42. At this time, the left passive vibrator 5 is disconnected from the extension conductor strip, shortening its length; the right passive vibrator 4 is connected to the extension conductor strip through the turned-on phase-change switches, increasing its effective electrical length. This structure causes the antenna to radiate to the left, concentrating energy radiation to the left. In practical applications, such as on a production line, when the reader is located on the left side of the tag and there is interference from metal equipment on the right, switching to the left-oriented mode can enhance the communication signal on the left, reduce the impact of interference on the right, and improve the stability and reliability of data transmission.

[0037] Example 3: Implementation of Right-Directional Antenna Mode

[0038] If the communication target is located to the right of the RFID tag, the antenna radiation direction needs to be adjusted to the right. The specific implementation method is as follows:

[0039] The control circuit controls left phase-change RF switches 51 and 52 to be in the ON state, while right phase-change RF switches 41 and 42 are in the OFF state. At this time, the left passive vibrator 5 is connected to the extension conductor strip, increasing its effective electrical length; the right passive vibrator 4 is disconnected from the extension conductor strip, shortening its length. The antenna's radiation direction is to the right, achieving directional radiation to the right. For example, in a retail anti-counterfeiting scenario, when the label is affixed to the right side of the product and the reader is located on the right side for scanning, switching to the right-oriented mode can improve recognition efficiency and accuracy, ensuring reliable transmission of anti-counterfeiting information.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solution of this utility model, and these modifications or equivalent substitutions cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of this utility model.

Claims

1. An RFID tag with reconfigurable antenna pattern, characterized in that: The RFID tag body includes a bent vibrator antenna and a tag chip in the middle. A left passive vibrator and a right passive vibrator are respectively set on the left and right sides of the RFID tag body. A left phase-change radio frequency switch one and a left phase-change radio frequency switch two are respectively set above and below the left passive vibrator. A right phase-change radio frequency switch one and a right phase-change radio frequency switch two are respectively set above and below the right passive vibrator.

2. The RFID tag with reconfigurable antenna pattern according to claim 1, characterized in that: The left passive oscillator is connected to the extension conductor strip via left phase-change RF switch one and left phase-change RF switch two, and the right passive oscillator is connected to the extension conductor strip via right phase-change RF switch one and right phase-change RF switch two.

3. The RFID tag with reconfigurable antenna pattern according to claim 1, characterized in that: The RFID tag body, together with the left and right passive vibrators, forms an omnidirectional / directional antenna multiplexing structure.

4. The RFID tag with reconfigurable antenna pattern according to claim 1, characterized in that: The RFID tag body contains a control circuit, which is electrically connected to the left phase-change RF switch one, the left phase-change RF switch two, the right phase-change RF switch one, and the right phase-change RF switch two.

5. The RFID tag with reconfigurable antenna pattern according to claim 1, characterized in that: The bent dipole antenna is electrically connected to the tag chip.

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