Antenna, electronic tag and circuit board

Abstract

The embodiment of the present application discloses an antenna, an electronic tag and a circuit board, and relates to the technical field of communication equipment, and the antenna comprises: an impedance matching ring and at least two wave-shaped radiation arms uniformly arranged in the interior of the impedance matching ring; the first end of the wave-shaped radiation arm is electrically connected with the impedance matching ring, and the second end of the wave-shaped radiation arm is used for being electrically connected with a chip; the wave-shaped radiation arm comprises at least one wave crest and at least one wave trough, the amplitude of the at least one wave crest and the amplitude of the at least one wave trough both decrease along a set direction, and the set direction is a direction along a transverse perpendicular line of the wave crest of the corresponding wave-shaped radiation arm away from the center of the impedance matching ring. The technical scheme of the embodiment of the present application can solve the problem of a large size of an existing electronic tag antenna, and the effect of reducing the size of an electronic tag by reducing the size of an antenna is achieved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of communication devices, and particularly relate to an antenna, an electronic tag and a circuit board. BACKGROUND

[0002] Ultra-high frequency radio frequency identification (UHF RFID) technology is a technology for automatically identifying targets through radio frequency signals, and is widely used in fields such as logistics, medical treatment and retail due to its advantages such as long reading distance, batch reading and fast data transmission rate.

[0003] The size of an existing electronic tag is usually large, and therefore the electronic tag is usually used as an additional electronic tag for a commodity with low appearance integration requirement and high single product value.

[0004] In the process of implementing the present application, the inventors have found that the existing electronic tag has the problem of large size due to the large size of the antenna. SUMMARY

[0005] Embodiments of the present application provide an antenna, an electronic tag and a circuit board to reduce the size of the antenna of the electronic tag.

[0006] In a first aspect, embodiments of the present application provide an antenna, comprising an impedance matching ring and at least two wave-shaped radiation arms uniformly arranged inside the impedance matching ring.

[0007] A first end of the wave-shaped radiation arm is electrically connected to the impedance matching ring, and a second end of the wave-shaped radiation arm is configured to be electrically connected to a chip.

[0008] The wave-shaped radiation arm comprises at least one wave crest and at least one wave trough, the amplitude of the at least one wave crest and the amplitude of the at least one wave trough both decrease along a set direction, and the set direction is a direction along a transverse perpendicular line of the wave crest of the corresponding wave-shaped radiation arm away from the center of the impedance matching ring.

[0009] In a second aspect, embodiments of the present application further provide an electronic tag, comprising a chip and the antenna according to any one of the embodiments.

[0010] The chip is arranged at the center of the impedance matching ring of the antenna, and the chip is electrically connected to the second end of each wave-shaped radiation arm.

[0011] In a third aspect, embodiments of the present application provide a circuit board, comprising a body and the electronic tag according to any one of the embodiments.

[0012] The body comprises a substrate and a circuit arranged on the substrate.

[0013] The electronic tag is arranged on the substrate, and the distance between the electronic tag and the circuit meets a set safety condition.

[0014] The embodiment of the application has the following advantages or beneficial effects:

[0015] The technical scheme of the antenna provided by the embodiment of the application adopts the wave-shaped radiation arm and arranges the wave-shaped radiation arm on the impedance matching ring, which can reduce the size of the antenna and thus the size of the electronic tag, and make the overall structure of the antenna simple and standard, so that the electronic tag can be manufactured with the identified object at one time, thereby effectively reducing the complexity of the manufacturing process. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structural schematic diagram of an antenna provided by the embodiment of the application;

[0017] Figure 2 is a structural schematic diagram of a wave-shaped radiation arm provided by the embodiment of the application;

[0018] Figure 3 is a structural schematic diagram of an electronic tag provided by the embodiment of the application;

[0019] Figure 4 is a schematic diagram of return loss of the electronic tag in an unloaded state provided by the embodiment of the application;

[0020] Figure 5 is a three-dimensional direction schematic diagram of electromagnetic distribution of the electronic tag in the unloaded state provided by the embodiment of the application;

[0021] Figure 6 is a two-dimensional direction schematic diagram of electromagnetic distribution of the electronic tag in the unloaded state provided by the embodiment of the application;

[0022] Figure 7 is a structural schematic diagram of a circuit board provided by the embodiment of the application;

[0023] Figure 8 is a schematic diagram of return loss of the electronic tag arranged on different substrate thicknesses in an unloaded state provided by the embodiment of the application. DETAILED DESCRIPTION

[0024] The application will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application, but not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings, but not all the structures.

[0025] Figure 1 is a structural schematic diagram of an antenna provided by the embodiment of the application. As shown in the figure, Figure 1With Figure 2 As shown in FIG. 1, the antenna comprises an impedance matching ring 11 and at least two wave-shaped radiation arms 12 evenly arranged inside the impedance matching ring 11; the first end of the wave-shaped radiation arm is electrically connected to the impedance matching ring, and the second end of the wave-shaped radiation arm is used for electrically connecting to a chip; the wave-shaped radiation arm 12 comprises at least one wave crest 123 and at least one wave trough 124, the amplitude of the at least one wave crest 123 and the amplitude of the at least one wave trough 124 both decrease along a set direction, and the set direction is a direction away from the center of the impedance matching ring 11 along the transverse perpendicular line of the wave crest 123 of the corresponding wave-shaped radiation arm 12.

[0026] Since the wave-shaped radiation arm 12 is arranged inside the impedance matching ring 11, the size of the impedance matching ring 11 is the size of the electronic tag. In an embodiment, the outer diameter of the impedance matching ring is in the range of 16-24 mm. Compared with the size of the existing electronic tag, this size can not only make the electronic tag have a longer data reading distance, but also expand the application scenarios of the electronic tag, such as making the electronic tag applicable to the identification of circuit boards.

[0027] On the one hand, the wave-shaped radiation arm 12 can reduce the area of the radiation arm while ensuring that the effective current transmission path remains unchanged, thereby reducing the size of the antenna and meeting the miniaturization needs of the electronic tag; on the other hand, the wave-shaped radiation arm 12 can adjust the working frequency and effective bandwidth of the chip, and the impedance bandwidth of nearly 700 MHz can improve the resistance of the electronic tag to the influence of the attached object.

[0028] It can be understood that the increase in the number of wave crests 123 and / or wave troughs 124 can help reduce the transverse size of the wave-shaped radiation arm 12, where the transverse size is the span size of the wave-shaped radiation arm in the direction of the transverse perpendicular line of the wave crest. Since the change of the wave crest and / or the wave trough can increase the overall effective bandwidth of the antenna, and by reducing the size of the impedance matching ring 11 and the overall effective bandwidth of the antenna, the size of the impedance matching ring can be reduced, i.e., the size of the antenna can be reduced, while ensuring that the overall effective bandwidth of the antenna is in a set bandwidth range, thereby reducing the size of the electronic tag.

[0029] In an embodiment, the antenna comprises four wave-shaped radiation arms 12 evenly distributed inside the impedance matching ring 11, i.e., the included angle between adjacent wave-shaped radiation arms is 90 degrees. This arrangement of wave-shaped radiation arms can improve the uniformity of the electric field distribution, reduce the dead zone coverage area of the near-field electronic tag reading and writing, expand the bandwidth of the antenna, and make the antenna bandwidth cover the ultra-high frequency band.

[0030] In an embodiment, as shown in FIG. 2, the wave-shaped radiation arm 12 comprises at least one wave crest 123 and at least one wave trough 124, the amplitude of the at least one wave crest 123 and the amplitude of the at least one wave trough 124 both decrease along a set direction, and the set direction is a direction away from the center of the impedance matching ring 11 along the transverse perpendicular line of the wave crest 123 of the corresponding wave-shaped radiation arm 12. Figure 1As shown, the antenna comprises two wave-shaped radiation arms 12 which are symmetric about the center of the impedance matching ring 11. Since the two wave-shaped radiation arms 12 are arranged inside the impedance matching ring 11, the antenna as a whole has a ring structure which helps to improve the impedance matching bandwidth of the antenna, alleviate the influence of the material of the substrate on the surface current, and thus improve the compatibility of the electronic tag.

[0031] In one embodiment, the outer diameter of the impedance matching ring 11 ranges from 16 mm to 24 mm. Compared with the size of the existing electronic tag, this size can not only make the electronic tag have a longer data reading distance, but also expand the application scenarios of the electronic tag, such as making the electronic tag applicable to the identification of circuit boards.

[0032] The two wave-shaped radiation arms arranged inside the impedance matching ring and symmetric about the center of the impedance matching ring also help to improve the uniformity of the electric field distribution, reduce the dead zone coverage area of the near-field electronic tag reading and writing, expand the antenna bandwidth, and make the antenna bandwidth cover the ultra-high radio frequency frequency band.

[0033] In one embodiment, the impedance matching ring 11 comprises at least two connection ports which are uniformly distributed, and the first ends of different wave-shaped radiation arms are connected to different connection ports, so as to improve the uniformity of the electric field distribution and reduce the dead zone coverage area of the antenna.

[0034] In one embodiment, the wave shape of the wave-shaped radiation arm 12 is a square wave (see Figure 1 ). This shape of the wave shape can improve the etching speed of the wave-shaped radiation arm, thereby improving the etching speed of the antenna, and the improvement of the etching speed of the antenna helps to improve the production speed of the electronic tag.

[0035] In one embodiment, the top of the wave peak of the wave-shaped radiation arm is arc-shaped, and the bottom of the wave valley is arc-shaped. This shape of the wave shape can improve the aesthetics of the wave-shaped radiation arm.

[0036] In one embodiment, as shown in Figure 1 and Figure 2 , the wave-shaped radiation arm 12 comprises two wave peaks 123 and two wave valleys 124, and the amplitude of the wave peak close to the second end 122 is greater than that of the wave peak close to the first end 121, and the amplitude of the wave valley close to the second end 122 is greater than that of the wave valley close to the first end 121. The number of wave peaks and wave valleys makes the antenna have good radiation performance while having a small size, so that the electronic tag has a small size and a longer response distance.

[0037] In one embodiment, the line connecting the second end 122 and the first end 121 of the wave-shaped radiation arm 12 is not parallel to the transverse perpendicular line of the wave crest 123 of the wave-shaped radiation arm 12. This position relationship makes the wave shape of the wave-shaped radiation arm more flexible while ensuring that the effective transmission path length of the current is unchanged.

[0038] It should be noted that the electronic tag in the embodiment can be set on the to-be-identified article by etching, and thus a substrate does not need to be separately set. It can be understood that the substrate-free setting manner can further reduce the size of the electronic tag, so that the electronic tag can be applied to special scenarios, such as the identification scenario of a circuit board.

[0039] The technical solution of the antenna provided in the embodiment of the application adopts the wave-shaped radiation arm and sets the wave-shaped radiation arm in the impedance matching ring, which can reduce the size of the antenna and thus the size of the electronic tag, and can make the overall structure of the antenna simple and standard, and easy to be integrally manufactured with the to-be-identified article, thereby effectively reducing the complexity of the manufacturing process.

[0040] Figure 3 The structural schematic diagram of the electronic tag provided in the embodiment of the application is shown. The electronic tag includes a chip 2 and the antenna described in the foregoing embodiments. The chip 2 is set in the center of the impedance matching ring 11 of the antenna, and the chip 2 is electrically connected to the second end 122 (see Figure 2 ) of the wave-shaped radiation arm 12.

[0041] In the case where the antenna includes at least two wave-shaped radiation arms, the impedance matching ring includes a corresponding number of uniformly distributed connection ports, and each connection port is set to connect the second end of a different wave-shaped radiation arm.

[0042] Since the electromagnetic field distribution of the antenna is uniform, the chip is set in the center of the impedance matching ring, that is, the center of the antenna, so that the overall symmetry of the chip is good, the electromagnetic distribution is uniform, and there is no obvious weakening point, and the chip is more easily read.

[0043] In one embodiment, the antenna's port impedance is set to be conjugate with the chip's port impedance, suitable for objects whose port impedance has minimal impact on the chip's port impedance. In this case, for chips with different port impedances, the antenna's port impedance can be adjusted by changing the radius or linewidth of the impedance matching loop, thus making the antenna's port impedance conjugate with the chip's port impedance. For example, if chip A's port impedance is greater than chip B's, then, while keeping the antenna linewidth the same, the radius of the impedance matching loop used to match chip A's port impedance is greater than the radius of the impedance matching loop used to match chip B's port impedance. In another example, if chip A's port impedance is greater than chip B's, then, while keeping the impedance matching loop radius the same, the linewidth of the impedance matching loop used to match chip A's port impedance is smaller than the width of the impedance matching loop used to match chip B's port impedance. This embodiment allows the user to determine the impedance matching loop parameters, such as radius and linewidth, based on the chip's port impedance without changing the waveform radiating arm.

[0044] In one embodiment, the port impedance of the antenna and the port impedance of the chip conform to a predetermined impedance relationship. This predetermined impedance relationship is that the sum of the chip's port impedance and the impedance of the object being identified affecting the chip is conjugate to the antenna's port impedance. Therefore, in electronic tag design, the impedance relationship between the antenna's port impedance and the target chip's port impedance can be determined based on the conjugate of the sum of the target chip's port impedance and the impedance of the object being identified affecting the chip, and an electronic tag conforming to this impedance relationship can be manufactured so that the electronic tag can be used to accurately identify the object being identified. Alternatively, electronic tags conforming to at least two impedance relationships can be designed; the user selects an electronic tag conforming to the corresponding impedance relationship based on the impedance of the object being identified affecting the chip. In this embodiment, the object being identified can be a circuit board. The affecting impedance is the change in the chip's port impedance caused by the influence of the identified object on its port impedance.

[0045] It is understandable that if the port impedance of chip A is the same as that of chip B, and the port impedance of antenna C matches the predetermined impedance relationship with that of chip A, then electronic tag M can be formed; similarly, if the port impedance of antenna C matches the predetermined impedance relationship with that of chip B, then electronic tag N can also be formed. When there are no special requirements for the chips in identifying the object, both electronic tag M and electronic tag N can be used to identify the same object.

[0046] In one embodiment, append Figure 4 The electronic tags were placed in the air in the [840MHz, 960MHz] frequency band (see... Figure 4 The return loss value (S11) within the rectangle is <-20dB (see [reference]).Figure 4 The minimum value of the curve in the figure), according to the industry cognition of the return loss, the size of the working frequency band of the antenna of the general electronic tag is taken as a criterion that the return loss value is <-10dB. Therefore, in this embodiment, the performance of the antenna of the electronic tag in the idle state is good within the working bandwidth; for example Figure 5 As shown in the figure, the gain of the antenna is about -15dB, and the theoretically identifiable distance is more than 50cm. When the electronic tag is in the far field region, the electromagnetic distribution is approximately omnidirectional in the H plane, and there is no obvious electric field weakening point, and it is easier to be read. The H plane: also called the magnetic plane, refers to the plane parallel to the magnetic field direction. It should be noted that the electronic tag in the idle state refers to the electronic tag placed in the air. Since the electronic tag in this embodiment does not have a substrate, it can be considered as an electronic tag in the idle state when it is not set to the identified object. Figure 6 As shown in the figure, the gain of the antenna is about -15dB, and the theoretically identifiable distance is more than 50cm. When the electronic tag is in the far field region, the electromagnetic distribution is approximately omnidirectional in the H plane, and there is no obvious electric field weakening point, and it is easier to be read. The H plane: also called the magnetic plane, refers to the plane parallel to the magnetic field direction. It should be noted that the electronic tag in the idle state refers to the electronic tag placed in the air. Since the electronic tag in this embodiment does not have a substrate, it can be considered as an electronic tag in the idle state when it is not set to the identified object.

[0047] In one embodiment, the electronic tag further includes a substrate, and the antenna and the chip are arranged on the substrate. The sum of the port impedance of the chip and the influence impedance of the substrate on the chip is conjugate to the port impedance of the antenna. The electronic tag in this embodiment can be used for the identified object which cannot use etching method to set the electronic tag.

[0048] The electronic tag in this embodiment only includes the impedance matching ring and the wave-shaped radiation arm, and does not include a substrate. Compared with the electronic tags in the prior art which all include a substrate, the size of the electronic tag can be further reduced without a special substrate.

[0049] The electronic tag provided by the embodiment of the present application has a small overall size, a simple structure, is easy to etch, has uniform electromagnetic distribution, has no obvious electromagnetic weakening point, and is easy to be read by a reader.

[0050] Figure 7 A structural schematic diagram of a circuit board provided by the embodiment of the present application. The circuit board includes a body and the electronic tag 1 described in the foregoing embodiments; the body includes a substrate 31 and a circuit 32 arranged on the substrate; the electronic tag 1 is arranged on the substrate 31, and the distance between the electronic tag 1 and the circuit 32 meets a set safety condition.

[0051] The material of the substrate can be selected from FR-4 grade materials. FR-4 is a code of a flame-resistant material grade, which means that a resin material must be able to extinguish itself after burning. It is not a material name, but a material grade. There are many types of FR-4 grade materials commonly used in circuit boards, but most of them are composite materials made of so-called Tera-Function epoxy resin, filler and glass fiber.

[0052] The circuit 32 can be any form of integrated or non-integrated circuit, and can include various types of components, such as capacitors, inductors, and integrated chips, etc.

[0053] In one embodiment, the safety condition is set as a safety distance condition, and the safety distance condition is set as greater than or equal to 0.05 wavelengths. For the UHF (Ultra High Frequency) band, the distance is about 1.5 cm. The distance can ensure that the electronic tag and the original circuit of the body do not affect each other

[0054] In one embodiment, the electronic tag 1 is arranged at a corner of the body. As shown in Figure 7 , the electronic tag is arranged at the upper left corner of the body. The arrangement does not affect the overall appearance of the circuit board, and generally does not increase the size of the body.

[0055] In one embodiment, the electronic tag is configured to be coplanar with the target circuit, which is a circuit or a part of a circuit. In the case where the circuit is only distributed on one side of the substrate, this embodiment makes it unnecessary to turn over the circuit board during the manufacturing process of the circuit board, which can improve the manufacturing speed of the circuit board.

[0056] In one embodiment, since the electronic tag is a low-profile structure, the height of the electronic tag is lower than or equal to the height of the set circuit, which is easy to realize the coplanar of the electronic tag and the set circuit. The set circuit is other circuit on the same side of the substrate as the electronic tag. This design can ensure that the circuit board can be identified in an ultra-high frequency manner, while not affecting the subsequent assembly of the circuit board.

[0057] In one embodiment, the port impedance of the antenna is conjugate to the target port impedance of the chip, and the target port impedance is determined based on the port impedance of the chip and the thickness of the substrate. Specifically, when the electronic tag is arranged on the substrate, the thickness of the substrate increases the port impedance of the chip, and the greater the thickness of the substrate, the greater the increase in the port impedance of the chip. Therefore, when designing the electronic tag, the impedance relationship between the port impedance of the antenna and the target port impedance of the chip can be determined based on the conjugate of the sum of the target port impedance of the chip and the influence impedance of the substrate and the chip and the port impedance of the antenna, and the electronic tag meeting the impedance relationship is etched on the circuit board including the substrate with the corresponding thickness.

[0058] As shown in Figure 8 , when the thickness of the substrate is 0.8 mm, 1 mm, and 1.5 mm, the return loss value (S11) is less than -20 dB (see Figure 8 ) in the [840 MHz, 960 MHz] frequency band (see the rectangular box in Figure 8The size of the working frequency band of the antenna of the general electronic tag is taken as a criterion with the echo loss value <-10dB, and thus the electronic tag of the embodiment covers the American standard [902, 928]MHz and the national standard [920, 925]MHz frequency band range; meanwhile, it is shown that when the electronic tag is etched to the substrate with the thickness of 0.8mm, 1mm and 1.5mm, the performance of the electronic tag is almost unchanged, and the electronic tag has good stability.

[0059] The electronic tag is arranged on the circuit board by etching, so that the electronic tag takes the substrate of the circuit board as a substrate, that is, a separate substrate for the electronic tag is not needed.

[0060] When the electronic tag in the circuit board enters the identification range of the reader, the antenna of the electronic tag receives the data reading information sent by the reader, and analyzes the data reading information, activates the chip based on the analysis result, acquires the identification data stored in the chip, encodes the identification data and outputs the encoding result. The reader receives the encoding result through its own antenna, determines the identification data corresponding to the encoding result, and the identification data is the identity of the circuit board.

[0061] The technical scheme of the circuit board provided by the embodiment of the present application has the advantages that the overall structure of the electronic tag is simple and symmetrical, so that the etching operation of the body circuit and the electronic tag can be completed at one time; the electronic tag adopts a low profile structure, so that the electronic tag and the same-side circuit of the substrate can be coplanar and fully integrated with the identified object; and the electronic tag can be uniquely identified and has privacy, which is beneficial to the anti-counterfeiting requirement of the identified object.

[0062] Note that the above are only the preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. An antenna, characterized in that, It includes an impedance matching ring and at least two waveform radiating arms that are uniformly arranged inside the impedance matching ring. The first end of the waveform radiating arm is electrically connected to the impedance matching loop, and the second end of the waveform radiating arm is used for electrical connection to the chip. The waveform radiating arm includes at least one peak and at least one trough. The amplitude of the at least one peak and the amplitude of the at least one trough decrease along a predetermined direction, which is the direction away from the center of the impedance matching ring along the transverse vertical line of the peak of the corresponding waveform radiating arm.

2. The antenna according to claim 1, characterized in that, The impedance matching ring includes at least two uniformly distributed connection ports, and the first ends of the different waveform radiating arms are connected to different connection ports.

3. The antenna according to claim 1, characterized in that, The waveform in the waveform radiating arm is rectangular.

4. The antenna according to claim 1, characterized in that, The waveform radiating arm includes two peaks and two troughs.

5. The antenna according to claim 1, characterized in that, The line connecting the second end and the first end of the waveform radiation arm is not parallel to the transverse perpendicular line of the wave crest of the waveform radiation arm.

6. The antenna according to claim 1, characterized in that, The outer diameter of the impedance matching ring is greater than or equal to 16 mm and less than or equal to 24 mm.

7. An electronic tag, characterized in that, include: The chip and the antenna according to any one of claims 1-6; The chip is disposed at the center of the impedance matching loop of the antenna, and the chip is electrically connected to the second end of each of the waveform radiating arms.

8. The electronic tag according to claim 7, characterized in that, The port impedance of the antenna and the port impedance of the chip conform to a set impedance relationship, wherein the sum of the port impedance of the chip and the impedance of the object being identified on the chip is conjugate to the port impedance of the antenna.

9. A circuit board, characterized in that, include: The body and the electronic tag as described in claim 7 or 8; The body includes a substrate and circuitry disposed on the substrate; The electronic tag is disposed on the substrate, and the distance between the electronic tag and the circuit meets the set safety conditions.

10. The circuit board according to claim 9, characterized in that, The electronic tag is placed in one corner of the body.

11. The circuit board according to claim 9, characterized in that, The port impedance of the antenna is conjugate to the target port impedance of the chip, and the target port impedance is determined based on the port impedance of the chip and the thickness of the substrate.

12. The circuit board according to any one of claims 9-11, characterized in that, The electronic tag is etched onto the substrate.

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