CN210109816U - Low-radiation anti-interference remote near field communication reader, detection device and system - Google Patents

Abstract

The utility model provides a low radiation anti-interference remote near field communication reader, detection device and system, includes antenna 2, with the signal processing unit that antenna 2 links to each other, its characterized in that: at least one large-area conductor 3 is arranged near the antenna 2, the conductor 3 is a planar conductor, the two planes of the antenna 2 and the conductor 3 are parallel to each other or form an acute angle with each other, the area of the conductor 3 is larger than that of the antenna 2, the thickness of the conductor 3 is larger than the skin depth of the electromagnetic wave corresponding to the operating frequency of the reader 1, the distance from the center of the plane of the conductor 3 to the plane of the antenna 2 is larger than 1/4 times of the radius of the antenna 2 and smaller than 1/12 of the wavelength of the electromagnetic wave corresponding to the operating frequency of the reader 1. The utility model discloses following beneficial effect has: the working distance is far (more than 10cm), the radiation disturbance is low, the anti-interference capability is strong, and meanwhile, the method is suitable for being deployed in near field communication detection equipment and a detection system, and is low in cost and easy to process.

Description

Low-radiation anti-interference remote near field communication reader, detection device and system

Technical Field

The utility model relates to a near field communication's reading ware, detection device and system, concretely relates to near field communication who reduces radiation disturbance, improves interference killing feature reads ware, detection device and detecting system.

Background

Near Field Communication (NFC), also called short-range wireless Communication, is a short-range high-frequency wireless Communication technology that allows contactless point-to-point data transmission and data exchange between electronic devices. NFC technology evolved from Radio Frequency Identification (RFID), the basis of which is RFID and interconnect technology.

An rfid (radio Frequency identification) technology, also called a radio Frequency identification technology, is a non-contact automatic identification technology. The RFID technology mainly uses radio frequency signals to generate an alternating magnetic field in a space coupling mode, so that the electronic tag obtains energy from the alternating magnetic field to realize contactless information transmission and achieves the aim of identification through the information transmission. An RFID system generally comprises three basic parts, a radio frequency tag, a reader and an information processing system. The radio frequency tags comprise coupling antennas and tag chips, each radio frequency tag has a unique electronic product code and is mounted on an object to be identified. The reader (also called as a card reader or a reader writer) is a device for reading tag information, can be externally connected with an antenna and used for sending and receiving radio frequency signals, and some readers can write information data into the radio frequency tags. The information processing system has the main function of processing information obtained by a reader-writer from a radio frequency tag, and the function relates to system application of realizing information encryption or security authentication and the like.

The RFID system can be divided into low frequency LF (Low frequency)30-300 KHz, medium frequency MF (Medium frequency)300-3MHz, High frequency HF (High frequency) 3-30MHz, very High frequency VHF (Veryhigh frequency)30-300MHz, and ultra High frequency UHF (ultra High frequency)300-3000MHz according to the working frequency. The working frequency ranges are different, and the characteristics and the application fields of the RFID are different.

The following table is a characteristic of a common operating frequency band of the RFID system.

The working frequency ranges are different, and the electromagnetic coupling modes between the radio frequency tag and the reader in the RFID system are also different.

For RFID systems with the working frequency below 100MHz, an inductive coupling mode is adopted. In the inductive coupling method, coupling is achieved by a spatial magnetic field, an antenna of a reader corresponds to a primary coil of a transformer, an antenna of a radio frequency tag corresponds to a secondary coil of the transformer, and a coupling magnetic field forms a closed loop between the coil (primary) of the reader and the coil (secondary) of the radio frequency tag, so that the inductive coupling method is also called a transformer method.

For the RFID system with the working frequency above 400MHz, an electromagnetic coupling mode is mainly adopted. In the electromagnetic coupling mode, an antenna of the reader directionally transmits a radio frequency signal generated by the reader into a space range in an electromagnetic wave mode to form an effective reading area of the reader, a radio frequency tag located in the effective reading area of the reader extracts a working power supply from an electromagnetic field transmitted by the antenna of the reader, and data information stored in the tag is transmitted to the reader through an internal circuit of the radio frequency tag and the tag antenna.

The difference between electromagnetic coupling and inductive coupling is that: in the electromagnetic coupling mode, the reader sends out the radio frequency signal in the form of electromagnetic wave; in the inductive coupling mode, the reader binds the radio frequency signal around the inductive coil of the reader, and communicates with the radio frequency channel between the reader antenna and the radio frequency tag antenna through the alternating closed coil magnetic field without radiating electromagnetic energy to the space.

NFC is a near field communication technology developed based on RFID technology. Like RFID, NFC also uses radio frequency signals to achieve contactless information transfer by spatial coupling, but there is a great difference between the two. The operating frequency of NFC is 13.56MHz, so that an inductive coupling mode is adopted. The working range of NFC is smaller than that of RFID, the working distance is not more than 10cm, generally about 3-5 cm, and the transmission range of RFID can reach more than 1 m.

The ISO/IEC 18092 standard defines the communication mode of the NFC interface and protocol. The NFC operating frequency is 13.56MHz, and the NFC operating frequency meets the current ISO/IEC 14443 standard (Type A/B) and FeliCa. NFC is very suitable for a wide range of industrial, environmental, and other applications, such as (1) monitoring, access control, and security, (2) electronic products, (3) automated manufacturing workflows, (4) healthcare, (5) payment systems, (5) transportation and automobiles, and the like.

But the NFC technology also has its disadvantage that the working distance is short. And a working distance of 10cm is far from sufficient in some application scenarios. Therefore, it becomes a practical need to extend the working distance of NFC. In order to increase the NFC working distance, the general approaches include increasing the excitation power of the reader antenna and increasing the size of the reader antenna, but this also brings new technical problems:

increasing the reader antenna excitation power increases the antenna radiation disturbance power, affecting/interfering with other nearby devices. Moreover, the high power of the antenna may cause the field strength in some areas close to the antenna to be high, and cause damage or damage to equipment, such as an electronic tag smart card, and the like, in the vicinity of the antenna. The increase in power is therefore limited.

Increasing the reader antenna size will increase the effective operating range of the antenna to excite the 13.56MHz magnetic field and will also increase the antenna radiation disturbance power to affect/disturb other nearby electrical/electronic equipment.

Due to the small size of the antenna, for example a circular loop antenna with a diameter of 10cm, it is very inefficient in receiving electromagnetic waves with a frequency around 13.56MHz, because its size is much smaller than the wavelength of the electromagnetic waves of 13.56MHz (about 22 meters in air). But as soon as the antenna size (diameter or diagonal) is increased, for example, 30cm or 50cm or more in diameter, the antenna reception is greatly improved. However, as the size of the antenna of the reader is increased, the reader inevitably receives more interference in the antenna environment when receiving communication signals. In this case, once the electromagnetic environment in which the reader operates is not good, the operating efficiency of the reader may be reduced or even the reader may not operate at all.

And when two measures of improving the excitation power of the reader antenna and increasing the size of the reader antenna are adopted, a magnetic field with proper field intensity and enough working distance can be excited and generated for NFC. But this still makes the radiation disturbance of the reader antenna very severe.

In the prior art, for the UHF RFID system, because the transmission distance of the electromagnetic wave generated by the reader antenna is long (generally > 1m), in order to avoid the electromagnetic wave generated by the reader antenna from interfering with surrounding devices or from interfering with adjacent reader antennas, in some UHF RFID systems, for example, in the card reading channel of the UHF RFID electronic tag, the electromagnetic wave generated by the reader antenna can be limited within the metal cover in a manner of the metal cover. Because the working frequency of the UHF RFID reader antenna is high, the size of the UHF RFID reader antenna is small, the wavelength of generated electromagnetic waves is usually 10-20 cm, and the electromagnetic waves can be reflected after touching a metal plane and cannot be diffracted to the back of the metal plate. Therefore, the metal cover can easily reflect and isolate electromagnetic wave signals, and achieves the effect of directional transmission and emission enhancement of the electromagnetic waves, so that the accuracy of identification of the electronic tags in the channel is higher.

However, as for the antenna of NFC, for reasons explained in detail below, when the antenna of NFC reader is used in a metal environment, since metal has strong reflectivity to electromagnetic waves, the card reading distance may become closer along with the signal attenuation, and in a serious case, even the card reading failure may occur. Therefore, it is very difficult or even impossible to reduce radiation disturbance and external interference by adding a metal plate near the antenna randomly for NFC. This is because NFC uses a near-field magnetic field excited by a reader antenna coil, which does not require or depend on electromagnetic waves radiating outward, and electromagnetic radiation of the reader antenna is not only a side effect caused by exciting the near-field magnetic field, which is not helpful for NFC, and adversely brings various electromagnetic compatibility problems, such as excessive radiation disturbance and communication interference. The operating frequency of the NFC antenna is only 13.56MHz, so the wavelength of the radiation disturbance generated by the NFC antenna is 22m, and if the size of the metal plate is smaller than the wavelength of the electromagnetic radiation, the electromagnetic radiation can easily bypass the metal plate, so that the isolation effect cannot be achieved. Moreover, if a metal plate is randomly arranged in a close range of the reader antenna, the magnetic flux of the antenna passes through the metal surface to generate an induced eddy current, and the eddy current can perform a reaction on the magnetic field of the antenna, so that the magnetic field generated by the antenna coil is weakened, and the performance and the working distance of the reader antenna are greatly influenced. And the matching and tuning of the antenna can be greatly influenced by the metal plate which is randomly arranged, and even the radio frequency transmitting circuit can be damaged under severe conditions.

Therefore, an NFC reader, a detection device, and a detection system are needed, which can increase the working distance of the near reader, reduce radiation disturbance, and improve the anti-interference capability.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a both can increase and read ware working distance, can reduce the NFC that radiation harass, improve the interference killing feature again and read ware, check out test set and detecting system.

In order to solve the problem existing in the background art, the utility model adopts the following technical scheme:

an NFC reader 1 comprises an antenna 2 and a signal processing unit connected with the antenna 2, and is characterized in that: at least one large-area conductor 3 is arranged near the antenna 2, the conductor 3 is a planar conductor, the two planes of the antenna 2 and the conductor 3 are parallel to each other or form an acute angle with each other, the area of the conductor 3 is larger than that of the antenna 2, the thickness of the conductor 3 is larger than the skin depth of the electromagnetic wave corresponding to the operating frequency of the reader 1, the distance from the center of the plane of the conductor 3 to the plane of the antenna 2 is larger than 1/4 times of the radius of the antenna 2 and smaller than 1/12 of the wavelength of the electromagnetic wave corresponding to the operating frequency of the reader 1.

The utility model discloses following beneficial effect has: the working distance is far (more than 10cm), the radiation disturbance is low, the anti-interference capability is strong, and meanwhile, the method is suitable for being deployed in NFC detection equipment and detection systems, and is low in cost and easy to process.

Drawings

Fig. 1 is a schematic structural diagram of the NFC reader 1 of the present invention.

Fig. 2 is a schematic side view of the NFC device 10 according to the first embodiment of the present invention.

Fig. 3 is a schematic side view of the NFC device 10 according to the second embodiment of the present invention.

Fig. 4 is a schematic side view of the NFC device 10 according to the third embodiment of the present invention.

Fig. 5 is a schematic side view of the NFC device 10 according to the fourth embodiment of the present invention.

Fig. 6 is a schematic side view of the NFC detection device 10 according to the fifth embodiment of the present invention.

Fig. 7 is a schematic side view of the NFC device 10 according to the sixth embodiment of the present invention.

Fig. 8 is a schematic side view of the NFC detection device 10 according to the seventh embodiment of the present invention.

Fig. 9 is a schematic side view of the NFC detection device 10 according to the eighth embodiment of the present invention.

Fig. 10 is a schematic side view of an NFC detection system 100 according to the ninth embodiment of the present invention.

Fig. 11 is a schematic view of the experimental measurement point of the NFC device 10 of the present invention.

In the drawings, the reference numbers correspond to the respective figures: the NFC detection system comprises an NFC reader 1, an antenna 2, a conductor 3, an NFC detection device 10 and an NFC detection system 100.

Detailed Description

The principles and features of the present invention are described below in conjunction with the following drawings, the examples given are only intended to illustrate the present invention and are not intended to limit the scope of the present invention.

In order to overcome NFC and read the ware for increase working range, and improve and read the problem that the radiation disturbance that brings easily exceeds standard, communication easily receives the interference behind ware antenna excitation power and the increase ware antenna size, the utility model discloses a after a large amount of analysis, calculation, emulation and experiments, improved NFC reader, detection device and detecting system's structure.

NFC reader 1

Referring to fig. 1, an NFC reader 1 of the present invention includes an antenna 2, and a signal processing unit (not shown in the figure) connected to the antenna 2. The structure of the reader of the present invention can adopt the structure of the NFC reader in the prior art, for example, the reader in patents CN100454328C and CN 208044610U. The utility model discloses a read ware because improve and read ware antenna excitation power and/or increase and read ware antenna size, therefore can realize remote reading. A large-area conductor 3 is arranged parallel or approximately parallel near the antenna 2. The distance d between the antenna 2 and the two planes of the conductor 3 is between 1/4 and 1 times the radius of the antenna. The area of the conductor 3 is not smaller than the area of the antenna 2. The thickness of the conductor 3 is greater than the skin depth of the electromagnetic wave at the operating frequency of the reader. Wherein the total length of the single antenna coil is no more than 11m (half wavelength of 13.56MHz electromagnetic wave in air).

The structure and the arrangement of the NFC reader 1 of the present invention are further described below.

Regarding the setting of the distance d between the antenna 2 and the conductor 3. The conductor 3 can generate an induced current to counteract part of the magnetic field of the antenna 2 under the action of the magnetic field of the antenna 2. The induced currents generated by a large area good conductor can be equivalent to a mirror antenna located symmetrically with respect to the conductor 3 in the antenna 2, the mirror antenna current being in the opposite direction to the antenna 2 current. Since the NFC operating frequency is 13.56MHz and the wavelength in air is about 22 meters, as long as the distance between the antenna 2 and the conductor 3 is less than 1/12 wavelengths (about 1.8 meters), the induced current of the conductor 3 will effectively cancel the far field radiation of the magnetic field of the antenna 2. Whereas if the conductor 3 is far less than 1/12 wavelengths (about 1.8 meters) from the antenna 2, the induced current of the conductor will largely cancel the far field radiation of the magnetic field of the antenna 2. However, the distance between the conductor 3 and the antenna 2 cannot be too small, otherwise the operating range of the reader 1 is severely affected. The farther the conductor 3 is from the antenna 2, the smaller the influence of the conductor 3 on the near-region electromagnetic field distribution of the antenna 2 and the weakening of the field strength, and otherwise, the larger the influence on the magnetic field distribution of the antenna 2 and the serious weakening of the field strength. In order to ensure the effects of suppressing radiation disturbance and resisting interference, when the distance between the conductor 3 and the antenna 2 is increased, the area of the conductor 3 must be increased at the same time to achieve a good effect. The distance between the conductor 3 and the antenna 2 is preferably between 1/4 and one times the radius of the antenna. If the antenna working range is located between the antenna and the conductor, the distance between the conductor and the antenna can be increased properly.

With respect to the relative position of the conductor 3 and the antenna 2. The antenna 2 and the conductor 3 are arranged parallel to each other. However, the antenna 2 may be at a certain angle (acute angle) with respect to the plane of the conductor 3, but this may affect the effect. When the antenna 2 is arranged opposite to two planes of the conductor 3, the projection of the antenna 2 on the plane of the conductor 3 should be close to the central position of the conductor 3, and the projection does not exceed the range of the conductor 2, otherwise, the radiation disturbance suppression and the anti-interference effect will be weakened.

Regarding the area and shape of the conductor 3. The area of the conductor 3 should be as large as engineering or product permits. The area of the conductor 3 is not smaller than the area of the antenna 2. The conductor 3 is preferably a planar conductor, such as a circular or rectangular conductor, but may also be designed to be non-planar or irregular depending on the application and the adaptive mechanical structure. The thickness of the conductor should be larger than the skin depth of the electromagnetic wave of 13.56MHz, otherwise the radiation disturbance suppression and the anti-interference effect are reduced.

As to the material of the conductor 3. The conductor 3 is preferably made of metal or alloy material, and is low in cost and easy to process. Other materials may be used as long as they have good conductivity. The materials preferably used are: aluminum, copper, stainless steel, iron, and other plates or foils.

With respect to the grounding of the conductor 3. The conductor 3 may be connected to the reader power ground or signal ground, or to ground. The conductor 3 may also be completely independent and not electrically connected to the reader 1. The conductor 3 with large area can be used as a reference ground plane of high-frequency signals and provides a low-resistance loop for displacement current radiated by an electric field of the antenna 2, so that most of the electric field radiation of the antenna 2 exists between the conductor 3 and the antenna 2, the radiation of the far-field electric field is greatly reduced, and the radiation disturbance is reduced. The effect of suppressing the radiation of the electric field is even more pronounced if the conductor 3 can be well grounded or connected to the signal ground/power ground of the reader 1.

Regarding the shape of the antenna 2. The antenna 2 is a loop coil antenna in which the total length of the single antenna coil is no more than 11m (half the wavelength of the electromagnetic wave of 13.56MHz in air). When the reader antenna 2 is other shapes than a loop, half of the maximum line size of the antenna (e.g., half of the diagonal of a rectangular antenna, half of the major axis of an elliptical antenna) may be used as a reference dimension for the distance between the conductor 3 and the antenna 2.

With respect to the position of the conductor 3. The placement of the conductor 3 is not limited to a single side of the antenna 2, and a double-side placement is more effective. When the single side of the antenna 2 is a working area, the conductor 3 is preferably placed on the opposite side of the working area, and the misreading of a non-working area can be reduced. The conductor 3 may also be placed on the same side of the operating area of the antenna 2. When both sides of the antenna 2 are the working area, the conductor 3 may be placed on one side or both sides outside the working area.

Regarding the communication standard adopted by NFC readers. The utility model discloses a NFC reads ware 1 can be suitable for each item communication standard that NFC used, and the operating frequency of this agreement is 13.56 MHz. The ISO15693 protocol belongs to the RFID category and does not belong to NFC, and although the operating frequency is 13.56MHz, the application scenarios and requirements of the two protocols are greatly different due to the requirement of the lowest operating field strength and the difference between the communication modulation and the communication speed with the NFC protocol. The minimum working field strength of ISO14443 is 1.5A/m, and the minimum working field strength of ISO15693 protocol is 0.15A/m, so that the reading distance of ISO15693 can reach 1m, the requirement of antenna transmitting power is much lower than that of ISO14443, the data transmission rate is also lower, therefore, too much radiation disturbance problem can not be generated, and the influence of conductors nearby the antenna on the antenna field strength is relatively small. Based on the above characteristics of ISO15693, it is often used in access control such as an access card, and the amount of information for reading an electronic tag is small. The NFC reading distance is generally less than 10cm, the NFC intelligent card is mainly applied to the fields of identity cards, passports, financial cards and the like, the information quantity of the read electronic tag intelligent card is large, the data encryption strength is high, and the security mechanism is complex.

To sum up, the utility model discloses a NFC reads ware 1 has increased a large tracts of land conductor 3 near its antenna 2, and antenna 2's far field electric field and magnetic field radiation all significantly reduce. According to the dual principle of antenna transmission and reception, the external interference received by the reader antenna 2 is greatly reduced, so that the anti-interference capability of the reader is effectively improved.

NFC detection device 10

Referring to fig. 2, an NFC detecting device 10 in the first embodiment of the present invention includes the above-mentioned NFC reader 1, and further includes a display device, a reminding alarm device, a network communication device, and the like (not shown in the figure). The utility model discloses a detection device can adopt common NFC detection device's structure among the prior art, for example, NFC detection device 10 includes identity detection device, article detection device, vehicle detection device etc.. For example, the NFC device 10 shown in fig. 2 is a side view of an identity detection device. The NFC detection device 10 shown in fig. 2 includes the above-described NFC reader 1. Wherein the conductor 3 of the NFC reader 1 is arranged parallel to the antenna 2 and the conductor 3 is placed at the opposite side of the operating range of the antenna 2.

Referring to fig. 3, the structure of an NFC device 10 in the second embodiment of the present invention is the same as that of the NFC device 10 in the first embodiment, except that the conductor 3 and the plane of the antenna 2 form an acute angle.

Referring to fig. 4, an NFC device 10 in a third embodiment of the present invention has the same structure as the NFC device 10 in the first embodiment, but includes two conductors 3, an antenna 2 disposed between the two conductors 3, and each conductor 3 is disposed in parallel with the antenna 2.

Referring to fig. 5, an NFC device 10 according to a fourth embodiment of the present invention has the same structure as the NFC device 10 according to the third embodiment, except that one of the two conductors 3 forms an acute angle with the plane of the antenna 2.

Referring to fig. 6, an NFC device 10 in a fifth embodiment of the present invention has the same structure as the NFC device 10 in the first embodiment, except that a conductor 3 is disposed between two antennas 2, and each antenna 2 is disposed in parallel with the conductor 3.

Referring to fig. 7, an NFC device 10 in a sixth embodiment of the present invention has the same structure as the NFC device 10 in the first embodiment, but includes two antennas 2 and two conductors 3, where the two antennas 2 are disposed between the two conductors 3, and each antenna 2 is disposed in parallel with the conductor 3. The operating ranges of the two antennas 2 may coincide or partially overlap. The two antennas 2 may be a transmitting antenna, a receiving antenna, or a transceiving duplex antenna, respectively. The two antennas 2 may also be array antennas. There may or may not be an electrical connection between the two conductors 3.

Referring to fig. 8, an NFC device 10 in the seventh embodiment of the present invention has the same structure as the NFC device 10 in the sixth embodiment, except that the NFC device 10 is a channel, and two conductors 3 are respectively disposed on the left and right sides of the channel. Furthermore, one conductor 3 is also provided below the channel, or one conductor 3 is provided above the channel (only the case of being provided below is shown in the figure).

Referring to fig. 9, an NFC device 10 according to an eighth embodiment of the present invention has the same structure as the NFC device 10 according to the seventh embodiment, except that a conductor 3 is disposed on each of the left and right sides of the channel in the channel of the NFC device 10, and a conductor 3 is disposed above and below the channel.

NFC detection system 100

The present invention further includes an NFC detection system 100, including one of the NFC detection devices 10 in the above embodiments. NFC detection system 100 also includes an electronic label smart card. The electronic tag smart card can be a radio frequency encryption card (ID card), a radio frequency storage card (non-contact IC card), a radio frequency CPU card and other various electronic tag smart cards. The NFC detection device 10 is used for carrying out contactless communication with an electronic tag smart card through space coupling, and functions of identity detection, article detection or vehicle detection and the like are achieved.

The NFC detection system 100 may include one NFC detection device 10, or may include a plurality of NFC detection devices 10.

Referring to fig. 10, an NFC detection system 100 in a ninth embodiment of the present invention includes a plurality of NFC detection devices 10 having the same structure as the first embodiment and a plurality of electronic tag smart cards (not shown in the figure). Only in this embodiment the conductor 3 of the respective NFC detection device 10 is replaced by a large area conductor 3. Because conductor 3 of large tracts of land sets up the one side at each antenna 2 of NFC detection device 10, can significantly reduce the radiation harassment of each antenna, simultaneously, can also reduce the interference between each antenna 2, improve the isolation between each antenna to improve the density that the card effect of reading and antenna were arranged.

Antenna tuning method

Due to the fact that a large-area conductor is additionally arranged near the reader antenna, the distribution and the field intensity of an electromagnetic field generated by the reader antenna are influenced, and therefore the distance and the effect of NFC are influenced. When being in the utility model discloses an increase conductor 3 back in NFC reader, detection device or the detecting system, the tuning of original antenna 2 will be detuned, and the impedance will mismatch. For this purpose, the antenna 2 should be retuned to match the impedance again. Also, the Q value of the coil of the antenna 2 may need to be adjusted after the conductor 3 is increased.

Experimental verification

To the utility model discloses a NFC reads ware, detection device or detecting system, increases behind the conductor, and original antenna magnetic field distribution can change, and field intensity can weaken. By reasonably adjusting the distance between the conductor and the antenna, the working distance and the range of the antenna can be not obviously changed, and the acceptable degree of the product can be achieved. Referring to fig. 11, it can be verified by the following experiment:

a circular antenna 2 and a circular aluminum conductor 3 are used, wherein the area of the conductor 3 is 4 times larger than that of the antenna 2, the thickness of the conductor 3 is 1mm, the antenna 2 and the conductor 3 are parallel to each other and project from the center of the plane to be superposed, the conductor 3 is arranged on the left side of the antenna 2, and the right side of the antenna 2 is the working area of the antenna. And taking the height of the right center of the antenna 2 as a radius R as a measuring point, adjusting the distance between the conductor 3 and the antenna 2, and measuring the field intensity of the coil of the antenna 2.

When the conductor 3 is at a distance from the antenna 2 equal to the antenna radius R, the field strength at the measuring point does not drop by more than 20%. The operating range of the antenna is not greatly affected at this time.

When the conductor 3 is at a distance 1/2 from the antenna 2 equal to the radius of the antenna, the field strength at the measuring point does not drop more than 40%. The operating range of the antenna is somewhat affected at this time, but is acceptable.

When the conductor 3 is at a distance 1/10 from the antenna 2 equal to the radius of the antenna, the field strength drops by more than 95% at the measuring point. The antenna can hardly function normally at this time.

The utility model discloses a NFC reads ware, check out test set and detecting system, working distance is far away (> 10cm), and the radiation disturbance is low, and the interference killing feature is strong, simultaneously, is fit for deploying in NFC check out test set and detecting system, and is with low costs, workable.

The drawings of the utility model are only schematic structural diagrams and are not used for measuring the size and the proportional relation of the antenna 2 and the conductor 3. The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims (19)

1. A low-radiation anti-interference remote near-field communication reader, comprising an antenna (2), and a signal processing unit connected to the antenna (2), characterized in that: the antenna is characterized in that at least one large-area conductor (3) is arranged near the antenna (2), the conductor (3) is a planar conductor, the two planes of the antenna (2) and the conductor (3) are parallel to each other or form an acute angle with each other, the area of the conductor (3) is larger than that of the antenna (2), the thickness of the conductor (3) is larger than the skin depth of electromagnetic waves corresponding to the working frequency of the reader, the distance from the center of the plane of the conductor (3) to the plane of the antenna (2) is larger than 1/4 times of the radius of the antenna (2) and smaller than 1/12 of the wavelength of the electromagnetic waves corresponding to the working frequency of the reader.

2. The reader according to claim 1, wherein the area of said conductor (3) is more than 4 times the area of said antenna (2).

3. The reader according to claim 1, wherein said antenna (2) is at a distance from said conductor (3) of between 1/4 and 1 times the radius of said antenna (2).

4. A reader according to claim 1, characterized in that the projection of the antenna (2) in the plane of the conductor (3) is close to the centre of the conductor (3) and does not extend beyond the extent of the conductor (3).

5. The reader according to claim 1, wherein the plane of said conductor (3) is circular or rectangular.

6. The reader according to claim 1, wherein said conductor (3) is a metal or alloy material.

7. The reader according to claim 6, wherein the material used for said conductor (3) is aluminum, copper, stainless steel, iron, or other plate or foil.

8. The reader according to claim 1, wherein the antenna (2) is a loop coil antenna, wherein the total length of the single antenna coil is no more than half the wavelength of the electromagnetic wave corresponding to the operating frequency of the reader.

9. The reader according to claim 1, wherein said conductor (3) is connected to a power ground or a signal ground of said reader, or to a ground.

10. The reader according to claim 1, wherein said conductor (3) is not electrically connected to said antenna (2).

11. The reader according to claim 1, wherein said conductors (3) are arranged on both sides of said antenna (2).

12. A reader according to claim 1, characterized in that when one side of the antenna (2) is the active area, the conductor (3) is arranged on the other side of the antenna (2).

13. A reader according to claim 1, characterized in that the conductors (3) are arranged on both sides of the antenna (2) when both sides of the antenna (2) are active areas.

14. The reader according to claim 1, characterized in that it uses IS014443 protocol, with an operating frequency of 13.56 MHz.

15. A near field communication detection device, characterized in that it comprises a reader according to any one of claims 1-14.

16. The detecting device according to claim 15, wherein the detecting device is a passage, one of said conductors (3) is disposed on each of the left and right sides of the passage, and one of said conductors (3) is disposed below or above the passage.

17. The detecting device according to claim 15, wherein the detecting device is a passage, one of said conductors (3) is provided on each of the left and right sides of the passage, and one of said conductors (3) is provided above and below the passage.

18. A near field communication detection system, characterized in that it comprises at least one detection device according to any one of claims 15 to 17, and also at least one electronic label smart card.

19. A detection system according to claim 18, characterized in that a large-area conductor (3) is arranged on one side of the plurality of detection means, the area of said conductor (3) being larger than the sum of the areas of said antennas (2) of said plurality of detection means.

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