CN114361778A - NFC antenna circuit, NFC antenna module and electronic equipment - Google Patents
NFC antenna circuit, NFC antenna module and electronic equipment Download PDFInfo
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Abstract
The invention discloses an NFC antenna circuit, an NFC antenna assembly and electronic equipment, wherein the NFC antenna circuit comprises: an NFC antenna comprising a first antenna segment and a second antenna segment; the antenna matching circuit is connected with the first antenna section and used for realizing impedance matching with the NFC antenna; the receiving circuit is connected with the second antenna section of the NFC antenna and used for converting the wireless data signals received by the NFC antenna into electric signals; the first isolation device is arranged between the first antenna section and the second antenna section in series; and the second isolation device is arranged between the receiving circuit and the second antenna section in series. The method solves the problem of reduced yield of the PCB antenna caused by antenna short circuit in the PCB manufacturing process, and is beneficial to improving the manufacturing efficiency of the NFC antenna and the yield of the NFC antenna.
Description
Technical Field
The present invention relates to the field of electronic circuit technologies, and in particular, to an NFC antenna circuit, an NFC antenna assembly, and an electronic device.
Background
In the production process of the PCB, due to reasons such as manufacturing procedures, when the antenna arranged on the PCB is in a thin line width and a short line distance, a part of lines adjacent to the antenna are short-circuited with a certain probability to cause antenna failure, and therefore, the antenna needs to be subjected to a flying probe (short circuit) test. The antenna is manufactured on the printed circuit board, because the matching circuit antenna of the antenna physically belongs to the same network, after the antenna is manufactured on the PCB, the antenna cannot be subjected to flying probe testing, the electronic element of the NFC antenna assembly needs to be arranged on the PCB, and the test can be performed after program burning, unnecessary loss can be caused at the moment, the material waste is serious, the test is complex, and the manufacturing efficiency and the yield of the NFC antenna assembly are reduced.
Disclosure of Invention
The invention mainly aims to provide an NFC antenna circuit, an NFC antenna assembly and electronic equipment, and aims to solve the problem that the yield of PCB printed board antennas is reduced due to antenna short circuit caused in the PCB manufacturing process.
To achieve the above object, the present invention provides an NFC antenna circuit, including:
an NFC antenna comprising a first antenna segment and a second antenna segment;
the antenna matching circuit is connected with the first antenna section and used for realizing impedance matching with the NFC antenna;
a receiving circuit connected to the second antenna segment of the NFC antenna for converting the generated wireless data signal received by the NFC antenna into an electrical signal;
a first isolation device disposed in series between the first antenna segment and the second antenna segment;
a second isolation device disposed in series between the receive circuit and the second antenna segment.
Optionally, the first isolation device is a zero ohm resistor;
and/or the second isolation device is a zero ohm resistor.
Optionally, the NFC antenna circuit further includes:
a signal transmitting terminal;
and the EMC filter circuit is arranged between the signal sending end and the antenna matching circuit in series.
Optionally, the signal transmitting end includes a first signal transmitting end and a second signal transmitting end; the EMC filter circuit comprises a first inductor, a second inductor, a first capacitor and a second capacitor, one end of the first inductor is connected with the first signal sending end, and the other end of the first inductor is connected with the antenna matching circuit; one end of the second inductor is connected with the second signal sending end, and the other end of the second inductor is connected with the antenna matching circuit; the first capacitor is arranged between the first inductor and the ground in series; the second capacitor is arranged between the second inductor and the ground in series.
Optionally, the antenna matching circuit includes:
the third capacitor is arranged between the EMC filter circuit and the first antenna section in series; the fourth capacitor is arranged in series between the EMC filter circuit and the second antenna section; the fifth capacitor is arranged between the third capacitor and the ground in series; the sixth capacitor is arranged between the fourth capacitor and the ground in series.
Optionally, the NFC antenna circuit further includes a signal receiving terminal and a bias voltage input terminal;
the receiving circuit comprises a first resistor, a second resistor and a seventh capacitor, one end of the first resistor is connected with the bias voltage input end, the other end of the first resistor is connected with the signal receiving end and one end of the second resistor, the other end of the second resistor is connected with one end of the seventh capacitor, and the other end of the seventh capacitor is connected with the second isolating device.
Optionally, an operating frequency of the NFC antenna circuit is 13.56 MHZ.
The invention further provides an NFC antenna assembly which comprises an NFC chip and the NFC antenna circuit, wherein the NFC chip is electrically connected with the NFC antenna circuit.
Optionally, the NFC antenna assembly further comprises:
the NFC antenna circuit and the NFC chip are arranged on the PCB.
The invention also proposes an electronic device comprising an NFC antenna circuit as described above, or comprising an NFC antenna assembly as described above.
The NFC antenna is divided into a first antenna section and a second antenna section, so that the first antenna section is connected to an antenna matching circuit used for achieving impedance matching with the NFC antenna, the second antenna section is connected to a receiving circuit used for converting wireless data signals received by the NFC antenna into electric signals, the NFC antenna is further provided with a first isolation device which is serially arranged between the first antenna section and the second antenna section, and the first antenna section is connected to a network formed by the antenna matching circuit and the second antenna section is connected to a network formed by the receiving circuit under the isolation of a second isolation device which is serially arranged between the receiving circuit and the second antenna section, namely the first antenna section and the second antenna section belong to two different networks. The NFC antenna is formed on the PCB, or the NFC antenna is manufactured, the short-circuit testing device can be connected to complete the short-circuit test of the NFC antenna.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a schematic circuit diagram of an NFC antenna circuit according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an NFC antenna element according to an embodiment of the present invention;
fig. 3 is a functional block diagram of an NFC antenna assembly according to an embodiment of the present invention.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) |
| 100 | |
50 | |
| 200 | |
60 | |
| 10 | NFC antenna | R1 | A first resistor |
| 11 | First antenna segment | R2 | |
| 12 | Second antenna segment | C1～C7 | First to |
| 20 | First isolation device | L1 | |
| 30 | Second isolation device | L2 | |
| 40 | Receiving circuit | U1 | NFC chip |
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.
In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
The invention provides an NFC antenna circuit.
Referring to fig. 1 to 3, in an embodiment of the present invention, the NFC antenna circuit 200 includes:
an NFC antenna 10 including a first antenna segment 11 (indicated by a dotted line in the figure) and a second antenna segment 12 (indicated by a solid line in the figure);
an antenna matching circuit 50 connected to the first antenna segment 11, for implementing impedance matching with the NFC antenna 10;
a receiving circuit 40, a second antenna segment 12 connected to the NFC antenna 10, configured to convert the generated wireless data signal received by the NFC antenna 10 into an electrical signal;
a first isolation device 20 disposed in series between the first antenna segment 11 and the second antenna segment 12;
a second isolation device 30 disposed in series between the receive circuit 40 and the second antenna segment 12.
In this embodiment, the NFC antenna circuit 200 is connected to the NFC chip U1, and transmits data from the NFC chip U1 through an electromagnetic field of radio frequency, so as to automatically identify information stored in the NFC chip U1. The NFC antenna circuit 200 may have a passive topology, and the NFC chip U1 may obtain energy from an electromagnetic field emitted by an external device when recognizing the NFC antenna circuit, without consuming energy of an electronic device to which the antenna circuit is applied. The electronic device applied to the NFC antenna circuit 200 of this embodiment may be used as a transponder or a reader, and when used as a transponder, may have a unique electronic code, and the unique electronic code is identified by an external device, thereby implementing card swiping, door access, mobile phone payment, and the like. When the device is used as a reader, data of other external devices can be read, and short-distance data transmission, such as transmission of audio, images and the like, is realized. The main operating frequency of the NFC device may be a high frequency of 13.56MHZ, among others.
The antenna matching circuit 50 is configured to perform impedance matching with the NFC antenna 10 when the frequency of the NFC antenna 10 is within the operating frequency range, thereby increasing the effective bandwidth of the NFC antenna 10. The antenna matching circuit 50 is connected between the NFC antenna 10 and the NFC chip U1. The antenna matching circuit 50 may adjust the resonant frequency of the antenna and match the impedance in the direction toward the NFC chip U1 with the impedance in the direction toward the antenna so as to increase the communication efficiency of the NFC antenna assembly. The operating frequency range may be an operating frequency range in which the NFC antenna 10 is required to be located when performing NFC sensing (e.g., payment, unlocking a door, etc.), such as about 13 MHz. The receiving circuit 40 is used for converting the wireless data signal into an electrical signal
The NFC antenna 10 is used for transmitting the wireless data signals with external NFC equipment through near field coupling, the NFC antenna 10 receives the wireless data signals from the outside and converts the wireless data signals into electric signals, the electric signals are transmitted to the receiving circuit 40 and then transmitted to the NFC chip U1 through the receiving circuit 40, connection is established with the external NFC equipment through the near field coupling, and the signals are transmitted. The NFC antenna 10 transmits electromagnetic signals with external NFC devices, such as mobile terminals, smart cards, and the like, through near field coupling, and the NFC antenna circuit 200 transmits and receives wireless data signals and performs corresponding conditioning, such as impedance matching and the like.
The NFC antenna 10 of this embodiment may be a planar antenna, and may be manufactured by using one of a physical vapor deposition process, a chemical vapor deposition process, an evaporation process, a sputtering process, an electroplating process, or a chemical plating process. The NFC antenna 10 may be formed on the PCB 100 by a printed circuit wiring process, the NFC antenna 10 may be directly formed on the PCB 100 by processes such as copper-clad plating and etching, the NFC antenna 10 may also be implemented by an FPC antenna, the FPC antenna may be adhered to the PCB 100 by an adhesive material, or the FPC antenna may be embedded in the PCB 100 by an embedded method, or the antenna pattern of the NFC antenna 10 may be formed by pressing onto the PCB 100 by other processes. When the NFC antenna 10 is disposed on the electronic control board, the NFC antenna may be implemented by forming a trace of the antenna on the PCB circuit board 100 in a PCB circuit wiring manner. The thickness, size and shape of the PCB 100 may be set according to the actual application product and the application environment, so as to meet different application requirements. In one embodiment, the PCB circuit board 100 may be square in shape, such as rectangular or square. The NFC antenna 10 may also be made of ferrite material with interference resistance.
The NFC antenna 10 is divided into two antenna segments in this embodiment, that is, the first antenna segment 11 and the second antenna segment 12 are spaced apart from each other, and there is no direct connection between the two antenna segments. The two antenna segments have two ends, which are respectively marked as a first end and a second end, wherein the first end of the first antenna segment 11 is connected with the antenna matching circuit 50, and the second end of the first antenna is connected with one end of the first isolation device 20; the first end of the second antenna segment 12 is connected to the receiving circuit 40, the second end of the second antenna is connected to the other end of the first isolation device 20, and the other end of the first isolation device 20 is also connected to the ground terminal of the NFC antenna circuit 200, that is, the second end of the second antenna segment 12 is electrically connected to the first antenna under the isolation effect of the first isolation device 20.
When the NFC antenna circuit 200 is in operation, for example, the NFC antenna circuit 200 receives a wireless data signal input from the outside through the NFC antenna 10, specifically, the second antenna segment 12 receives electromagnetic energy, and outputs the electromagnetic energy to the receiving circuit 40 through the second antenna segment 12 and the second isolation device 30, and the receiving circuit 40 converts the wireless data signal into an electrical signal and outputs the electrical signal to the NFC chip U1. When the NFC antenna circuit 200 transmits a wireless data signal to the outside through the NFC antenna 10, the first antenna segment 11 and the second antenna segment 12 convert the electrical signal into the wireless data signal, radiate electromagnetic energy to the outside, and the electromagnetic energy is radiated under the action of the NFC antenna 10, specifically, the electrical signal is output to the first antenna segment 11 through the antenna matching circuit 50 and the first isolation device 20, and is radiated by the first antenna segment 11.
Under the isolation of the first isolation device 20 and the second isolation device 30, the first antenna segment 11 is connected to the network formed with the antenna matching circuit 50, the second antenna segment 12 is connected to the network formed with the receiving circuit 40, and the receiving circuit 40 and the antenna matching circuit 50 belong to two different networks. When the NFC antenna 10 is manufactured, the first antenna segment 11 and the second antenna segment 12 are separated from each other when the antenna trace is manufactured, so that physical isolation is performed, and under the isolation of the first isolation device 20 and the second isolation device 30, a flying probe test is performed during PCB production, that is, during a short circuit test, whether there is a short circuit between adjacent antennas can be tested.
In practical applications, the first antenna segment 11 and the second antenna segment 12 may be tested separately by using a testing device for performing a short circuit test. Specifically, the first antenna segment 11 may be connected to a power supply circuit constructed in a short-circuit testing device to supply a current to the first antenna segment 11, a current loop is formed between the first antenna segment 11 and the short-circuit testing device, and then two test points, such as test probes, are connected to the first antenna segment 11 and the second antenna segment 12, it can be understood that, when the second antenna segment 12 is not connected to the power supply circuit constructed in the short-circuit testing device, the current loop cannot be formed between the second antenna segment 12 and the short-circuit testing device, so that normally, the first antenna segment 11 and the second antenna segment 12 are disconnected, and if the short-circuit testing device detects that electrical signals exist in the first antenna segment 11 and the second antenna segment 12, it may be determined that the first antenna segment 11 and the second antenna segment 12 are adhered to each other, and a short-circuit point exists. On the contrary, if the short circuit testing device detects that the first antenna segment 11 and the second antenna segment 12 have no electric signal, it can be determined that no adhesion occurs between the first antenna segment 11 and the second antenna segment 12, and no short circuit point exists. Similarly, the second antenna segment 12 may be connected to a power supply circuit constructed in the short circuit testing device to supply current to the first antenna segment 11, a current loop is formed between the second antenna segment 12 and the short circuit testing device, and then two testing points, such as testing probes, are connected to the first antenna segment 11 and the second antenna segment 12, if the short circuit testing device detects that electrical signals exist in the first antenna segment 11 and the second antenna segment 12, it may be determined that adhesion occurs between the first antenna segment 11 and the second antenna segment 12, and a short circuit point exists. On the contrary, if the short circuit testing device detects that the first antenna segment 11 and the second antenna segment 12 have no electric signal, it can be determined that no adhesion occurs between the first antenna segment 11 and the second antenna segment 12, and no short circuit point exists.
The NFC antenna 10 is divided into a first antenna segment 11 and a second antenna segment 12, so that the first antenna segment 11 is connected to an antenna matching circuit 50 used for achieving impedance matching with the NFC antenna 10, the second antenna segment 12 is connected to a receiving circuit 40 used for converting a generated wireless data signal received by the NFC antenna 10 into an electric signal, a first isolation device 20 is arranged between the first antenna segment 11 and the second antenna segment 12 in series, and the first antenna segment 11 is connected to a network formed by the antenna matching circuit 50 and the second antenna segment 12 is connected to a network formed by the receiving circuit 40 under the isolation of a second isolation device 30 arranged between the receiving circuit 40 and the second antenna segment 12 in series, namely the first antenna segment 11 and the second antenna segment 12 belong to two different networks. The NFC antenna 10 is formed on the PCB, or after the NFC antenna 10 is manufactured, the short circuit testing device can be connected to complete the short circuit test of the NFC antenna 10.
Referring to fig. 1-3, in one embodiment, the first isolation device 20 is a zero ohm resistor;
and/or the second isolation device 30 is zero ohm resistance.
In this embodiment, the first isolation device 20 and the second isolation device 30 may both be implemented by zero-ohm resistors, and the two zero-ohm resistors may isolate the first antenna segment 11 and the second antenna segment 12 into two different networks, so as to physically isolate them, so that a flying probe test is performed during PCB production, that is, whether there is a short circuit between adjacent antennas can be tested during a short circuit test.
Referring to fig. 1 to 3, in an embodiment, the signal transmitting end includes a first signal transmitting end TX1 and a second signal transmitting end TX 2; the EMC filter circuit 60 includes a first inductor L1, a second inductor L2, a first capacitor C1 and a second capacitor C2, one end of the first inductor L1 is connected to the first signal transmitting terminal TX1, and the other end of the first inductor L1 is connected to the antenna matching circuit 50; one end of the second inductor L2 is connected to the second signal transmitting terminal TX2, and the other end of the second inductor L2 is connected to the antenna matching circuit 50; the first capacitor C1 is arranged in series between the first inductor L1 and ground; the second capacitor C2 is serially disposed between the second inductor L2 and ground.
In this embodiment, the first signal transmitting terminal TX1 and the second signal transmitting terminal TX2 may be connected to two transmitting terminals of the NFC chip U1, and the two transmitting terminals output equal-amplitude and opposite-phase differential signals to drive the antenna to operate. The first inductor L1 and the first capacitor C1 form a low-pass filter circuit, and the second inductor L2 and the second capacitor C2 form another low-pass filter circuit.
Referring to fig. 1 to 3, in an embodiment, the antenna matching circuit 50 includes:
a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6, wherein the third capacitor C3 is arranged in series between the EMC filter circuit 60 and the first antenna segment 11; the fourth capacitance C4 is arranged in series between the EMC filter circuit 60 and the second antenna segment 12; the fifth capacitor C5 is arranged in series between the third capacitor C3 and ground; the sixth capacitor C6 is serially disposed between the fourth capacitor C4 and ground.
In this embodiment, the third capacitor C3 and the fourth capacitor C4 are series capacitors, and the fifth capacitor C5 and the sixth capacitor C6 are parallel capacitors, so that in practical applications, the internal resistance of the NFC receiving antenna can be measured through impedance, the capacitive reactance and the phase deviation of the antenna matching circuit 50 are measured through a network analyzer, and the capacitance values of the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5 and the sixth capacitor C6 are designed and adjusted, so that the internal resistance of the NFC antenna is consistent with the impedance of the antenna matching circuit 50, and the impedance provided by the antenna matching circuit 50 can be matched with the NFC antenna.
Referring to fig. 1 to 3, in an embodiment, the NFC antenna component further includes a signal receiving terminal RX and a bias voltage input terminal VMID;
the receiving circuit 40 includes a first resistor R1, a second resistor R2, and a seventh capacitor C7, one end of the first resistor R1 is connected to the bias voltage input terminal VMID, the other end of the first resistor R1 is interconnected with the signal receiving terminal RX and one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the seventh capacitor C7, and the other end of the seventh capacitor C7 is connected to the second isolating device 30.
In this embodiment, the first resistor R1 is used as a voltage divider and disposed between the signal receiving terminal RX and the bias voltage input terminal VMID, and the bias voltage inputted from the bias voltage input terminal VMID by the first resistor R1 can increase the voltage driving of the signal receiving terminal RX. The NFC antenna may convert a wireless data signal and an interference signal received from the outside into electrical signals, output the electrical signals to the seventh capacitor C7 and the second resistor R2 of the receiving circuit 40, and transmit the electrical signals to the NFC chip U1 through the second resistor R2 under the coupling and filtering effects of the seventh capacitor C7.
The invention further provides an NFC antenna assembly, which includes an NFC chip U1 and the NFC antenna circuit 200 as described above, where the NFC chip U1 is electrically connected to the NFC antenna circuit 200.
The detailed structure of the NFC antenna circuit 200 may refer to the above embodiments, and is not described herein again; it can be understood that, because the NFC antenna component of the present invention uses the NFC antenna circuit, the embodiment of the NFC antenna component of the present invention includes all technical solutions of all embodiments of the NFC antenna circuit, and the achieved technical effects are also completely the same, and are not described herein again.
Referring to fig. 1 to 3, in this embodiment, the NFC antenna circuit 200 may perform impedance matching and filtering on a wireless data signal, and debug a resonant frequency and an input impedance of an antenna. The NFC chip U1 is a chip with mutual communication function and calculation function, and can complete corresponding NFC function service according to the NFC chip U1. When the NFC chip U1 is applied to an electronic device, information interaction with a target device may be performed through the NFC antenna circuit 200. The NFC chip U1 may be used to implement a card mode execution function, for example, when replacing functions such as a bus card, a store card swipe, an access control, and the like, the target device in the present invention is a card reader. When the target device is a card reader, the NFC chip U1 sends authentication information to the card reader through a communication link, and receives an authentication result response sent by the card reader, so as to execute a corresponding card function after the authentication is passed. The NFC chip U1 may also be used for point-to-point data transmission between electronic devices, to implement short-distance data transmission with a target device, such as data exchange between two electronic devices or music file exchange, and may also be applied to NFC bluetooth devices, such as a bluetooth headset, a smart band, and the like.
The NFC chip U1 is integrated with a main control chip and an NFC read-write chip, an NFC algorithm is preset in the main control chip, the main control chip communicates with the NFC read-write chip, when the NFC read-write chip is connected with an external NFC device through an NFC antenna circuit 20010, the NFC read-write chip outputs a connection signal to the main control chip, so that the main control chip controls and responds to received information, the main control chip can also output a control signal to the NFC read-write chip according to the connection signal fed back by the NFC read-write chip for information processing, such as outputting a reset signal, an initialization signal, a read-write signal, a switching signal and the like, based on the NFC antenna circuit 200, the work modes of the NFC chip U1, which can be carried out by the external NFC device, can include but are not limited to a read-write mode, a point-to-point transmission mode and a smart card mode. Specifically, the NFC antenna circuit 200 realizes mutual wireless data signal communication between the NFC chip U1 and an external NFC device, the NFC chip U1 feeds back a connection signal to the main control chip when establishing connection with the external NFC device, and the main control chip outputs a control signal to the NFC read-write chip according to the connection signal fed back by the NFC read-write chip, so as to control the NFC read-write chip to perform read-write operation on a wireless data signal, thereby realizing an NFC function between the NFC circuit and the external device.
The NFC chip U1 has two signal transmitting terminals TX1 and TX2, a signal receiving terminal RX and a bias voltage output terminal VMIND, and a ground terminal TVSS, the two signal transmitting terminals TX1 and TX2 are connected to two input terminals of the EMC filter circuit 60 in the NFC antenna circuit 200 in a one-to-one correspondence, the signal receiving terminal RX and the bias voltage output terminal VMIND are connected to the signal receiving terminal RX and the bias voltage output terminal VMIND of the receiving circuit 40, and the ground terminal TVSS is used for grounding. The NFC chip U1 is connected to the NFC antenna circuit 200 through two signal transmitting terminals TX1, TX2 and a signal receiving terminal RX, and exchanges wireless data signals to implement wireless data signal transmission or stop transmission.
In some embodiments, the NFC antenna assembly further has a crystal oscillator (not shown) for providing a clock reference for the NFC chip U1, while the chip has high output power, so that the DC/DC booster becomes an unnecessary external component, which helps to save component cost and circuit board space.
Referring to fig. 1-3, in an embodiment, the NFC antenna assembly further includes:
the PCB circuit board 100, the NFC antenna circuit 200 and the NFC chip U1 are disposed on the PCB circuit board 100.
In this embodiment, both the NFC chip U1 and the NFC antenna circuit 200 are disposed on the PCB circuit board 100, and specifically, an antenna mounting area and a circuit mounting area are formed on the PCB circuit board 100, and the antenna mounting area is disposed around the circuit mounting area; the NFC antenna 10 in the NFC antenna circuit 200 is implemented by using a loop antenna, and a first loop antenna segment and a second loop antenna segment in the loop NFC antenna 10 are disposed in the antenna mounting area by using a two-wire parallel winding process; the antenna matching circuit 50, the receiving circuit 40, the NFC chip U1, the first isolation device 20, and the second isolation device 30 in the NFC antenna circuit 200 are all disposed on the circuit mounting region. The first antenna segment 11 and the second antenna segment 12 are annularly disposed on the periphery of the PCB 100, the annular region formed by the annular NFC antenna 10 can be used as a circuit mounting region of the NFC antenna assembly, that is, the electronic element of the NFC antenna assembly is mounted in the annular region formed by the annular NFC antenna 10, and PCB printing is performed in the annular region, so as to form a circuit wiring layer for mounting the antenna matching circuit 50, the receiving circuit 40, the first isolation device 20, and the second isolation device 30, and the electronic element is mounted on a pad corresponding to the circuit wiring layer by using a chip mounter or the like, so that a current loop of the antenna matching circuit 50, the receiving circuit 40, the first isolation device 20, and the second isolation device 30 can be formed.
A plurality of conductive vias are arranged on the PCB 100 to electrically connect the first antenna segment 11 with the first isolation device 20 and the antenna matching circuit 50 through the conductive vias; and the number of the first and second groups,
the second antenna segment 12 and the second isolation device 30 are electrically connected through the conductive via.
In this embodiment, the PCB circuit board 100 has two opposite side surfaces, namely a first side surface and a second side surface, and the receiving circuit 40, the antenna matching circuit 50, the EMC filter circuit 60, the NFC chip U1, and the like in the NFC antenna circuit may be disposed on one side surface of the PCB circuit board 100, or disposed on two opposite side surfaces of the PCB circuit board 100. In order to reduce the use of the binding wire and the flying wire, the present embodiment provides a plurality of conductive vias on the PCB circuit board 100, so that after the first antenna segment 11 and the second antenna segment 12 in the loop NFC antenna 10 belong to two different networks, the conductive vias and the circuit wiring can be electrically connected to the electronic components disposed in the loop mounting area.
It can be understood that, set up NFC chip U1 in PCB circuit board 100 back, still need carry out the procedure to NFC chip U1 and burn, later can also carry out product function test to the NFC antenna module, compare in the NFC antenna that makes at the printed circuit board and the matching circuit of antenna belong to same network in physics, if there is the short circuit condition, make PCB printed circuit board NFC antenna back can not directly carry out the flying probe test, also can't test out the condition of inside short circuit in the antenna, can only test when product function test, PCB has carried out SMT paster and software burn this moment, can cause unnecessary loss. The invention can detect whether the short circuit exists or not when the flying probe test is carried out, and can remove the PCB with the bad antenna, so that the PCB with the normal antenna can enter the steps of electronic element surface mounting, program burning and the like. The PCB antenna optimized by the invention greatly reduces the resource waste of the surface mounting of components and the complexity of testing which are possibly caused during processing, and can also reduce the testing of the antenna.
The invention also proposes an electronic device comprising an NFC antenna circuit as described above, or comprising an NFC antenna assembly as described above. The detailed structure of the NFC antenna circuit and the NFC antenna element can refer to the above embodiments, which are not described herein again; it can be understood that, because the NFC antenna circuit and the NFC antenna assembly are used in the electronic device of the present invention, embodiments of the electronic device of the present invention include all technical solutions of all embodiments of the NFC antenna circuit and the NFC antenna assembly, and the achieved technical effects are also completely the same, and are not described herein again.
The mobile terminal can be a smart phone, a computer, a multimedia player, an electronic reader, a wearable device and the like.
The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. An NFC antenna circuit, wherein the NFC antenna circuit comprises:
an NFC antenna comprising a first antenna segment and a second antenna segment;
the antenna matching circuit is connected with the first antenna section and used for realizing impedance matching with the NFC antenna;
a receiving circuit connected to the second antenna segment of the NFC antenna for converting the generated wireless data signal received by the NFC antenna into an electrical signal;
a first isolation device disposed in series between the first antenna segment and the second antenna segment;
a second isolation device disposed in series between the receive circuit and the second antenna segment.
2. The NFC antenna circuit of claim 1, wherein the first isolation device is a zero ohm resistor;
and/or the second isolation device is a zero ohm resistor.
3. The NFC antenna circuit of claim 1, further comprising:
a signal transmitting terminal;
and the EMC filter circuit is arranged between the signal sending end and the antenna matching circuit in series.
4. The NFC antenna circuit of claim 3, wherein the signal transmitting end includes a first signal transmitting end and a second signal transmitting end; the EMC filter circuit comprises a first inductor, a second inductor, a first capacitor and a second capacitor, one end of the first inductor is connected with the first signal sending end, and the other end of the first inductor is connected with the antenna matching circuit; one end of the second inductor is connected with the second signal sending end, and the other end of the second inductor is connected with the antenna matching circuit; the first capacitor is arranged between the first inductor and the ground in series; the second capacitor is arranged between the second inductor and the ground in series.
5. The NFC antenna circuit of claim 3, wherein the antenna matching circuit comprises:
the third capacitor is arranged between the EMC filter circuit and the first antenna section in series; the fourth capacitor is arranged in series between the EMC filter circuit and the second antenna section; the fifth capacitor is arranged between the third capacitor and the ground in series; the sixth capacitor is arranged between the fourth capacitor and the ground in series.
6. The NFC antenna circuit of claim 1, further comprising a signal receiving terminal and a bias voltage input terminal;
the receiving circuit comprises a first resistor, a second resistor and a seventh capacitor, one end of the first resistor is connected with the bias voltage input end, the other end of the first resistor is connected with the signal receiving end and one end of the second resistor, the other end of the second resistor is connected with one end of the seventh capacitor, and the other end of the seventh capacitor is connected with the second isolating device.
7. An NFC antenna circuit according to any one of claims 1 to 6, wherein the operating frequency of the NFC antenna circuit is 13.56 MHz.
8. An NFC antenna assembly comprising an NFC chip and an NFC antenna circuit according to any of claims 1 to 7, the NFC chip being electrically connected to the NFC antenna circuit.
9. The NFC antenna assembly of claim 8, further comprising:
the NFC antenna circuit and the NFC chip are arranged on the PCB.
10. An electronic device comprising an NFC antenna circuit according to any of claims 1 to 7 or an NFC antenna assembly according to any of claims 8 or 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111640658.5A CN114361778A (en) | 2021-12-28 | 2021-12-28 | NFC antenna circuit, NFC antenna module and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111640658.5A CN114361778A (en) | 2021-12-28 | 2021-12-28 | NFC antenna circuit, NFC antenna module and electronic equipment |
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| Publication Number | Publication Date |
|---|---|
| CN114361778A true CN114361778A (en) | 2022-04-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202111640658.5A Pending CN114361778A (en) | 2021-12-28 | 2021-12-28 | NFC antenna circuit, NFC antenna module and electronic equipment |
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