CN111279549B - Near field communication antenna system and terminal equipment - Google Patents
Near field communication antenna system and terminal equipment Download PDFInfo
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- CN111279549B CN111279549B CN201880069763.8A CN201880069763A CN111279549B CN 111279549 B CN111279549 B CN 111279549B CN 201880069763 A CN201880069763 A CN 201880069763A CN 111279549 B CN111279549 B CN 111279549B
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Abstract
The application provides a near field communication antenna system and terminal equipment relates to terminal technical field for increase the magnetic flux of NFC antenna, this near field communication antenna system is applied to terminal equipment, and this terminal equipment includes the metal frame, and this scheme includes: the NFC control module is arranged in the metal frame, the first resonant circuit is connected with a first feed-in point of the NFC control module, the second resonant circuit is connected with a second feed-in point of the NFC control module, and the grounding point is arranged in the metal frame; the NFC control module is used for generating a differential signal, and the first feed-in point is used for feeding the differential signal into the first resonant circuit; the first resonant circuit is also connected with the grounding point and is used for outputting the differential signal fed in by the first feed point to the grounding point; and the second resonant circuit is also connected with the grounding point and is used for feeding the differential signal input to the second resonant circuit through the grounding point into the NFC control module through the second feed-in point.
Description
Technical Field
The application relates to the technical field of terminals, in particular to a near field communication antenna system and terminal equipment.
Background
With the rapid development of terminal devices (e.g., mobile phones and tablet computers), more and more terminal devices support Near Field Communication (NFC) functions. The NFC function employs bidirectional identification and connection, and a terminal device supporting the NFC function (hereinafter, the terminal device supporting the NFC function is simply referred to as an NFC terminal device) has three functional modes: NFC terminal devices are used as identification devices (card reader mode), NFC terminal devices are used as read devices (card emulation, i.e. they can be used as integrated circuit cards (ICs) such as credit cards and public transport cards), and point-to-point (i.e. data interaction between multiple terminal devices, similar to bluetooth) communication applications between NFC terminal devices. Therefore, after the NFC function is turned on, the terminal device faces a lot of IC cards and point of sale (POS) devices, and the terminal device needs to have a certain compatibility due to the difference of resonance points between different IC cards and POS devices.
In a conventional technical solution, as shown in fig. 1, fig. 1 shows an NFC antenna structure in the conventional technical solution, which includes: a Flexible Printed Circuit (FPC) disposed in the metal frame 20 of the terminal device, and a coil 10 disposed on the FPC. Therefore, after the NFC terminal equipment starts the NFC function, the NFC antenna structure radiates an electric wave signal to perform signal transmission with the antenna of the POS machine, and communication is completed.
In addition, the metal frame of the terminal device can be used to realize the NFC antenna structure in the traditional technical scheme. For example, as shown in fig. 2, a Feed point (Feed, F) and a Ground point (Ground, G) are provided on a metal bezel 20 on the top of the terminal device, and a metal bezel 201 between the F point and the G point is used instead of the coil as shown in fig. 1 to constitute an NFC antenna.
However, the NFC antenna structure shown in fig. 1 occupies a large space inside the terminal device due to the large area of the coil 10, which increases the cost. The inductance value of the coil 10 is larger than that of the metal frame 20, but is not in an order of magnitude, and the resistance of the coil 10 and the resistance of the metal frame 20 are both smaller, generally in an order of magnitude, so the Q value of the coil 10 is larger, and the bandwidth of the NFC antenna is narrower. In the case of a terminal device using a metal back cover, the metal back cover may shield a portion of the antenna signal, which may result in poor performance of the NFC antenna. In addition, in fig. 2, the metal frame 201 is used instead of the coil, and some problems of poor compatibility with the POS device may occur in actual use.
Disclosure of Invention
The embodiment of the application provides a near field communication antenna system and terminal equipment, which are used for increasing the magnetic flux of an NFC antenna.
In a first aspect of the embodiments of the present application, a near field communication antenna system is provided, where the near field communication antenna system is applied to a terminal device, the terminal device includes a metal frame, and the antenna system includes: the NFC control module is arranged in the metal frame, the first resonant circuit and the second resonant circuit are connected with the NFC control module, and the grounding point is arranged in the metal frame; the metal frame is provided with at least two intervals positioned on different sides; the NFC control module is used for generating a differential signal; the first resonant circuit is further connected to the ground point, and is configured to output the differential signal output by the NFC control module to the ground point; the second resonant circuit is further connected to the ground point, and is configured to feed the differential signal input to the second resonant circuit via the ground point into the NFC control module.
Specifically, the NFC control module includes a first feed point and a second feed point, where the first feed point is configured to feed a differential signal into the first resonant circuit, and the second feed point is configured to feed the differential signal input to the second resonant circuit through the ground point into the NFC control module through the second feed point, or feed the differential signal into the second resonant circuit.
Correspondingly, the first resonant circuit is used for outputting the differential signal fed in by the first feed point to the grounding point; and the second resonant circuit is also connected with the grounding point and is used for feeding the differential signal input to the second resonant circuit through the grounding point into the NFC control module through the second feed-in point.
The application provides a near field communication antenna system, through set up the ground point in the metal frame to utilize and set up the first resonant circuit and the second resonant circuit in the metal frame and form a loop between ground point and the metal frame, the difference signal alright in order to form the backward flow along the loop of NFC control module output like this, thereby increased the circulation area of difference signal, increased the magnetic flux, thereby promote NFC's performance. In addition, the antenna system and other antennas provided by the application share the same structure, so that the degree of freedom is higher, and meanwhile, the influence on the realization and debugging of other antennas is reduced.
With reference to the first aspect, in a first possible implementation manner of the first aspect, the metal bezel is a frame body that is surrounded by a first bezel and a second bezel located above the first bezel and has at least two intervals, the first resonant circuit and the second resonant circuit are the same, and the first resonant circuit includes: the NFC control circuit comprises a first inductor, a first capacitor and a second capacitor, wherein a first end of the first inductor is connected with the second frame, a second end of the first inductor is connected with a first end of the first capacitor and a first end of the second capacitor, a second end of the first capacitor is grounded, and a second end of the second capacitor is connected with a first feed-in point of the NFC control module.
With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the ground point includes a first ground point and a second ground point, where the first ground point is connected to the first resonant circuit, the second ground point is connected to the second resonant circuit, the first ground point is located between the first resonant circuit and the second resonant circuit, the second resonant circuit is located between the first ground point and the second ground point, and the first ground point and the second ground point are connected to the metal bezel.
With reference to any one of the first aspect to the second possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, a phase shift unit is disposed between a second resonant circuit and the NFC control module, the second feed point is further configured to feed the differential signal into the second resonant circuit, and the phase shift unit is configured to convert a phase of the differential signal fed into the second resonant circuit by the second feed point, so that a phase of the differential signal fed into the second resonant circuit by the second feed point is the same as a phase of the differential signal fed into the first resonant circuit by the first feed point.
With reference to any one of the first aspect to the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the ground point includes a first ground point and a second node point, where the first ground point is connected to the first resonant circuit, the second ground point is connected to the second resonant circuit, and when the first ground point and the second ground point are connected to the metal bezel or the first ground point is connected to the metal bezel, the first ground point and the second ground point are located between the first resonant circuit and the second resonant circuit.
With reference to any one of the first aspect to the fourth possible implementation manner of the first aspect, in a fifth possible implementation manner of the first aspect, the first resonant circuit and the second resonant circuit are located between the first grounding point and the second grounding point, and the first grounding point and the second grounding point are connected to the metal bezel.
With reference to any one of the first aspect to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner of the first aspect, a second interval exists on a frame to which the first grounding point and the second grounding point are connected, in other words, the second interval is used for separating the first grounding point and the second grounding point.
With reference to any one of the first aspect to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner of the first aspect, the access point is connected to the second frame through a metal block elastic connecting piece or a lock screw.
In a second aspect of the embodiments of the present application, a terminal device is provided, where the terminal device includes a metal frame, at least two intervals located on different sides are provided on the metal frame, and the terminal device further includes: a near field communication antenna system as described in any one of the possible implementations of the first aspect to the first aspect above; a near field communication antenna system is used in the terminal equipment for transmitting and receiving signals.
Drawings
Fig. 1 is a schematic diagram of an NFC antenna structure provided in the prior art;
fig. 2 is a schematic diagram of another NFC antenna structure provided in the prior art;
fig. 3 is a schematic diagram of carrier modulation according to an embodiment of the present application;
fig. 4 is a first schematic structural diagram of a near field communication antenna system according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram of a near field communication antenna system according to an embodiment of the present application;
fig. 6 is a schematic structural diagram three of a near field communication antenna system according to an embodiment of the present application;
fig. 7 is a fourth schematic structural diagram of a near field communication antenna system according to an embodiment of the present application;
fig. 8 is a schematic structural diagram of a near field communication antenna system according to an embodiment of the present application;
fig. 9 is a sixth schematic structural diagram of a near field communication antenna system according to an embodiment of the present application;
fig. 10 is a seventh schematic structural diagram of a near field communication antenna system according to an embodiment of the present application;
fig. 11 is a schematic structural diagram eight of a near field communication antenna system according to an embodiment of the present application;
FIG. 12 is a first comparative illustration provided by an embodiment of the present application;
fig. 13 is a second comparative schematic diagram provided in the examples of the present application.
Detailed Description
Before describing a near field communication antenna system provided by the embodiment of the present invention, first, the principle of the embodiment of the present invention is described:
let the frequency of the modulation signal be omega0Carrier frequency of omegacSubcarrier frequency of omegasub. According to the fourier transform frequency shift characteristic that is the modulation theorem,
fourier transform frequency shift characteristics: if F (j ω) ═ F (t),
then
For the modulation process in NFC communication, as shown in fig. 3: firstly, the baseband signal is firstly aligned to the subcarrier omegasubModulating, modulating the modulated wave, and modulating the carrier signal omega again as a baseband signalc。
In FIG. 3,. omega.0For modulating the frequency of the signal, omegacIs the carrier signal frequency, omegasubFor subcarrier frequencies, in the NFC field, different standards (e.g. ISO 14443A, ISO 14443B and ISO15693) specify the carrier signal ωcThe working frequency is 13.56MHz, and subcarrier modulation technology is adopted. During the modulation, different subcarriers may be modulated with frequency offset (e.g., the allowable frequency offset is-7 KHz to +7 KHz). However, the different standards use different subcarrier frequencies, ISO 14443A and ISO 14443B, with 847.5KHz subcarrier frequency used, 423KHz subcarrier frequency used in ISO15693, 106Kbit/s bit rate required by ISO 14443A, 212Kbit/s bit rate required by ISO 14443B and 424Kbit/s bit rate required by ISO 15693. The terminal equipment is compatible with the above standards and needs to meet certain bandwidth requirements. Taking the bit rate of the baseband signal as 106Kbit/s as an example, the specified frequency is 13.56MHz, and because the subcarrier technology is adopted, the carriers are 12.71MHz (13.56 MHz-847.5 KHz) and 14.4MHz, respectively. Therefore, when the NFC antenna is in a normal operating state, the Bandwidth (BW) of the NFC antenna needs to include the bandwidth of two subcarriers. For example, the required bandwidth of the NFC antenna is: 2 x (847.5+106+7) KHz-1.92 MHz. When the rate is 424Kbit/s, BW 2 × (847.5+424+7) KHz 2.557MHz, that is, the terminal device needs to be compatible to the maximum bandwidth. Based on this, this application utilizes difference signal characteristics in NFC antenna communication from the antenna principle, introduces ground connection in the NFC antenna, increases the backward flow route to produce two at least backward flows, thereby produce two resonance and increase the bandwidth, make two backward flows in phase in addition, also increased the magnetic flux like this simultaneously, thereby improve the performance.
As shown in fig. 4, fig. 4 shows a near field communication antenna system provided by the present application, which is applied in a terminal device, the terminal device has a metal frame 30, and the antenna system includesComprises the following steps: a NFC control module (also referred to as an NFC chip) 40 disposed in the metal frame 30 and a first feed point F of the NFC control module 401A first resonant circuit 50 connected to the second feed point F of the NFC control module 402A second resonant circuit 60 connected to the first resonant circuit, and a ground point G disposed in the metal frame 30; the metal bezel 30 has at least two spaces (e.g., space a and space B shown in fig. 4) on different sides. The NFC control module 40 is configured to generate a differential signal, and the first feeding point F1For feeding a differential signal into the first resonant circuit 50, the first resonant circuit 50 being further connected to a ground point G for feeding the first feed point F1The fed differential signal is output to the ground point G. A second resonant circuit 60 connected to the ground point G for inputting the differential signal from the ground point G through a second feed point F2Is fed into the NFC control module 40 to form a loop.
First feed point F in the present application1The differential signal output by the NFC control module 40 may be fed into the first resonant circuit 50, or the differential signal input by the ground point G may be fed into the NFC control module 40.
Second feed point F2The differential signal output by the NFC control module 40 may be fed into the second resonant circuit 60, or the differential signal input by the ground point G may be fed into the NFC control module 40. Specifically, a first feed point F1And a second feed point F2Whether to input the differential signal into the NFC control module 40 or output the differential signal from the NFC control module 40 will be described below with reference to specific embodiments, and details are not described here.
It is understood that the first feeding point F in the present application1And a second feed point F2The NFC control module 40 may have a feeding point, or may have two feeding points fixed to the NFC control module 40 in other manners (for example, in a welding manner), which is not limited in the present application. As long as the first feed point F1The signal of the NFC control module can be ensured to access the first resonant circuit 50 and the second feed point F2The signal of the NFC control module 40 can be guaranteed to be switched into the second harmonicThe oscillator circuit 60 may be provided.
Illustratively, the first feed point F1And a second feed point F2Can be a metal spring pin (sheet) or a thimble, and the application does not limit the invention.
For example, the terminal device in the present application may be a mobile phone, a tablet computer, or a POS machine.
Optionally, the NFC control module 40 in this application is configured to provide a differential signal. The specific structure of the NFC control module 40 is not limited in this application.
It can be understood that, be provided with the NFC antenna in the metal frame in this application. Specifically, the NFC control module 40 is disposed in the NFC antenna, and the NFC control module 40 generates a differential signal to flow to the NFC antenna. For example, an NFC antenna system (including a chip and peripheral circuits referred to as an antenna system) (which may also receive signals, process the signals, and complete a final data transaction) may include: a near field communication chip (e.g., an NFC chip) and peripheral circuitry. For example, the peripheral circuit may be a filter circuit and an antenna matching circuit, the near field communication chip is connected to the filter circuit, the filter circuit is connected to the antenna matching circuit, and the antenna matching circuit is connected to the first feed point and the second feed point.
The application provides a near field communication antenna system, through set up the ground point in the metal frame to utilize and set up the first resonant circuit and the second resonant circuit in the metal frame and form a loop between ground point and the metal frame, the difference signal alright in order to form the backward flow along the loop of NFC control module output like this, thereby increased the circulation area of difference signal, increased the magnetic flux, thereby promote NFC's performance. In addition, the antenna system and other antennas provided by the application share the same structure, so that the degree of freedom is higher, and meanwhile, the influence on the realization and debugging of other antennas is reduced.
Illustratively, as shown in fig. 4, the metal bezel 30 in the present application is a frame body surrounded by a first bezel 301 and a second bezel 302 located above the first bezel 301 and having at least two spaces.
The specific structures of the first bezel 301 and the second bezel 302 are not limited in this application. As shown in fig. 4, for example, the first frame 301 may include two first vertical frames and two first horizontal frames arranged in parallel, wherein the two first vertical frames arranged in parallel are perpendicular to the first horizontal frame, and the two first vertical frames arranged in parallel are connected to the first horizontal frame. Of course, in the present application, each of the two first vertical frames disposed in parallel may include a first portion and a second portion, wherein the first portion and the second portion have a space therebetween, and the second portion is connected to the first horizontal frame.
As an example, the second bezel 302 includes: the second vertical frames are arranged in parallel and are perpendicular to the second horizontal frames, and the second vertical frames are connected with the second horizontal frames.
It should be noted that the antenna system for near field communication in the present application may further include other resonant circuits besides the first resonant circuit 50 and the second resonant circuit 60, and the specific structures of the other resonant circuits may be referred to the first resonant circuit 50 and the second resonant circuit 60, which is not reiterated herein. It should be understood that when the remaining resonant circuits are included in the near field communication antenna system, the NFC control module further has a third feed point therein for inputting a differential signal to the remaining resonant circuits. It should be noted that, if the NFC antenna and the other antennas share one metal entity, the third feed point may be located on the other antennas, but the third feed point may still be a signal fed by the NFC control module, and the signal fed by the NFC control module may be a signal other than the differential signal.
The first resonant circuit 50 and the second resonant circuit 60 in the present application have the same structure, and the following embodiments describe the specific structure of the first resonant circuit 50 and the second resonant circuit 60 in detail by taking the first resonant circuit as an example.
As shown in fig. 5, the first resonance circuit 50 in the present application includes: a first inductor 501, a first capacitor 502 and a second capacitor 503, wherein a first end of the first inductor 501 is connected to the second frame 302, and a second end of the first inductor 501 is connected to the second frame 503A first end of a capacitor 502 and a first end of a second capacitor 503 are connected, a second end of the first capacitor 502 is grounded, and a second end of the second capacitor 503 is connected to a first feed point F of the NFC control module1And (4) connecting. The second resonance circuit 60 includes: a first inductor 601, a first capacitor 602, and a second capacitor 603, wherein a first end of the first inductor 601 is connected to the second frame 302, a second end of the first inductor 601 is connected to a first end of the first capacitor 602 and a first end of the second capacitor 603, a second end of the first capacitor 602 is grounded, and a second end of the second capacitor 603 is connected to a second feed-in point F of the NFC control module2And (4) connecting.
It is understood that the first inductor 501, the first capacitor 502 and the second capacitor 503, the first inductor 601, the first capacitor 602 and the second capacitor 603 are all used to adjust the resonance point. The first ground point G1 and the second ground point G2 represent the lower points of the second bezel 302 to the PCB board disposed in the metal bezel, which is also the lower point of the NFC control module.
The ground point in the present application may be one ground point, or may be a group of ground points, and the group of ground points may include two or more ground points. Since the number and position of the grounding points vary due to the presence or absence of a gap between the first resonant circuit and the second resonant circuit, the following will be described in conjunction with specific embodiments:
it can be understood that, in the present application, when the first feeding point and the second feeding point are both used for outputting the differential signal output by the NFC control module 40, the first feeding point F is used for outputting the differential signal output by the NFC control module 401And a first feed point F in the present application1The phase of the fed-in differential signal and the second feeding point F2There is a phase difference between the fed differential signals. Illustratively, the phase difference between the two is 180 ° in the present application.
Fig. 6-8 described below will exemplify that the grounding point G may comprise a first grounding point G1 and a second grounding point G2, with the first grounding point G1 connected to the first resonant circuit 50 and the second grounding point G2 connected to the second resonant circuit 60, with no space between the first resonant circuit and the second resonant circuit. (note: only one G is used if there is no gap in the middle of the second rim 302 (or if there is no break in the middle), and G1 and G2 are needed if there is a gap). The absence of a gap between the first resonant circuit and the second resonant circuit is understood to mean that the second frame 302 to which the first resonant circuit and the second resonant circuit are connected does not have a gap or a gap separating the first resonant circuit and the second resonant circuit, and as shown in fig. 6 to 8, the top of the second frame 302 does not have a gap or a gap.
As shown in fig. 6, the first ground point G1 and the second ground point G2 may be located between the first resonant circuit 50 and the second resonant circuit 60, and the first ground point G1 and the second ground point G2 are connected to the second rim 302. In FIG. 6, a first feeding point F is used1The phase of the fed differential signal leads the second feed-in point F2The phase of the fed differential signal is 180 ° as an example:
as can be seen from fig. 6, the differential signal of the NFC control module 40 passes through the first feed point F1Fed into the first resonant circuit 50 through the first feed point F1The fed differential signal flows into the first ground point G1 through the second capacitor 503, the first inductor 501 and the metal frame 30 between the first inductor 501 and the first ground point G1. Since the first grounding point G1 and the second grounding point G2 are connected to the second frame 302, they pass through the first feeding point F1The fed differential signal flows from the first grounding point G1 to the second grounding point G2, and then flows to the second feeding point F through the metal frame 30 between the second grounding point G2 and the first inductor 601, the first inductor 601 and the second capacitor 6032And from the second feed-in point F2Is fed into the NFC control module 40. Thus, the first feeding point F is in one phase period1The fed differential signal is a loop in the whole phase period, so that the loop area can be increased, namely, the magnetic flux is increased, and the performance of the NFC is improved. At a second feed-in point F2From the second feed point F in the phase period2Differential signal fed in and first feed-in point F1The signal direction of the formed loop is opposite to the phase direction shown in fig. 6.
As shown in fig. 7, fig. 7 (the frame 302 is spaced apart in fig. 7, and when G1 and G2 are used, they should be spaced apart) shows a schematic diagram of the position relationship of another grounding point in the present application, and compared with fig. 6, in fig. 7, the first resonant circuit 50 and the second resonant circuit 60 are located between the first grounding point G1 and the second grounding point G2, and the first grounding point G1 and the second grounding point G2 are connected to the second frame 302. The paths of the differential signals in fig. 7 are the same as those in fig. 6, and the description of the present application is omitted here.
As shown in fig. 8, fig. 8 is different from fig. 6 in that the second grounding point G2 is located in the metal frame 30 in fig. 8, but the second grounding point G2 may not have a connection relationship with the second frame 302, and the second grounding point G2 is connected to the first inductor 601 (e.g., connected through a coil). The paths of the differential signals in fig. 8 are the same as those in fig. 6, and the description of the present application is omitted here.
It should be noted that when there is no space between the first resonant circuit 50 and the second resonant circuit 60, the first grounding point G1 may also be located between the first resonant circuit 50 and the second resonant circuit 60, and the second resonant circuit 60 may also be located between the first grounding point G1 and the second grounding point G2. Specifically, the paths of the differential signals can be referred to in fig. 6 to fig. 8, and the details of the present application are not repeated herein.
With reference to fig. 5, in fig. 5, it is assumed that there is no space between the first resonant circuit 50 and the second resonant circuit 60, and the grounding point G includes a grounding point. As shown in fig. 5, the first resonant circuit 50 and the second resonant circuit 60 are both connected to the ground point G, and the ground point G is connected to the second rim 302. I.e. the first 50 and second 60 resonant circuits share a ground point G. In order to form a large circulating current and increase the magnetic flux, the grounding point G may be disposed on the second frame 302, and the distances between the grounding point G and the first resonant circuit and the second resonant circuit are equal.
Fig. 9-11 described below will be exemplified with a second separation between the first resonant circuit and the second resonant circuit, the ground point G may comprise a first ground point G1 and a second ground point G2, and the first ground point G1 and the second ground point G2 are located on both sides of the second separation, wherein the first ground point G1 is connected to the first resonant circuit 50, and the second ground point G2 is connected to the second resonant circuit 60.
As shown in fig. 9, between the first resonance circuit 50 and the second resonance circuit 50There is a second spacing C, i.e. the second spacing separates the first resonant circuit 50 from the second resonant circuit 50. A first ground point G1 is located between the first resonant circuit 50 and the second resonant circuit 60 and a second resonant circuit 60 is located between a first ground point G1 and a second ground point G2. In order to make the first feed point F1A differential signal fed into the first resonant circuit 50 and a second feed point F2The current levels of the differential signals fed into the second resonant circuit 60 do not weaken each other, and in the present application, the differential signals may be fed into the second resonant circuit at the second feeding point F2And a second capacitor 603, a phase shift unit 70 is disposed between the first and second capacitors, the phase shift unit 70 is used for shifting the second feed point F2The phase of the differential signal fed to the differential signal in the second resonance circuit 60 is switched so that the second feed point F2Converting the phase of the differential signal fed into the second resonant circuit 60 to the first feed point F1The phases of the differential signals fed into the first resonant circuit 50 are the same.
Illustratively, the phase shift unit 70 may be a phase shifter. Such as balun.
Arrows (→) in fig. 9 show directions of differential signals output from the NFC control module 40. As can be seen from fig. 9, the differential signal output by the NFC control module 40 passes through the first feed point F1Is fed into the first resonant circuit 50 and flows to the first ground point G1 through the second capacitor 503, the first inductor 501 and the metal frame between the first ground point G1 and the first inductor 501 in the first resonant circuit 50 in sequence to form a first return current. Similarly, the differential signal output by the NFC control module 40 passes through the second feed point F2Is input into the second resonant circuit 60 and flows to the second ground point G2 through the second capacitor 603 in the second resonant circuit 60, the first inductor 601, and the metal frame between the second ground point G2 and the first inductor 601 in sequence to form a second return current. The purpose of shunting the differential signal output by the NFC control module 40 can be achieved by using the first ground point G1 and the second ground point G2, so as to achieve dual resonance, and because the first feed point F1And a second feed point F2The phase is the same. Therefore, the NFC communication bandwidth is increased by one of the two reflows, so that the magnetic flux of the NFC system is increased.
As shown in fig. 10, fig. 10 differs from fig. 9 in that a first grounding point G1 and a second grounding point G2 are located between the first resonant circuit 50 and the second resonant circuit 60 in fig. 10. As can be seen from fig. 10, the differential signal output by the NFC control module 40 passes through the first feed point F1Is fed into the first resonant circuit 50 and flows to the first ground point G1 through the second capacitor 503, the first inductor 501 and the metal frame between the first ground point G1 and the first inductor 501 in the first resonant circuit 50. Since the first ground point G1 and the second ground point G2 are located on the PCB or FPC, the first feed point F is fed from the first feed point F1The differential signal fed into the first resonant circuit 50 flows to the second grounding point G2 through the first grounding point G1, and then passes through the second feeding point F after passing through the metal frame between the second grounding point G2 and the first inductor 601, the second capacitor 6032Flows into the NFC control module 40 to form a loop, thereby increasing the current area of the differential signal output from the NFC control module so that the magnetic flux increases.
As shown in fig. 11, fig. 11 differs from fig. 9 in that the first resonant circuit 50 and the second resonant circuit 60 are located between the first grounding point G1 and the second grounding point G2 in fig. 11. In fig. 11, the differential signal output by the NFC control module 40 passes through the first feed point F1Is fed into the first resonant circuit 50 and flows to the first ground point G1 through the second capacitor 503, the first inductor 501 and the metal frame between the first ground point G1 and the first inductor 501 in the first resonant circuit 50. A first feed point F1The fed differential signal flows to the second grounding point G2 through the first grounding point G1 and the PCB, and is input to the second feeding point F through the metal frame between the second grounding point G2 and the first inductor 601, the first inductor 601 and the third capacitor 6032To form a loop.
Optionally, the access point in this application is connected to the second frame through a metal block elastic connecting piece or a lock screw, and the first end of the first inductor 501 and the first end of the first inductor 601 are connected to the second frame through metal block elastic connecting pieces or lock screws.
Note that, in the present embodiment, a PCB (e.g., a Flexible Printed Circuit Board (FPC)) is disposed in the accommodating space, and the PCB may be used to arrange components, for example, various components included in the first resonant Circuit 50 and the second resonant Circuit 60 in the present embodiment, a first grounding point, a second grounding point, and the like.
In fig. 9, the second frame 302 to which the first ground point G1 and the second ground point G2 are connected has a gap C, it can be understood that the gap C on the second frame 302 not only improves the flexibility of the NFC antenna design, but also the performance of the NFC antenna is higher than that of the NFC antenna without the gap C on the second frame 302. But the performance of the NFC antenna without the gap C on the second frame 302 is high compared to the NFC antenna without the ground point G.
Referring to fig. 9, the first feeding point F is adjusted first in the embodiment of the present invention1The resonant point of the first resonant circuit is slightly higher than the carrier frequency 13.56MHz specified by the actual required protocol by the upper matching circuit (i.e. the matching circuit corresponding to F1 in the NFC antenna), and then the second feed point F is adjusted2The corresponding matching circuit (i.e., the matching circuit corresponding to F2 in the NFC antenna) is to slightly lower the second resonant circuit 60 than 13.56MHz, so that the first resonant circuit 50 and the second resonant circuit 60 are close to each other, thereby increasing the bandwidth, and the specific debugging result is shown in fig. 12. In fig. 12, a line marked with 1 is a debugging result of the NFC antenna structure shown in fig. 1, a line marked with 2 is a debugging result of the NFC antenna structure shown in fig. 2, and a line marked with 3 is a debugging result of the near field antenna system provided in the embodiment of the present application.
As can be seen from fig. 10, the first resonant circuit 50 and the second resonant circuit 60 are merged together in the embodiment of the present application, so that the effect of increasing the bandwidth is obvious, and the bandwidth calculated in the above embodiment can be completely covered. Since the first resonance circuit 50 and the second resonance circuit 60 are provided, two subcarrier modulation signals can be contained. As can be seen from fig. 13, fig. 13 is a schematic diagram illustrating comparison between the card swiping result of the NFC near-field antenna system provided in the embodiment of the present application applied to the terminal device and the card swiping result of the first prior art and the card swiping result of the second prior art. In fig. 13, a line marked with 4 is a card swiping result of the NFC near-field antenna system provided in the embodiment of the present application applied to the terminal device. The line marked 5 is a card swiping result of the NFC antenna structure provided by the second prior art applied to the terminal device. The line marked 6 is a card swiping result of the NFC antenna structure applied to the terminal device provided in the first prior art. Comparing the three lines in fig. 13, it can be determined that the card swiping area of the NFC near-field antenna system provided in the embodiment of the present application applied to the terminal device is improved significantly, so that the scheme has certain feasibility for increasing the card swiping area. Table 1 shows area comparison of the coils of the near field communication antenna systems provided in the first prior art, the second prior art and the present application:
TABLE 1 area of the coils of the different antenna systems
An embodiment of the present application further provides a terminal device, where the terminal device has the above metal frame, the metal frame is used as the outer peripheral portion of the terminal device, the metal frame has at least two intervals located on different sides, and the terminal device further includes: the near field communication antenna system provided by the embodiment of the invention; in the terminal device, a near field communication antenna system is used in the terminal device for transmitting and receiving signals.
Optionally, the battery rear cover of the terminal device may be a non-metal rear cover, or may be a frame of a metal rear cover, which is not limited in this application. It can be practiced as long as the battery back cover portion and the metal frame portion are separated by a gap and are not integrally connected.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (5)
1. The near field communication antenna system is applied to terminal equipment, wherein the terminal equipment comprises a metal frame, and the antenna system comprises: the NFC control module is arranged in the metal frame, the first resonant circuit and the second resonant circuit are connected with the NFC control module, and the grounding point is arranged in the metal frame; the metal frame is provided with at least two intervals positioned on different sides; the ground point comprises a first ground point and a second ground point;
the NFC control module is used for generating a differential signal;
the first resonant circuit is connected with the metal frame, is also connected with the first grounding point through the metal frame, and is used for outputting the differential signal output by the NFC control module to a Printed Circuit Board (PCB) through the first grounding point;
the second resonant circuit is connected with the metal frame, is also connected with the second grounding point through the metal frame, and is used for feeding a differential signal which is input to the second resonant circuit through the PCB and the second grounding point into the NFC control module;
the metal frame is enclosed by first frame and the second frame that is located first frame top and is become to have two at least spaced frameworks, first resonant circuit and second resonant circuit are the same, first resonant circuit includes: the NFC control module comprises a first inductor, a first capacitor and a second capacitor, wherein the first end of the first inductor is connected with the second frame, the second end of the first inductor is connected with the first end of the first capacitor and the first end of the second capacitor, the second end of the first capacitor is grounded, and the second end of the second capacitor is connected with the NFC control module.
2. The antenna system of claim 1, wherein the first ground point is connected to the first resonant circuit, the second ground point is connected to the second resonant circuit, the first ground point is located between the first resonant circuit and the second resonant circuit, and the second resonant circuit is located between the first ground point and the second ground point, the first ground point and the second ground point are connected to the metal bezel.
3. The antenna system of claim 1, wherein the first ground point is connected to the first resonant circuit, wherein the second ground point is connected to the second resonant circuit, and wherein the first ground point and the second ground point are located between the first resonant circuit and the second resonant circuit when the first ground point and the second ground point are connected to the metal bezel or the first ground point is connected to the metal bezel.
4. The antenna system of claim 1, wherein the first resonant circuit and the second resonant circuit are located between the first ground point and the second ground point, the first ground point and the second ground point being connected to the metal bezel.
5. The utility model provides a terminal equipment, its characterized in that, terminal equipment includes the metal frame, including two at least intervals that are located different sides on the metal frame, terminal equipment still includes: the near field communication antenna system of any one of claims 1 to 4;
the near field communication antenna system is used in the terminal equipment for transmitting and receiving signals.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CN2018/084283 WO2019204988A1 (en) | 2018-04-24 | 2018-04-24 | Near field communication antenna system and terminal device |
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| Publication Number | Publication Date |
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| CN111279549A CN111279549A (en) | 2020-06-12 |
| CN111279549B true CN111279549B (en) | 2022-01-14 |
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| CN201880069763.8A Active CN111279549B (en) | 2018-04-24 | 2018-04-24 | Near field communication antenna system and terminal equipment |
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| WO (1) | WO2019204988A1 (en) |
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| WO2022017017A1 (en) * | 2020-07-21 | 2022-01-27 | Oppo广东移动通信有限公司 | Antenna apparatus and electronic device |
| CN212783782U (en) * | 2020-09-01 | 2021-03-23 | Oppo广东移动通信有限公司 | Electronic device |
| CN112422724A (en) * | 2020-11-20 | 2021-02-26 | 维沃移动通信有限公司 | Circuit structure, control method, device, electronic equipment and readable storage medium |
| CN112467339B (en) * | 2020-11-23 | 2023-12-01 | 维沃移动通信有限公司 | Antenna and electronic equipment |
| CN112952358B (en) * | 2021-01-28 | 2023-07-28 | Oppo广东移动通信有限公司 | Antenna device and electronic equipment |
| CN113437520B (en) * | 2021-06-29 | 2022-08-16 | RealMe重庆移动通信有限公司 | Antenna device and electronic apparatus |
| CN115313037A (en) * | 2022-08-31 | 2022-11-08 | Oppo广东移动通信有限公司 | Antenna assembly and electronic equipment |
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| CN111279549A (en) | 2020-06-12 |
| WO2019204988A1 (en) | 2019-10-31 |
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