CN104362425A - Mobile terminal realizing NFC antenna sharing - Google Patents

Abstract

The invention provides a mobile terminal sharing an NFC antenna, comprising: an NFC module, a high-frequency module, a link module and an antenna module, the link module is used to separate the operating frequency of the NFC module and the operating frequency of the high-frequency module, and the antenna module is used for Generate the resonant frequency required for the operation of the NFC module and the resonant frequency required for the operation of the high-frequency module. In the present invention, by adding a link module, the NFC module and the corresponding antenna are connected through the link module, so that the NFC signal can be transmitted through the original antenna, and antenna sharing is realized, and no additional independent NFC antenna is required, which effectively reduces the difficulty of design. The equipment space is saved, the equipment cost is also reduced, and the invention has a good application prospect.

Description

A mobile terminal sharing an NFC antenna

technical field

The invention relates to the field of mobile device antenna design, in particular to a mobile terminal sharing an NFC antenna.

Background technique

With the development of communication technology, mobile communication products such as mobile phones have become indispensable equipment for people. The NFC function has gradually become an essential function of mobile communication devices.

Near Field Communication (NFC) is a short-range high-frequency radio technology with a working frequency of 13.56MHz and operates within a distance of 20 cm. NFC has the characteristics of short-distance communication, and has the advantages of low power consumption, direct communication between mobile or other electronic devices, and high confidentiality and security. It has gradually become an essential function of various mobile devices. .

With the rapid development of mobile phone communication technology, LTE (Long Term Evolution, commonly known as 4G), WIFI/BT, GPS, wireless charging, and NFC have become indispensable functions of mobile communication devices, but the devices still need more antennas Provided for use by different functional modules. As shown in FIG. 1 , the existing mobile phone design framework generally includes a baseband chip 50 , an NFC module 300 , a radio frequency module 500 , a GPS/WIFI module 70 and an antenna module. The antenna module specifically includes a main antenna 10 , a diversity antenna 20 , a GPS/WIFI antenna 30 and an NFC antenna 80 . With the increase of functions, mobile communication devices such as mobile phones need to add more and more antennas. However, the design of each antenna on a mobile device such as a mobile phone requires a certain amount of space and cost. The more antennas there are, the more space the device needs, and the cost increases, making the design more and more difficult. In particular, the NFC antenna occupies a relatively large space. In order to avoid interference, it is necessary to add an expensive ferrite with an area equivalent to that of the NFC antenna.

Contents of the invention

In view of the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a mobile terminal that shares an NFC antenna, aiming at solving the problems that an additional NFC antenna needs to be installed in the existing mobile device, high cost, large space occupation, and difficult design .

In order to achieve the above object, the present invention has taken the following technical solutions:

A mobile terminal sharing an NFC antenna, comprising: an NFC module, at least one high-frequency module, at least one link module for separating the operating frequency of the NFC module and the operating frequency of the high-frequency module, and at least one link module for generating the operating frequency of the NFC module. The resonant frequency and the antenna module of the resonant frequency required for the high frequency module to work, the NFC module and the high frequency module are all connected to the antenna module through the link module.

In the mobile terminal sharing the NFC antenna, the link module includes a first inductor and a first capacitor, one end of the first capacitor and one end of the first inductor are connected to the antenna module, and the other end of the first capacitor is connected to the high frequency module, and the other end of the first inductor is connected to the NFC module.

In the mobile terminal sharing the NFC antenna, the inductance of the first inductor is 50-120nh, and the capacitance of the first capacitor is 50-120pf.

In the mobile terminal sharing the NFC antenna, the antenna module includes a second capacitor, one or two antenna branches, and each antenna branch includes a second inductance; the second inductance is located at the end or middle of the corresponding antenna branch , one end of the second inductor is grounded, the other end of the second inductor is grounded through a second capacitor, and is also connected to the link module.

In the mobile terminal sharing the NFC antenna, the inductance of the second inductor is 30-120nh, and the capacitance of the second capacitor is greater than 12pf.

In the mobile terminal sharing the NFC antenna, there is at least one high-frequency module, and when the number of the high-frequency modules is more than two, the number of antenna modules and the number of link modules are greater than or equal to the number of high-frequency modules Quantity; the mobile terminal also includes a splitter, which is used to select one of the multiple antenna modules to connect to the NFC module when the NFC module is working; the NFC module is connected to each link module through the splitter.

In the mobile terminal sharing the NFC antenna, the high-frequency module is a radio frequency module and a GPS/WIFI module.

In the mobile terminal sharing the NFC antenna, the mobile terminal further includes a main antenna, and the radio frequency module is also connected to the main antenna through a link module.

Beneficial effects: the mobile terminal sharing the NFC antenna provided by the present invention, by adding a link module, the NFC module and the corresponding antenna are connected through the link module, so that the NFC signal can be transmitted through the original antenna, antenna sharing is realized, and no additional independent settings are required. The advanced NFC antenna effectively reduces the difficulty of design, saves equipment space, and also reduces equipment costs, and has a good application prospect. the

Description of drawings

FIG. 1 is a frame diagram of mobile phone antenna design in the prior art.

Fig. 2 is a structural block diagram of a preferred embodiment of a mobile terminal sharing an NFC antenna provided by the present invention.

FIG. 3 is a circuit diagram of a specific embodiment of an antenna of a mobile terminal sharing an NFC antenna provided by the present invention.

Fig. 4 is a structural block diagram of another preferred embodiment of a mobile terminal sharing an NFC antenna provided by the present invention.

FIG. 5 is a structural block diagram of a specific embodiment of a mobile terminal sharing an NFC antenna provided by the present invention, taking a radio frequency module as an example.

Detailed ways

The invention provides a mobile terminal sharing an NFC antenna. In order to make the object, technical solution and effect of the present invention more clear and definite, the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in FIG. 2 , a preferred embodiment of a mobile terminal sharing an NFC antenna provided by the present invention includes an NFC module 300 , at least one high-frequency module 400 , at least one antenna module 100 and at least one link module 200 . The NFC module 300 and the high frequency module 400 are respectively connected to the antenna module 100 through the link module 200 .

The antenna module 100 can generate both low-frequency resonance frequency (specifically determined by the operating frequency of the NFC module), and high-frequency resonance frequency (corresponding to the operating frequency of the high-frequency module), so that the antenna module 100 can meet the low-frequency requirements at the same time. NFC signal and the requirements of the working signal required for the high-frequency module to work. The link module 200 can separate the operating frequency of the NFC module and the operating frequency of the high-frequency module (for example, the operating frequency of the NFC is 13.56MHz, and the operating frequency of the radio frequency is above 700Mhz), which plays a duplex role, so that the NFC module 300 and the high-frequency module The frequency modules 400 can work simultaneously.

The present invention adopts the antenna module 100 and the link module 200 that can generate high-frequency and low-frequency resonance frequencies, so that the high-frequency module 400 and the NFC module 300 will not affect each other while sharing the same antenna, and can work at the same time, reducing the number of antennas , thereby effectively solving the problems of high cost and difficult design of separately setting the NFC antenna.

It should be noted that the high-frequency module 400 can be a module with a large difference between any work in the mobile device and the NFC work frequency point, and it can be a module of more than one to two orders of magnitude, such as a radio frequency module, GPS/WIFI modules etc. For the convenience of explanation, the radio frequency module 500 is taken as an example for description below.

Specifically, in order to separate NFC and radio frequency operating frequencies, as shown in FIG. 5 , the link module 200 includes a first inductor L1 and a first capacitor C1. One end of the first capacitor C1 and one end of the first inductor L1 are both connected to the antenna module 100 , the other end of the first capacitor C1 is connected to the radio frequency module 500 , and the other end of the first inductor L1 is connected to the NFC module 300 . The link module 200 can achieve a good technical effect of separating high-frequency and low-frequency signals by utilizing the characteristics of capacitive elements passing high frequencies and blocking low frequencies and inductive elements passing low frequencies and blocking high frequencies.

The function of the first capacitor C1 is mainly to block the signal of the NFC working frequency, so as to avoid affecting the normal operation of the radio frequency module. Similarly, the role of the inductance is to block radio frequency signals and avoid interfering with the normal operation of the NFC module, so that the NFC module 300 and the radio frequency module 500 can work simultaneously without affecting each other. In general, in order to provide sufficient impedance and realize the separation of high and low frequencies, the inductance of the first inductor can be set to 50~120nh, and the capacitance of the first capacitor can be set to 50~120pf. Of course, according to the needs of the actual situation, if there are special requirements for impedance and sensitivity, the capacitance value can be appropriately expanded to 150pf or reduced to 22~33pf. Correspondingly, the inductance value of the inductor can be properly enlarged to 150nh or reduced to 30nh.

More specifically, since NFC is a near-field communication that mainly relies on magnetic field coupling for information transmission, the antenna in the antenna module adopts the design of a loop antenna, while the existing antennas (such as the main antenna, diversity antenna and GPS/WIFI antenna) all use Inverted F antenna design. Therefore, in order to realize that the antenna module 100 needs to meet the requirements of applying NFC signals and radio frequency signals at the same time, improvements can be made on the grounding points of the antenna branches.

As shown in FIG. 3 , the antenna module 100 includes a second capacitor C2 and one or two antenna branches. Taking the antenna module including two antenna branches as an example, the two antenna branches include the first low-frequency resonant frequency of 700M~1GHz. An antenna branch 110 and a second antenna branch 120 generating a high-frequency resonance frequency of 1700-2700 MHz, the two antenna branches have one to two common ground points.

Taking a public ground point A in Figure 3 as an example, a second capacitor C2 is added to the ground point A. Due to the electrical characteristics of the second capacitor C2, it can provide extremely low impedance for frequencies above 700MHz (that is, radio frequency signals), and at the same time Form a very large impedance to the NFC frequency point (for example, 13.5MHz), form a barrier to it, make the RF signal go from this path to the ground, and prevent the NFC signal from this path to the ground. In general, the capacitance of the second capacitor should be greater than 12pf. In special cases, it can be appropriately expanded to 150pf.

In the antenna module 100, each antenna branch includes a second inductor L2; the second inductor L2 is located at the end or middle of the corresponding antenna branch, one end of the second inductor L2 is grounded, and the other end of the second inductor L2 One end is connected to the ground through the second capacitor C2 and also connected to the link module 200 .

If only one antenna branch is provided for the NFC signal, a second inductor L2 may be provided at the end or middle of the antenna branch. The function of the second inductance L2 is opposite to that of the second capacitor C2, which can provide low impedance for the NFC frequency point, allowing the NFC frequency signal to go from this path to the ground, and form a high impedance for the frequency above 700MHz to play a blocking role, avoiding the frequency above 700MHz The frequency point is from this path to the ground.

In general, setting the inductance value of the second inductor to 30-120nh can meet the impedance requirement. It should be noted that the above-mentioned second inductance set at the ground point of the antenna can also adjust the inductance value according to the actual situation, and play a role in matching NFC, so that the antenna can generate the resonant frequency required by the NFC module.

In actual use, L2 in Figure 3 is connected to the end of the corresponding antenna branch, and L2` is connected to the middle of the corresponding antenna branch. When actually designing the antenna module, you can choose to use the L2 branch of the first antenna branch 110 (as shown in Figure 3 The branch where the grounding point B is located) or the L2` branch (as shown in Figure 3, the branch where the grounding point B` is located), or the L2 branch of the second antenna branch 120 (as shown in Figure 3, the branch where the grounding point C is located) can also be selected road) or L2` branch (as shown in Figure 3 where the ground point C` is located). Therefore, there are four design schemes for the antenna of one antenna branch (that is, a branch where B or B` or C or C` is located can be selected), which can be selected according to specific situations.

If it is necessary to provide two antenna branches for the NFC signal, the second inductor can be connected to the end or middle of the first antenna branch 110, and the second inductor can be connected to the end or middle of the second antenna branch 120. When designing the antenna, The branches where the ground point B and the ground point C are located can be selected as the first antenna branch and the second antenna branch of the antenna module respectively, and the branches where the ground point B and the ground point C` are located can also be selected as the first antenna branch of the antenna module and the second antenna branch, you can also choose the branch where the ground point B` and the ground point C are located as the first antenna branch and the second antenna branch of the antenna module, and you can also choose the branch where the ground point B` and the ground point C` are located serve as the first antenna branch and the second antenna branch of the antenna module respectively.

The grounding points B and C of the present invention are taken as an example. As shown in FIG. 3 , the two arrows represent the loop of the NFC signal. The NFC signal passes through the two antenna branches of the antenna from the link module 200 , and then passes through B and C to the ground.

In the above embodiment, the NFC module shares an antenna with an existing module (such as a radio frequency module) of the mobile terminal. Once the product is fixed, the antenna shared with the NFC module cannot be changed. The second preferred embodiment provided by the present invention can be selected in real time according to the actual situation. In the embodiment shown in FIG. 4, there is at least one high-frequency module. When the number of the high-frequency modules is more than two, The number of antenna modules and the number of link modules are greater than or equal to the number of high frequency modules. And the mobile terminal also needs to include a splitter 40 for selecting one of the multiple antenna modules to connect with the NFC module 300 when the NFC module is working; the NFC module 300 is connected to each link module 200 through the splitter 40 .

When there are two high-frequency modules, the high-frequency module radio frequency module 500 and the GPS/WIFI module 70 are used, and the antenna modules are the diversity antenna 20 and the GPS/WIFI antenna 30 . The diversity antenna 20 is connected to the splitter 200 through a link module 200 , and the GPS/WIFI antenna 30 is also connected to the splitter 200 through a link module 200 .

Taking the mobile terminal as a mobile phone as an example, in order to ensure the normal operation of the mobile phone, the mobile phone also needs to include a main antenna 10 and a baseband chip 50. At this time, a link module 200 needs to be added to the mobile phone, and the radio frequency module 500 is also connected to the main antenna 10 through a link module. , the baseband chip is respectively connected to the radio frequency module 500, the GPS/WIFI module 70 and the NFC module 300, and controls the work of the radio frequency module 500, the GPS/WIFI module 70 and the NFC module 300.

In this embodiment, the number of link modules corresponds to the number of antennas, and the splitter 40 functions as a switch to control the connection relationship between the NFC module and multiple shared antennas. The current commercial operating frequency of NFC on the market is 13.56MHz. If there is a new operating frequency, such as 20M or 30M, which is suitable for near-field communication, it can be debugged through the splitter 40 and share one of the above-mentioned antennas to allow NFC Work at multiple different frequency points.

It should be noted that the splitter 40 can be designed as a duplexer or a triplexer according to the number of operating frequency points actually required.

If the NFC module only works at a single frequency point, the splitter 40 can also use its switching function to read the field strengths of different antennas in a very short time, and select the antenna with the best field strength among multiple antennas to work.

In general, the splitter plays two roles. The first one is to allow NFC to work at different frequency points at the same time (not limited to 13.56MHz, but can work at different frequency points at the same time, such as 20/30MHz), The shared design of the NFC antenna and different antennas makes the NFC application range wider. The second one belongs to the role of smart antennas. Multiple shared antennas of NFC work at the same frequency point. When NFC is turned on, it switches between multiple antennas in real time, reads the strength of the received field, and selects the antenna with the best effect to work. .

In summary, the present invention provides a mobile terminal that shares an NFC antenna. By adding a link module, the NFC module and the corresponding antenna are connected through the link module, so that the NFC signal can be transmitted through the original antenna without additionally setting up an independent terminal. The NFC antenna effectively reduces the difficulty and cost of design, and saves equipment space. In addition, by setting the splitter, the frequency range of NFC application is wider. It can also switch multiple antennas in real time, read the received field strength, and intelligently select the one with the best performance for communication, which has a good application prospect.

It can be understood that those skilled in the art can make equivalent replacements or changes according to the technical solutions of the present invention and the concept of the present invention, and all these changes or replacements should belong to the protection scope of the appended claims of the present invention.

Claims (8)

1. A mobile terminal sharing an NFC antenna, comprising: an NFC module and at least one high-frequency module, characterized in that it also includes at least one link module for separating the operating frequency of the NFC module and the operating frequency of the high-frequency module; For the antenna module that generates the resonant frequency required for the operation of the NFC module and the resonant frequency required for the operation of the high-frequency module, both the NFC module and the high-frequency module are connected to the antenna module through the link module. 2. The mobile terminal sharing the NFC antenna according to claim 1, wherein the link module includes a first inductor and a first capacitor, and one end of the first capacitor and one end of the first inductor are connected to the antenna module , the other end of the first capacitor is connected to the high frequency module, and the other end of the first inductor is connected to the NFC module. 3. The mobile terminal sharing an NFC antenna according to claim 2, wherein the inductance of the first inductor is 50-120nh, and the capacitance of the first capacitor is 50-120pf. 4. The mobile terminal sharing the NFC antenna according to claim 1, wherein the antenna module comprises a second capacitor, one or two antenna branches, and each antenna branch comprises a second inductance; the second The inductor is located at the end or middle of the corresponding antenna branch, one end of the second inductor is grounded, the other end of the second inductor is grounded through the second capacitor, and is also connected to the link module. 5. The mobile terminal sharing an NFC antenna according to claim 4, wherein the inductance of the second inductor is 30-120nh, and the capacitance of the second capacitor is greater than 12pf. 6. According to the mobile terminal of the shared NFC antenna described in any one of claims 1 to 5, it is characterized in that there is at least one said high-frequency module, and when the quantity of said high-frequency module is more than two, the number of antenna modules The quantity and the quantity of the link module are greater than or equal to the quantity of the high-frequency module; The mobile terminal also includes a splitter, which is used to select one of the multiple antenna modules to be connected to the NFC module when the NFC module is working; the NFC module passes through the splitter Connect each link module. 7. The mobile terminal sharing an NFC antenna according to claim 6, wherein the high frequency module is a radio frequency module or a GPS/WIFI module. 8. The mobile terminal sharing an NFC antenna according to claim 7, wherein the mobile terminal further comprises a main antenna, and the radio frequency module is also connected to the main antenna through a link module.