NFC antenna and NFC communication device

Abstract

The utility model discloses an NFC antenna and NFC communication equipment, and the NFC antenna comprises a substrate which comprises a first surface and a second surface which are oppositely disposed, the first surface is provided with an active end and a terminal, and the substrate is provided with a first through hole, a second through hole to an Nth through hole in a penetrating manner; the coil comprises a wiring body, a wiring starting end and a wiring tail end are arranged at the two ends of the wiring body respectively, the wiring starting end is connected to the source end, the wiring body sequentially penetrates through the first through hole, the second through hole to the Nth through hole, and the wiring tail end is connected to the terminal. According to the NFC antenna, the inductance value is compensated through the via hole, and the wiring length of the wiring body on the first surface and the second surface is shortened, so that the number of turns of the coil on the first surface and the second surface is reduced, and the overall size of the substrate can be reduced; in addition, the number of substrate layers can be reduced, and cost is reduced.

Description

Technical Field

[0001] This application relates to the field of antenna communication technology, and in particular to an NFC antenna and an NFC communication device. Background Technology

[0002] Near Field Communication (NFC) is a technology that uses magnetic field induction to transmit and receive electromagnetic waves to enable communication between electronic devices at close range. Devices using NFC (such as mobile phones) can exchange data when they are close to each other, enabling applications such as mobile payments, electronic ticketing, access control, and anti-counterfeiting.

[0003] Some existing NFC antennas are made of multi-layer PCBs, which not only increases the cost but also makes them too large. Utility Model Content

[0004] This application provides an NFC antenna and an NFC communication device to solve the technical problem that some existing NFC antennas are multi-layer PCBs, which not only increases the cost but also makes them too large.

[0005] To address the aforementioned technical problems, this application proposes an NFC antenna, comprising: a substrate, including a first surface and a second surface disposed opposite to each other, the first surface being provided with a source end and a terminal end, the substrate being provided with a first via, a second via, and up to an Nth via; and a coil, including a trace body, the trace body having a trace start end and a trace end end respectively at both ends, the trace start end being connected to the source end, the trace body being sequentially provided with the first via, the second via, and up to the Nth via, and the trace end being connected to the terminal end, so that the trace body is arranged in a ring shape.

[0006] The trace body includes several first sub-traces, several transition traces, and several second sub-traces. The several first sub-traces are located on a first surface, the several transition traces are located in different vias, and the several second sub-traces are located on a second surface. A first sub-traces, a transition trace, and a second sub-traces are connected sequentially. The connection position between the end of a first sub-traces away from the source and the end of a transition trace is located above the first via. The connection position between the other end of a transition trace and the end of a second sub-traces is located below the first via. This continues until the connection position between N first sub-traces and N transition traces is located above the Nth via. The N first sub-traces are connected to the terminal.

[0007] The coil comprises several wire loops arranged in a ring shape; the number of the Nth via is n, where n = L. NFC / (2*l1*[ln(l1 / D1)-K]*N 1.8 +5.08h[ln(4h / d)+1]); where L NFC1 is the inductance value required for the NFC antenna; l1 is the length of one loop of wire in cm; D1 is the width of the loop; N is the number of loops; h is the length of the via; d is the diameter of the via.

[0008] The spacing between adjacent vias is s = c / n, where c is the total length of the coil and n is the number of the Nth via.

[0009] The spacing between adjacent vias is greater than or equal to 0.2 mm.

[0010] The diameter of the via is greater than or equal to 0.2 mm and less than or equal to 0.3 mm.

[0011] The number of conductor loops is greater than or equal to 2 and less than or equal to 5.

[0012] The width of the conductor loop is greater than or equal to 0.25 mm and less than or equal to 1 mm.

[0013] The thickness of the substrate along the first direction is greater than or equal to 1.2 mm and less than or equal to 2.0 mm; the first direction is the direction from the first surface to the second surface.

[0014] To address the aforementioned technical problems, this application proposes an NFC communication device, including the NFC antenna described above.

[0015] The beneficial effects of this application are as follows: Unlike existing technologies, this application provides an NFC antenna including a substrate and a coil. The substrate includes a first surface and a second surface disposed opposite to each other. The first surface has a source end and a terminal end. The substrate has a first via, a second via, and so on up to an Nth via. The coil includes a trace body. The trace body has a trace start end and a trace end end at both ends. The trace start end is connected to the source end. The trace body sequentially passes through the first via, the second via, and so on up to the Nth via. The trace end end is connected to the terminal end.

[0016] At least a portion of the trace body is distributed on the first and second surfaces of the substrate; simultaneously, the number of vias is increased on the substrate, and at least a portion of the trace body is also distributed in the vias. By using the vias to compensate for the inductance value, the trace body's routing length on the first and second surfaces is shortened, thereby reducing the number of turns of the coil on the first and second surfaces, and thus reducing the overall size of the substrate; furthermore, it can reduce the number of substrate layers and lower costs, etc. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0018] Figure 1 This is a first structural schematic diagram of an embodiment of the NFC antenna of this application;

[0019] Figure 2 This is a first partial schematic diagram of an embodiment of the NFC antenna of this application;

[0020] Figure 3 This is a second structural schematic diagram of an embodiment of the NFC antenna of this application;

[0021] Figure 4 This is a second partial schematic diagram of an embodiment of the NFC antenna of this application;

[0022] Figure 5 This is a partial cross-sectional schematic diagram of an embodiment of the NFC antenna of this application.

[0023] Reference numerals in the figures: 10, NFC antenna; 11, substrate; 11a, first surface; 111a, source end; 111b, terminal; 11b, second surface; 111, first via; 112, second via; 11N, Nth via; 12, coil; 121, trace body; 121a, trace start end; 121b, trace end; 1211, first sub-trace; 1212, transition trace; 1213, second sub-trace; 122, conductor loop. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] The NFC antenna and NFC communication device provided by this utility model will be described in detail below with reference to the embodiments.

[0027] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 , Figure 1 This is a first structural schematic diagram of an embodiment of the NFC antenna of this application; Figure 2 This is a first partial schematic diagram of an embodiment of the NFC antenna of this application; Figure 3 This is a second structural schematic diagram of an embodiment of the NFC antenna of this application; Figure 4 This is a second partial schematic diagram of an embodiment of the NFC antenna of this application. This application provides an NFC antenna. The NFC antenna 10 includes a substrate 11 and a coil 12. The substrate 11 includes a first surface 11a and a second surface 11b disposed opposite to each other. The first surface 11a is provided with a source end 111a and a terminal end 111b. The substrate 11 is permeated by a first via 111, a second via 112, and up to an Nth via 11N. The substrate 11 may be permeated by, but is not limited to, the first via 111, the second via 112, a third via (not shown in the figure), a fourth via (not shown in the figure), a fifth via (not shown in the figure), a sixth via (not shown in the figure), and so on up to the Nth via 11N. The coil 12 includes a trace body 121. The trace body 121 has a trace start end 121a and a trace end end 121b at both ends. The trace start-up 121a is located at the beginning of the trace body 121; the trace end-up 121b is located at the end of the trace body 121.

[0028] The trace start end 121a is connected to the source end 111a, realizing the connection between the trace 121 and the source end 111a. The trace body 121 sequentially passes through the first via 111, the second via 112, and up to the Nth via 11N. Specifically, the trace body 121 passes from the first via 111 on the first surface 11a to the first via 111 on the second surface 11b, the second via 112 on the second surface 11b to the second via 112 on the first surface 11a, the third via on the first surface 11a to the third via on the second surface 11b, the fourth via on the second surface 11b to the fourth via on the first surface 11a, the fifth via on the first surface 11a to the fifth via on the second surface 11b, and so on, until the trace body 121 passes through the Nth via 11N on the first surface 11a. The trace end 121b of the trace body 121 is connected to the terminal 111b.

[0029] At least a portion of the trace body 121 is distributed on the first surface 11a and the second surface 11b of the substrate 11; simultaneously, the number of vias is increased on the substrate 11, and at least a portion of the trace body 121 is also distributed in the vias. In this way, the inductance value is compensated by the vias, the trace length of the trace body 121 on the first surface 11a and the second surface 11b is shortened, thereby reducing the number of turns of the coil 12 on the first surface 11a and the second surface 11b, and thus reducing the overall size of the substrate 11; in addition, the number of layers of the substrate 11 can be reduced, and the cost can be reduced, etc.

[0030] The vias described above are conductive channels used to connect copper foil traces of different layers. Vias act as conductive bridges. They are formed by drilling holes in the circuit board and then plating copper onto the hole walls.

[0031] Please see Figure 5 , Figure 5 This is a partial cross-sectional schematic diagram of an embodiment of the NFC antenna of this application. Combined with... Figures 1 to 4 In some embodiments, the trace 121 includes a plurality of first sub-traces 1211, a plurality of transition traces 1212, and a plurality of second sub-traces 1213. The number of first sub-traces 1211, transition traces 1212, and second sub-traces 1213 is not limited, as long as the trace body 121, after passing through the aforementioned Nth via 11N, can meet the inductance value requirements of the NFC antenna 10.

[0032] A plurality of first sub-routes 1211 are located on a first surface 11a. All first sub-routes 1211 are located on the first surface 11a. A plurality of transition routes 1212 are located in different vias. All transition routes 1212 are located within different vias, and each via can contain one transition route 1212. A plurality of second sub-routes 1213 are located on a second surface 11b. All second sub-routes 1213 are located on the second surface 11b.

[0033] When the routing body 121 includes the first sub-routes 1211, the transition routes 1212 and the second sub-routes 1213, the routing body 121 sequentially passes through the first vias 111, the second vias 112 and up to the Nth via 11N. The arrangement of the plurality of first sub-routes 1211, the plurality of transition routes 1212 and the plurality of second sub-routes 1213 is as follows.

[0034] For example, a first sub-trace 1211, a transition trace 1212, and a second sub-trace 1213 are connected sequentially. The transition trace 1212 is disposed adjacent to both the first sub-trace 1211 and the second sub-trace 1213. The connection between one end of the first sub-trace 1211 away from the source end 111a and one end of the transition trace 1212 is located at the upper part of the first via 111; the connection between the other end of the transition trace 1212 and one end of the second sub-trace 1213 is located at the lower part of the first via 111.

[0035] The connection between the other end of the second sub-trace 1213 and one end of the second transition trace 1212 is located at the lower part of the second via 112; the connection between the other end of the second transition trace 1212 and one end of the second first sub-trace 1211 is located at the upper part of the second via 112.

[0036] The connection between the other end of the first sub-trace 1211 and one end of the third transition trace 1212 is located at the top of the third via, and the connection between the other end of the third transition trace 1212 and one end of the third second sub-trace 1213 is located at the bottom of the third via.

[0037] The connection between the other end of the third second sub-router 1213 and one end of the fourth transition route 1212 is located at the bottom of the fourth via; the connection between the other end of the fourth transition route 1212 and one end of the fourth second sub-router 1213 is located at the top of the fourth via.

[0038] The first sub-trace 1211, the transition trace 1212, and the second sub-trace 1213 are sequentially connected until the connection between the Nth first sub-trace 1211 and the Nth transition trace 1212 is located at the top of the Nth via 11N, and the Nth first sub-trace 1211 is connected to the terminal 111b.

[0039] By distributing a plurality of first sub-traces 1211 on the first surface 11a of the substrate 11, a plurality of transition traces 1212 distributed on the Nth via 11N, and a plurality of second sub-traces 1213 distributed on the second surface 11b, the inductance value of the NFC antenna 10 is the sum of the inductance values ​​of the plurality of first sub-traces 1211, the plurality of transition traces 1212 distributed on the Nth via 11N, and the plurality of second sub-traces 1213 distributed on the second surface 11b on the substrate 11. In this way, the inductance value is compensated by vias, the trace body 121 is shortened on the first surface 11a and the second surface 11b, thereby reducing the number of turns of the coil 12 on the first surface 11a and the second surface 11b, and thus reducing the overall size of the substrate 11.

[0040] In one specific embodiment, the plurality of first sub-routes 1211, the plurality of transitional routes 1212, and the plurality of second sub-routes 1213 in the aforementioned routing body 121 can be arranged in segments. Alternatively, the plurality of first sub-routes 1211, the plurality of transitional routes 1212, and the plurality of second sub-routes 1213 in the aforementioned routing body 121 can be arranged as a whole.

[0041] A via parasitic inductance is formed between the substrate 11, the vias, and the several transition traces 1212. The formula for the via parasitic inductance is as follows. L via = 5.08h[ln(4h / d)+1]. Where, L via Let h be the parasitic inductance of the via, d be the length of the via, and d be the diameter of the via. The parasitic inductance value of the via is directly proportional to the thickness of the substrate 11 and inversely proportional to the diameter of the via. As can be seen from the above formula for parasitic inductance of the via, increasing the number of vias can effectively increase the inductance value of the NFC antenna 10 on the substrate 11, thereby reducing the length of the trace body 121 on the substrate 11.

[0042] For example, when the thickness of substrate 11 is 50 mil and the diameter of the via is 10 mil, the parasitic inductance of the via is approximately 1.015 nH, or about 1 nH.

[0043] In some embodiments, the coil 12 includes a plurality of wire loops 122. The wire loops 122 are arranged in a ring shape. The number of the Nth via 11N is n. n = L NFC / (2*l1*[ln(l1 / D1)-K]*N 1.8 +5.08h[ln(4h / d)+1]). Where, L NFC The required inductance value for the NFC antenna 10. The required inductance value for the NFC antenna 10 can be a specific value or a range of values, as long as it meets the requirements of the NFC antenna 10. In this embodiment, the required inductance value for the NFC antenna 10 can be greater than or equal to 0.8uH and less than or equal to 1.5uH. l1 is the length (cm) of one loop of the conductor 122. D1 is the width of the conductor loop 122. N is the number of loops of the conductor loop 122. h is the length of the via. d is the diameter of the via. The above K value varies depending on the shape of the conductor loop 122. When the conductor loop 122 is annular, K is 1.07. When the conductor loop 122 is rectangular, K is 1.47.

[0044] The required inductance value L of the NFC antenna 10 described above NFCThe length l1 of a single conductor loop 122, the width D1 of the conductor loop 122, the K value, the number of loops N, the length h of the via, and the diameter d of the via work together to limit the number of vias in the substrate 11, increase the parasitic inductance of the vias, reduce the overall size of the substrate 11, and reduce the number of layers in the substrate 11, thereby reducing costs. The number of vias can be around four hundred.

[0045] When the conductor ring 122 is arranged in a ring shape, the conductor ring 122 can be, but is not limited to, square, rectangular, rhomboid, circular, etc. Of course, in other embodiments, the coil 12 is distributed in a serpentine pattern through the aforementioned plurality of first sub-traces 1211, plurality of transition traces 1212 and plurality of second sub-traces 1213.

[0046] Continue reading Figures 1 to 5 In some embodiments, the spacing between adjacent vias is s = c / n. Here, c is the total length of the coil 12; n is the number of the Nth via 11N. This formula limits the spacing between adjacent vias, allowing for an increase in the number of vias while maintaining the processing capability of the substrate 11.

[0047] Specifically, the spacing between adjacent vias is greater than or equal to 0.2 mm. The spacing between adjacent vias can be, but is not limited to, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, etc. By limiting the range of distances between adjacent vias, it is necessary not only to meet the inductance requirements of the NFC antenna 10, but also to meet the processing capabilities of the substrate 11.

[0048] The distance between adjacent vias can be the same or different. In this embodiment, for example, the distance between adjacent vias is the same, which facilitates processing. When the distance between adjacent vias is different, the distance can be irregular or regular. When the distance between adjacent vias is irregular, the distance can be any value, as long as it satisfies the requirement that the distance between adjacent vias is greater than or equal to 0.2mm. When the distance between adjacent vias is regular, the distance can be increased or decreased, etc., and is not limited here.

[0049] In some embodiments, the via diameter is greater than or equal to 0.2 mm and less than or equal to 0.3 mm. The via diameter can be, but is not limited to, 0.2 mm, 0.21 mm, 0.23 mm, 0.25 mm, 0.27 mm, 0.28 mm, 0.3 mm, etc. By limiting the via diameter, the aperture ratio of the single-layer processed substrate 11 can be guaranteed.

[0050] In some embodiments, the number of turns of the wire loop 122 is greater than or equal to 2 and less than or equal to 5. The number of turns of the wire loop 122 can be, but is not limited to, 2 turns, 2.5 turns, 3 turns, 3.5 turns, 4 turns, 4.5 turns, and 5 turns. By limiting the number of turns of the wire loop 122, the size of the substrate 11 can be reduced, thereby reducing the size of the NFC antenna 10, etc.

[0051] In this embodiment, the wire loop 122 has two turns, which not only reduces the size of the substrate 11, but also reduces the coupling coefficient between the NFC antenna 10 and the near-field contactless smart card. The less the NFC antenna 10 is affected by different near-field contactless smart card antennas, the better the adaptability of the NFC antenna 10 is.

[0052] In some embodiments, the width of the conductor loop 122 is greater than or equal to 0.25 mm and less than or equal to 1 mm. The width of the conductor loop 122 can be, but is not limited to, 0.25 mm, 0.3 mm, 0.35 mm, 0.42 mm, 0.54 mm, 0.65 mm, 0.74 mm, 0.87 mm, 0.93 mm, and 1 mm. By limiting the width of the conductor loop 122, the stability of the wiring body 121 can be improved while ensuring the inductance value requirements of the NFC antenna 10 are met.

[0053] In some embodiments, the thickness of the substrate 11 along the first direction is greater than or equal to 1.2 mm and less than or equal to 2.0 mm. The first direction is the direction from the first surface 11a to the second surface 11b. The thickness of the substrate 11 along the first direction can be, but is not limited to, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.9 mm, 1.9 mm, and 2 mm. By limiting the thickness of the substrate 11 along the first direction, the aperture ratio of the single-layer via processing of the substrate 11 can be guaranteed.

[0054] The coil 12 described above can be a copper coil. The first surface 11a and the second surface 11b are insulated from each other. When the substrate 11 is a PCB board, the front side of the PCB is the first surface 11a; the back side of the PCB is the second surface 11b. The PCB board described above can be a rigid board or a flexible board, etc., and is not limited thereto.

[0055] Continue reading Figures 1 to 5 This application provides an NFC communication device. The NFC communication device (not shown in the figure) includes the NFC antenna 10 described above. It should be noted that the NFC antenna 10 in this embodiment is the same as the NFC antenna 10 described in the above embodiments, and will not be repeated here.

[0056] By using the aforementioned NFC antenna 10, the NFC communication device can not only compensate for the inductance value through vias and shorten the trace length of the trace body 121 on the first surface 11a and the second surface 11b, thereby reducing the number of turns of the coil 12 on the first surface 11a and the second surface 11b, and thus reducing the overall size of the substrate 11, thereby reducing the size of the NFC communication device; it can also reduce the number of layers on the substrate 11, thereby reducing the cost of the NFC communication device. The aforementioned NFC communication device can be, but is not limited to, a time clock, a card reader, and an access control system.

[0057] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of those features. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications will change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. A process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0058] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An NFC antenna, characterized in that, include: The substrate includes a first surface and a second surface disposed opposite to each other. The first surface is provided with a source end and a terminal end. The substrate is provided with a first via, a second via, and up to an Nth via. The coil includes a trace body, with a trace start end and a trace end end at each end. The trace start end is connected to the source end. The trace body passes through the first via, the second via, and up to the Nth via in sequence. The trace end is connected to the terminal.

2. The NFC antenna according to claim 1, characterized in that, The trace body includes a plurality of first sub-traces, a plurality of transition traces, and a plurality of second sub-traces. The plurality of first sub-traces are located on the first surface, the plurality of transition traces are located in different vias, and the plurality of second sub-traces are located on the second surface. A first sub-trace, a transition trace, and a second sub-trace are connected in sequence. The connection between one end of the first sub-trace away from the source end and one end of the transition trace is located above the first via. The connection between the other end of the transition trace and one end of the second sub-trace is located below the first via. This continues until the connection between N first sub-traces and N transition traces is located above the Nth via. N first sub-traces are connected to the terminal.

3. The NFC antenna according to claim 2, characterized in that, The coil includes several wire loops arranged in a ring shape; the number of the Nth via is n, n = LNFC / (2*l1*[ln(l1 / D1)-K]*N1.8+5.08h[ln(4h / d)+1]); where LNFC is the inductance value required for the NFC antenna; l1 is the length of one loop of the wire loop in cm; D1 is the width of the wire loop; N is the number of loops; h is the length of the via; and d is the diameter of the via.

4. The NFC antenna according to claim 3, characterized in that, The spacing between adjacent vias is s = c / n; where c is the total length of the coil; and n is the number of the Nth via.

5. The NFC antenna according to claim 4, characterized in that, The spacing between adjacent vias is greater than or equal to 0.2 mm.

6. The NFC antenna according to claim 3, characterized in that, The diameter of the via is greater than or equal to 0.2 mm and less than or equal to 0.3 mm.

7. The NFC antenna according to claim 3, characterized in that, The number of wire loops is greater than or equal to 2 and less than or equal to 5.

8. The NFC antenna according to claim 3, characterized in that, The width of the conductor loop is greater than or equal to 0.25 mm and less than or equal to 1 mm.

9. The NFC antenna according to claim 3, characterized in that, The thickness of the substrate along the first direction is greater than or equal to 1.2 mm and less than or equal to 2.0 mm; wherein, the first direction is the direction from the first surface to the second surface.

10. An NFC communication device, characterized in that, Includes the NFC antenna as described in any one of claims 1 to 9.

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