CN103515704A - Near field communication antenna and electronic equipment - Google Patents

Abstract

The invention belongs to the antenna field and discloses a near field communication antenna. The near field communication antenna comprises an insulating substrate with a bearing surface, and a coil arranged on the bearing surface, wherein both ends of the coil form two feeding points; and the coil is partially provided with at least one magnetic piece. As the realization effects of the magnetic piece partially arranged on the coil are the same as that of a whole piece of magnetic piece, space can be effectively reduced and production cost is saved. The invention further discloses electronic equipment applying the near field communication antenna. Under the condition that the near field communication antenna can save space, there is enough space for accommodating other components, or the volume of the electronic equipment is reduced, and the production cost is saved.

Description

A near-field communication antenna and electronic equipment

technical field

The invention belongs to the field of antennas, and in particular relates to a near-field communication antenna and electronic equipment using the same.

Background technique

Near Field Communication (NFC, Near Field Communication) is a technology that uses electromagnetic induction to send and receive electromagnetic waves to realize short-distance wireless communication between electronic devices, and thus gave birth to electronic devices such as mobile phones with near-field payment functions. It has largely changed the way people use some everyday devices, especially credit cards, keys and cash.

In NFC antenna products of electronic equipment, especially in mobile phone NFC antennas, metal devices and external magnetic fields have a greater impact on NFC antennas, and it is usually necessary to add a whole piece of magnetic sheet (ferrite, wave-absorbing material) on the back of the antenna to Enhance the signal reception of the antenna and shield the influence of metal devices on the antenna. Since the area of the NFC antenna is usually relatively large, the cost of the magnetic sheet remains high, resulting in a very high cost of the entire antenna. Simultaneously, because the magnetic sheet has a certain thickness, it occupies more limited space. How to solve the deficiencies of the above-mentioned technologies is a problem expected to be solved in the field of NFC antennas at present.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, thereby providing a low-cost, small-occupancy near-field communication antenna and electronic equipment using the antenna.

In order to solve the above technical problems, the present invention provides the following technical solutions:

A near-field communication antenna, comprising: an insulating substrate with a bearing surface, a coil arranged on the bearing surface, two ends of the coil form two feeding points, and at least one piece of magnetic conduction is partially arranged on the coil piece.

The present invention also discloses an electronic device, which includes the above-mentioned near-field communication antenna.

Compared with the prior art, the present invention has the following beneficial effects: In the near-field communication antenna provided by the embodiment of the present invention, at least one magnetic conductive sheet is partially provided on the coil, and it has been verified by experiments that the magnetic conductive sheet is partially provided on the coil In the case of achieving the same effect as the whole magnetic sheet, it can effectively reduce the space occupied by the antenna, and it is more cost-effective to partially arrange the magnetic sheet on the coil than the whole magnetic sheet. Electronic equipment using the near-field communication antenna can have enough space to accommodate other components or reduce the volume of the electronic equipment while reducing the space occupied by the near-field communication antenna, while saving costs.

Description of drawings

FIG. 1 is a schematic structural diagram of a near-field communication antenna according to a first embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a near-field communication antenna according to a second embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a near-field communication antenna according to a third embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a near field communication antenna according to a fourth embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a near-field communication antenna according to a fifth embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a near-field communication antenna according to a sixth embodiment of the present invention.

Fig. 7 is a schematic diagram of the structure of each layer of the near field communication antenna according to the embodiment of the present invention.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The present invention discloses a near-field communication antenna. FIG. 1 to FIG. 6 are schematic structural views of the near-field communication antennas in six embodiments of the present invention. The near-field communication antenna includes: an insulating substrate 10 with a bearing surface, The two ends of the coil form two feeding points 21 , and at least one magnetically permeable sheet 50 is partly provided on the coil 20 .

After a large number of experiments, it can effectively reduce the space occupied by the antenna under the condition that the coil is partially equipped with a magnetic conductive sheet and the whole magnetic conductive sheet has the same effect. It is also more cost-effective than the film.

Taking the antenna size of 30mm*40mm as an example to carry out the test, the area of the magnetic sheet used to cover the entire antenna area is 1200 square millimeters, and the magnetic sheet used to partially cover the antenna area is 2 pieces of magnetic sheet as an example. The length of each sheet is 40mm, width 8mm, so the required area of the magnetic permeable sheet is 40*8*2=640 square millimeters, accounting for about 50% of the entire antenna area. Place the NFC antenna to be tested together with the mobile phone prototype in the EMV near-field magnetic field measurement system, place the mobile phone equipped with the NFC antenna at the center coordinates (0, 0, 0), and then modulate the device for testing. The test results are as follows:

The above data shows that it is not always believed that the larger the magnetic sheet, the more antenna area it covers, the better the test results. Partially provided with a magnetically conductive sheet on the coil has the same effect as the whole piece of magnetically conductive sheet, and both can pass the test. Moreover, the coil is partially provided with a magnetically conductive sheet, which can effectively reduce the space occupied by the antenna and save costs.

Generally, when the NFC antenna is working, since the metal device in the device used is in the NFC alternating magnetic field, the metal device will generate eddy currents, and these eddy currents will consume energy, resulting in detuning of the NFC antenna and reducing the quality of the antenna factor. At this time, we need to increase the magnetic guide sheet to reduce the influence of the metal device on the NFC antenna. The magnetic guide sheet can shield the metal device inside the electronic device (such as a mobile phone) from interfering with the performance of the NFC antenna, absorb unnecessary frequency bands and increase the magnetic flux of the coil. . Since the positions of the metal parts in the electronic equipment of each NFC antenna used are different, it will have a good effect to stick the magnetic conductive sheet on different positions in a targeted manner. On the other hand, the magnetic sheet itself will also have magnetic loss. When a large-area magnetic sheet covers the entire antenna area, the magnetic loss will be greater. Therefore, it is not the best effect to cover the entire antenna area with a magnetic sheet. It is necessary to paste a suitable magnetic conductive sheet locally.

In this embodiment, the coil 20 forms a rectangle on the bearing surface as an example for illustration:

The magnetically conductive sheet 50 shown in Fig. 1 is two sheets, and the magnetically conductive sheet 50 is strip-shaped, and the two strip-shaped magnetically conductive sheets 50 are respectively arranged on two opposite sides of the rectangle away from the feeding point 21 . Since the strip-shaped magnetically conductive sheet is relatively narrow, even the leftover material of the magnetically conductive sheet can be used, which improves the utilization rate of the magnetically conductive sheet to the greatest extent.

In FIG. 2 , the magnetically conductive sheet 50 is L-shaped, and the magnetically conductive sheet 50 is arranged in one corner of the rectangle away from the feeding point 21 . In another embodiment, the feed point 21 is set at a corner of the rectangle formed by the coil 20; the L-shaped magnetic sheet greatly improves the utilization rate of the magnetic sheet, and at the same time, the L-shaped The magnetically conductive sheet exerts the excellent performance of the antenna.

The L-shaped magnetically conductive sheet 50 can also be relatively large enough to cover three corners of the rectangle except the corner where the feeding point 21 is located, as shown in FIG. 3 . In order to balance the magnetic loss caused by the magnetic permeable sheet and the magnetic permeability enhanced by the magnetic permeable sheet to the coil antenna, experiments have proved that the covering effect of this magnetic permeable sheet is the best.

In other embodiments, there may also be two L-shaped magnetic conductive sheets, and the magnetic conductive sheets are arranged on two corners of the rectangle away from the feeding point, as shown in FIG. 4 and FIG. 5 . The L-shaped magnetically conductive sheet in FIG. 4 is relatively large, and the magnetically conductive sheet covers the other three sides except the side where the feeding point 21 is located. When the coverage area of the antenna is large, in order to effectively use the magnetic conductive sheet, it can be divided into two L-shaped magnetic conductive sheets, and the free area of the L-shaped magnetic conductive sheet can be reasonably used. As shown in FIG. 5 , the L-shaped magnetically conductive sheet 50 is relatively small, and the magnetically conductive sheet 50 only covers two opposite corners of the rectangle. Due to the impact of the structure, the antenna may cover a large area. On the premise of satisfying the antenna function, a pair of L-shaped magnetic conductive sheets are designed diagonally to reduce the cost of the magnetic conductive sheet.

In other embodiments, the magnetically conductive sheet 50 is U-shaped, and the magnetically conductive sheet is arranged on three sides of a rectangle away from the feeding point, as shown in FIG. 6 . U-shaped is the deformation of two L-shaped magnetic guides. When it is necessary to install magnetic guides at adjacent corners, in order to introduce the assembly process, one U-shaped magnetic guide can be used instead of two L-shaped guides. disk.

The following is the data obtained by testing the same Mini NFC antenna with different shapes of magnetic chips in the same mobile phone environment:

Since the above-mentioned embodiments of the present invention are partially mounted, that is, the coil is partially provided with a magnetic conductive sheet, which avoids unnecessary waste of magnetic sheets and greatly improves the utilization rate of materials. Under the premise of comparable performance , The disk saves more than 30% of the cost. When making magnetic sheets of different shapes and sizes, the size and shape of the magnetic sheet can be designed according to the actual application situation, and the required shape of the magnetic sheet can be locally attached to different positions in a targeted manner, so as to reduce the magnetic loss and make the Magnetic losses are minimized and efficiency is maximized. In a specific implementation, it can be cut into a desired shape by means of die-cutting, stamping, etc., and the magnetic sheet can be made by methods such as sintering and casting. The above embodiments can reduce the overall loss of the NFC antenna in the alternating magnetic field, thereby improving the communication function of the NFC antenna (increasing the communication distance).

Fig. 7 is a schematic diagram of the structure of each layer of the near field communication antenna according to the embodiment of the present invention. In this embodiment, the coil 20 can be made of copper, aluminum, silver paste or one of the above alloys through etching, printing, electroplating, chemical deposition and other processes, and a coating, such as ink and other insulating substances, is added to the surface to prevent wear or short circuit. The insulating substrate 10 adopts one of PI (polyimide, polymide), PET (polyethylene terephthalate, polyethylene terephthalate), and FR4. FR-4 is a code name for a flame-resistant material grade, which means that the resin material must be able to extinguish itself after a burning state. It is not a material name, but a material grade. Therefore, the current general circuit There are many types of FR-4 grade materials used in boards, but most of them are composite materials made of so-called four-functional epoxy resin plus filler (Filler) and glass fiber.

A solder resist layer 30 is also provided on the layer where the coil 20 is located, and the solder resist layer 30 can protect the circuits in the circuit layer from being oxidized, partially short-circuited, and prevented from being polluted. A magnetic conductive sheet 50 is disposed on the solder resist layer 30 . The magnetic conductive sheet 50 is fixed on the solder resist layer 30 through the first adhesive layer 40 . The first adhesive layer 40 can be adhesive substances such as glue or double-sided tape. The magnetic conductive sheet 50 can be ferrite, which is formed by casting or sintering of magnetic powder. Effect of materials on antennas. The side opposite to the bearing surface of the insulating substrate 10 can also be provided with a second adhesive layer 60, which can facilitate the antenna to be pasted on the required equipment.

Since the magnetic sheet is composed of easily magnetically conductive ferrite, and because the magnetic sheet is fragile, the larger the area, the lower the yield rate. Since the embodiment of the present invention uses a partial magnetic sheet, it can be covered on the surface of the magnetic sheet with a Layer protective film, wherein the protective film is composed of PI (Polyimide, polyimide), PET (Polyethylene terephthalate, polyterephthalic acid plastic) and other materials. It can protect the magnetic conductive sheet from being damaged.

The present invention also provides an electronic device, including the above-mentioned near-field communication antenna. Electronic equipment using the near-field communication antenna can have enough space to accommodate other components, or reduce the volume of the electronic equipment, and save costs when the near-field communication antenna reduces the occupied space. The electronic device is preferably a mobile phone. Of course, it may also be other electronic devices using near-field communication antennas.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (10)

1. A near-field communication antenna, comprising: an insulating substrate with a bearing surface, a coil arranged on the bearing surface, two ends of the coil form two feeding points, and it is characterized in that the coil is partially At least one magnetically conductive sheet is provided. 2 . The near field communication antenna according to claim 1 , wherein the coil forms a rectangle on the bearing surface. 3 . 3. The near-field communication antenna according to claim 2, characterized in that, the magnetically conductive sheet is two pieces, the magnetically conductive sheet is strip-shaped, and the two strip-shaped magnetically conductive sheets are respectively arranged in a rectangular space away from On two opposite sides of the feed point. 4 . The near field communication antenna according to claim 2 , wherein the magnetic conductive sheet is L-shaped. 5 . The near field communication antenna according to claim 4 , wherein the magnetically conductive sheet is one piece, and the magnetically conductive sheet is arranged on a corner of the rectangle away from the feeding point. 6 . 6 . The near field communication antenna according to claim 4 , wherein there are two magnetically conductive sheets, and the magnetically conductive sheets are arranged on two corners of the rectangle away from the feeding point. 7 . 7 . The near field communication antenna according to claim 2 , wherein the magnetically conductive sheet is U-shaped, and the magnetically conductive sheet is arranged on three sides of a rectangle away from the feeding point. 8. The near field communication antenna according to any one of claims 1-7, wherein a solder resist layer is further disposed on the layer where the coil is located, and the magnetically conductive sheet is disposed on the solder resist layer. 9. An electronic device, comprising the near field communication antenna according to any one of claims 1-8. 10. The near field communication antenna according to claim 9, wherein the electronic device is a mobile phone.

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