Antenna device and electronic equipment

Abstract

The invention provides an antenna device and electronic equipment. A radiating body of the antenna device is provided with gaps to form a plurality of radiating branches, one radiating branch is provided with a feeding point, the other radiating branch is provided with connecting points, and the connecting points pass through a capacitor and / or are connected with a floor. According to the antenna device, the length of the radiator can be increased by arranging the gaps to increase the radiation branches, and when the length of the radiator or the number of the gaps is increased, the frequency of the antenna device is kept unchanged by shortening the length of the radiation branches provided with the feeding points. According to the optimized antenna device, under the condition that the working frequency is kept unchanged, the distance between the SAR hot areas generated by the antenna device can be increased by prolonging the radiating body. Furthermore, connection points are arranged on the radiation branches, so that the electric field distribution of the antenna device can be adjusted, and the SAR hot area is horizontally spread to reduce the amplitude of the SAR hot area.

Description

Technical Field

[0001] The present application relates to the field of antenna technology, and in particular to an antenna device and an electronic device. Background Art

[0002] When an electronic device realizes a communication function through an antenna device, the antenna device will radiate electromagnetic waves to the surroundings. When a human body is close to the antenna device, it is in the radiation field of the antenna device.

[0003] How to design antenna devices in electronic devices to reduce radiation to the human body is an urgent problem to be solved. Summary of the invention

[0004] The present application provides an antenna device and an electronic device. While keeping the antenna operating frequency unchanged, the distance between each SAR hot zone generated by the antenna device can be extended by extending the radiator. Furthermore, setting a connection point on the radiation branch can adjust the electric field distribution of the antenna device, thereby flattening the SAR hot zone horizontally to reduce the amplitude of the SAR hot zone.

[0005] In a first aspect, the present application provides an electronic device, comprising a wire antenna, which comprises a linear radiator, on which a feeding point is provided, and the two ends of the linear radiator are open; a gap is provided on the linear radiator, and the gap divides the linear radiator into a plurality of radiating branches; the length of the linear radiator is greater than L1, and the length of the central radiating branch of the linear radiator is less than L1, and the central radiating branch refers to the radiating branch between the two gaps closest to the feeding point on both sides of the feeding point; wherein L1 is the length of the radiator of the reference wire antenna, and the two ends of the middle feeding of the reference wire antenna are open; the operating frequency of the wire antenna is the same as the operating frequency of the reference wire antenna; in the linear radiator, a first side of the feeding point has a current distributed in a first direction along the linear radiator, and a second side of the feeding point has a current distributed in a second direction along the linear radiator, and the first side is opposite to the second side, and the first direction is opposite to the second direction.

[0006] It can be seen that the antenna device provided by the present application can extend the antenna radiator by opening a gap on the radiator to couple more radiation branches, thereby making the SAR hot zone generated by the antenna radiator farther away. Moreover, while extending the length of the radiator, the antenna operating frequency can be maintained unchanged by shortening the length of the central radiation branch. In other words, the longer the antenna radiator, the shorter the distance between the two gaps closest to the feeding point on both sides of the radiator.

[0007] In combination with the electronic device provided in the first aspect, the feeding point is specifically arranged in the middle of the linear radiator.

[0008] In combination with the electronic device provided in the first aspect, the same number of the slots are respectively provided on both sides of the feeding point.

[0009] In combination with the electronic device provided in the first aspect, the outer side of the slot of the linear radiator is connected to the floor via a capacitor and / or an inductor, and the outer side of the slot refers to a side away from the feeding point.

[0010] In combination with the electronic device provided in the first aspect, the outer side of the outermost slot of the linear radiator is connected to the floor via a capacitor and / or an inductor, and the outer side of the slot refers to a side away from the feeding point.

[0011] In this way, the electric field distribution of the antenna can be adjusted, the outermost tangential electric field can be weakened, a more uniform normal electric field can be constructed, and the SAR amplitude can be reduced.

[0012] In combination with the electronic device provided in the first aspect, the floor comprises: a printed circuit board PCB floor of the electronic device and a metal middle frame of the electronic device.

[0013] In combination with the electronic device provided in the first aspect, the electronic device includes a metal frame, and the linear radiator is formed by a portion of the metal frame of the electronic device.

[0014] In combination with the electronic device provided in the first aspect, the gap is formed by cutting along a first path on the metal frame, and the first path is a non-linear path.

[0015] In combination with the electronic device provided in the first aspect, the gap formed by cutting along the first path is a cross-toe coupling structure.

[0016] In combination with the electronic device provided in the first aspect, a radiation sheet is covered on the gap of the linear radiator, and a non-metallic material coating is provided between the radiation sheet and the linear radiator. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the electronic device on which the antenna design provided in this application is based;

[0018] Figure 2 It is a schematic diagram of analyzing the radiation situation of the antenna device provided in this application to the human body;

[0019] Figure 3A-3B It is a schematic diagram of the structure and equivalent circuit of a CM wire antenna provided by the present application;

[0020] Figure 4A-4B It is a structural and equivalent circuit diagram of a first-order coupled CM wire antenna provided by the present application;

[0021] Figure 5A-Figure 5BIt is a schematic diagram of the structure and equivalent circuit of a multi-order coupled CM wire antenna provided by the present application;

[0022] Figure 6 It is a schematic diagram of SAR simulation results of several CM wire antennas provided in this application;

[0023] Figure 7A-7B It is a structural and equivalent circuit diagram of a first-order coupled ground-back CM wire antenna provided by the present application;

[0024] Fig. 8A It is the comparison result of the electric field distribution before and after adding the return point of the CM wire antenna provided by the present application;

[0025] Figure 8B It is the comparison result of the electric field entering the human body before and after the CM wire antenna provided by the present application increases the capacitance value of the return point;

[0026] Figure 8C This is the SAR comparison result of the CM wire antenna provided by this application before and after adding the return point;

[0027] Figure 9A-9B Several coupling capacitor implementations are provided in this application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be described clearly and in detail below with reference to the accompanying drawings.

[0029] The technical solution provided in this application is applicable to electronic devices that adopt one or more of the following communication technologies: Bluetooth (BT) communication technology, global positioning system (GPS) communication technology, wireless fidelity (Wi-Fi) communication technology, global system for mobile communications (GSM) communication technology, wideband code division multiple access (WCDMA) communication technology, long term evolution (LTE) communication technology, 5G communication technology, SUB-6G communication technology and other future communication technologies, etc. In this application, the electronic device can be a mobile phone, a tablet computer, a personal digital assistant (PDA), etc.

[0030] Among them, in the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In the following, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more.

[0031] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0032] The antenna device in the electronic device will generate an electromagnetic field and radiate electromagnetic waves to the surroundings. When the human body is close to the antenna device, the human body is in the radiation field of the antenna device.

[0033] The radiation generated by the antenna device to the human body can be characterized by the specific absorption rate (SAR). SAR defines the electromagnetic radiation energy absorbed by a unit mass of biological tissue per unit time, or the electromagnetic radiation power absorbed by a unit mass of biological tissue.

[0034] SAR can be calculated according to the following formula (1-1):

[0035]

[0036] Wherein, dt represents unit time, dm represents unit mass, dW represents absorbed electromagnetic wave energy, and the unit of SAR is watt / kilogram (W / kg).

[0037] SAR can also be calculated according to the following formula (1-2):

[0038]

[0039] Where E represents the effective value of the electric field strength in biological tissue, σ represents the conductivity of biological tissue, and ρ represents the density of biological tissue.

[0040] International organizations and different countries have regulatory limits for SAR values. Electronic devices that exceed the SAR regulatory limits are prohibited from entering the market. Since SAR is proportional to the transmission power, for every 1dB change in transmission power, theoretically, SAR will also change by 1dB. Therefore, the method of reducing transmission power can be used to achieve the purpose of reducing SAR. However, reducing transmission power will also affect the emissivity of electronic equipment, thereby reducing the wireless communication quality of electronic equipment.

[0041] In order to solve the aforementioned problems, the present application optimizes the antenna design in the electronic device to achieve the purpose of both ensuring the wireless communication quality of the electronic device and reducing the SAR. Specifically, the SAR hot zone is extended by extending the radiator of the antenna device. And by setting a connection point grounded by a capacitor and / or an inductor on the radiator to adjust the electric field distribution of the radiator, the SAR hot zone is flattened laterally to reduce the amplitude of the SAR hot zone. In addition, in order to ensure that the operating frequency of the antenna remains unchanged after the radiator is extended, it is necessary to open a gap on the radiator to form a plurality of radiation branches, and the longer the length of the radiator or the more gaps are opened, the shorter the length of the radiation branch with a feeding point on the radiator is, so as to ensure that the operating frequency of the antenna remains unchanged.

[0042] In summary, the improved antenna of the present application has a longer radiator length compared to the reference antenna, thereby bringing about the effect of reducing SAR while maintaining the operating frequency. That is to say, in the case where the radiator of the reference antenna does not have a gap, if the length of the radiator of the reference antenna is L1, the length of the radiator of the improved antenna is greater than L1, and the length of the central radiating branch of the radiator of the improved antenna is less than L1. Alternatively, in the case where the radiator of the reference antenna has a gap, if the length of the radiator of the reference antenna is L1, and the length of the central radiating branch of the radiator of the reference antenna is L2, the length of the radiator of the improved antenna is greater than L1, and the length of the central radiating branch of the radiator of the improved antenna is less than L2. Among them, other parameters of the improved antenna and the reference antenna, such as antenna width, thickness clearance, etc., remain unchanged.

[0043] Next, the antenna design scheme and the improved antenna device provided in the present application are described in detail with reference to the accompanying drawings.

[0044] Figure 1 The schematic diagram of the structure of the electronic device on which the antenna design provided in the present application is based is exemplified.

[0045] like Figure 1 As shown, the electronic device 10 may include: a glass cover plate 13 , a display screen 15 , a printed circuit board (PCB) 17 , a housing 19 and a back cover 21 .

[0046] The glass cover plate 13 may be disposed close to the display screen 15 , and may be mainly used to protect the display screen 15 from dust.

[0047] Among them, PCB17 can adopt FR-4 dielectric board, Rogers dielectric board, mixed dielectric board of Rogers and FR-4, etc. Here, FR-4 is a code for a flame retardant material grade, and Rogers dielectric board is a high-frequency board. A metal layer can be set on the side of the printed circuit board PCB17 close to the shell 19, and the metal layer can be formed by etching metal on the surface of PCB17. The metal layer can be used for grounding the electronic components carried on PCB17 to prevent the user from electric shock or damage to the equipment. The metal layer can be called a PCB floor. In addition to the PCB floor, the electronic device 10 can also have other floors for grounding, such as a metal middle frame.

[0048] The housing 19 mainly supports the whole device. The housing 19 may include a peripheral conductive structure 11, which may extend around the periphery of the electronic device 10 and the display screen 15. Specifically, the peripheral conductive structure 11 may surround all or part of the four sides of the display screen 15 to help fix the display screen 15. In one implementation, the peripheral conductive structure 11 made of a metal material may be directly used as a metal frame of the electronic device 10 to form the appearance of a metal frame. In another implementation, a plastic frame may be further provided on the outer surface of the peripheral conductive structure 11 made of a metal material to form the appearance of a non-metal frame.

[0049] The back cover 21 may be a back cover made of a metal material, or a back cover made of a non-conductive material, such as a glass back cover, a plastic back cover or other non-metal back cover.

[0050] The inner side of the housing 19 is also provided with an antenna device 12, and the antenna device 12 can be connected to the PCB floor. In a possible implementation, the antenna device 12 can specifically use a metal frame in the housing 19 as an antenna.

[0051] Figure 1 Only some components included in the electronic device 10 are shown as examples, and the actual shapes, actual sizes, and actual structures of these components are not subject to Figure 1 limitation. Figure 1The position, size, etc. of the antenna device 12 shown in the figure are only a possible example. The present application does not specifically limit the position and size of the antenna device 12 in the electronic device 10. When the antenna device 12 is set at different positions in the electronic device 10, or the surrounding firmware of the antenna device 12 in the electronic device 10 is made of other materials, the ability of the electromagnetic waves generated by the antenna device 12 to penetrate various surfaces of the electronic device 10 will be different, and thus the radiation generated by the electronic device 10 to the human body in different directions will also be different.

[0052] refer to Figure 2 , Figure 2 This is a schematic diagram for analyzing the radiation situation of the antenna device provided in this application on the human body.

[0053] Figure 2 The antenna device 12 is located in the electronic device, for example, Figure 1 The electronic device 10 shown in FIG. 1 is located near the side elevation, that is, at the inner side of the housing 19 .

[0054] Figure 2 The peripheral firmware configuration of the antenna device 12 in the electronic device 10 shown includes, for example: the side elevation of the antenna device 12 is a plastic frame, the back is a metal back cover, and the front is a display screen and a glass cover.

[0055] Since electromagnetic waves can more easily pass through plastic materials than metal materials, the electromagnetic waves generated by the antenna device 12 can more easily penetrate the side surface (specifically, the side surface) of the electronic device 10. Figure 1-Figure 2 In other words, the SAR of the side elevation of the electronic device 10 is more likely to exceed the specified range. Therefore, it is necessary to reduce the SAR of the side elevation of the electronic device 10.

[0056] like Figure 2 As shown in the figure, the human body is a material with a high dielectric constant compared to air. The dielectric constant of the human body in air is expressed as ε 1 The dielectric constant of the human body is represented by ε 2 To express it, then ε 2 >ε 1 The electric field strength generated by the antenna device 12 on the side elevation is denoted by E 1 To express, then Ε 1 Specifically, it may include the normal component E n1 And tangential sharing t1 , the normal component Ε n1 It refers to the electric field component in the direction perpendicular to the side elevation (X direction), and the tangential component E t1 It refers to the electric field component in the direction parallel to the side elevation (z direction).

[0057] When a human body approaches the antenna device 12, the human body is 1 The electric field strength received under the action of 2 To express, then Ε 2 Specifically, it may include the normal component E n2 And tangential sharing t2 .

[0058] Among them, n2 and t2 It can be calculated by the following formula:

[0059] Ε n2 =(ε 1 / ε 2 ) n1 (2-1)

[0060] Ε t2 =Ε t1 (2-2)

[0061] According to the electromagnetic field boundary conditions, in the near field area of ​​the side elevation of the antenna device 12, the SAR generated by the antenna device 12 to the human body is mainly affected by the tangential electric field. This is because the human body is made of a material with a high dielectric constant and is difficult to absorb the normal electric field. When the near field characteristics of the side elevation of the antenna device 12 meet the following conditions, the SAR generated to the human body can be reduced:

[0062] (1) The side elevation electric field E of the antenna device 12 1 The main component is the normal component E n1 Mainly, this is because the human body is made of a material with a high dielectric constant and is difficult to absorb the normal electric field.

[0063] (2) The energy generated by the side elevation of the antenna device 12 is evenly distributed.

[0064] Therefore, the present application optimizes the antenna design, constructs a uniform normal electric field, extends the tangential electric field, and reduces the tangential component to achieve the purpose of reducing SAR.

[0065] It is understandable that since the SAR on the side elevation of the electronic device 10 is more likely to exceed the prescribed range, Figure 2 Only the radiation of the antenna device 12 on the side elevation of the electronic device 10 is analyzed. When the antenna device 12 is set at other positions in the electronic device 10, and when the surrounding firmware configuration of the antenna device 12 in the electronic device 10 is different, the SAR of the antenna device 12 on the back or front of the electronic device 10 may be higher, and the radiation of the antenna device 12 on the back or front of the electronic device 10 is mainly analyzed. The analysis principle is similar and will not be repeated here.

[0066] In the embodiment of the present application, the specific implementation form of the antenna device 12 can be designed based on a common mode (CM) wire antenna, a loop wire antenna, etc., or it can also be other types of antennas. The present application does not limit the antenna type.

[0067] Next, we will take the CM wire antenna as an example to specifically introduce the solution for optimizing antenna design provided by this application.

[0068] refer to Figure 3A-3B , Figure 3A-3B The structure and equivalent circuit diagram of a CM wire antenna provided in the present application are exemplified. Figure 3A-3B The antenna introduced is an implementation form of the reference antenna described in this application.

[0069] like Figure 3A As shown, the center of the antenna 101 is connected to a feeder, which is usually placed on a floor 103. The antenna 101 may be an implementation form of the antenna device 12 described in the present application, and the floor 103 may specifically be a PCB floor.

[0070] The directions of the currents in the antenna 101 are opposite on both sides of the center and are symmetrically distributed. The directions of the electric fields are in the same direction on both sides of the center and are symmetrically distributed. The currents at the feed 102 are distributed in the same direction. Based on the current distribution in the same direction at the feed 102, Figure 3A The feeding method shown can be called wire antenna CM feeding. Figure 3A The wire antenna pattern shown can be called CM wire antenna pattern. Figure 3A The current and electric field shown can be referred to as the current and electric field of the CM wire antenna mode, respectively.

[0071] The current and electric field of the CM line antenna mode are generated by the two horizontal branches on both sides of the center of the antenna 101 as a 1 / 4 wavelength antenna. The electric field of the antenna 101 is distributed tangentially at both ends.

[0072] like Figure 3B As shown, Figure 3B The circuit shown is the aforementioned Figure 3A The equivalent circuit corresponding to the antenna 101 shown in FIG. The gaps between the two ends of the antenna 101 and the ground are equivalent to capacitors C1 and C2 respectively, and the middle of the antenna 101 is indirectly fed.

[0073] Figure 3A-3B The content shown is only an example, and the present application does not limit the specific size of the antenna 101.

[0074] refer to Figure 4A-4B , Figure 4A-4B The structure and equivalent circuit diagram of a first-order coupled CM wire antenna provided by the present application are exemplified. Figure 4A-4B The antenna shown is an improved antenna of the present application.

[0075] like Figure 4A As shown, Figure 4A The antenna 201 is compared with Figure 3A For antenna 101 in the figure, the parameters of antenna width, thickness and clearance are the same, and two slits are opened on the radiator of antenna 201, dividing the radiator (also a linear radiator) into a first radiating branch, a second radiating branch and a third radiating branch. Specifically, a first slit is provided between the first radiating branch and the second radiating branch, that is, the first radiating branch and the second radiating branch are coupled through the first slit, and a second slit is also provided between the first radiating branch and the third radiating branch, that is, the first radiating branch and the third radiating branch are coupled through the second slit. Since one radiating branch is coupled at each end of the first radiating branch in the middle, the present application can also refer to antenna 201 as a first-order coupled CM linear antenna. Figure 3A Compared to the antenna 101 shown, Figure 4A The antenna 201 increases the total length of the radiator by adding radiating branches by opening a gap, and the first radiating branch in the antenna 201 is shorter than the only radiating branch in the antenna 101. This is because if the radiator is only extended without opening a gap, the operating frequency of the antenna is bound to decrease. The antenna can be equivalent to an LC circuit. In order to ensure that the operating frequency does not decrease, a gap needs to be opened (the equivalent capacitance of the gap is smaller than the infinite capacitance equivalent to the gap) to increase the operating frequency, and then further shorten the length of the first radiating branch (equivalent to reducing the inductance value), so as to achieve the purpose of maintaining the operating frequency of the antenna the same as that of the reference antenna.

[0076] Figure 4A A feeding point is provided at the center of the first radiating branch in the middle antenna 201 for connecting the feed, which is usually placed on the floor 103. The antenna 201 may be an implementation form of the antenna device 12 described in the present application, and the floor 103 may specifically be a PCB floor.

[0077] and Figure 3A The antenna 101 shown is similar, Figure 4A The current in the antenna 201 is opposite on both sides of the center and is symmetrically distributed. The electric field is in the same direction on both sides of the center and is symmetrically distributed. The electric field is tangentially distributed at both ends. The current at the feed 102 is distributed in the same direction. Based on the current distribution in the same direction at the feed 102, Figure 4A The feeding method shown can be called wire antenna CM feeding. Figure 4A The wire antenna pattern shown can be called a CM wire antenna pattern. Figure 4A The electric fields shown can be respectively referred to as the electric fields of the CM line antenna modes. Figure 4AIn the radiator shown, the left side / right side of the feeding point can be called the first side, and the right side / left side of the feeding point can be called the second side. A current in a first direction is distributed along the radiator on the first side of the feeding point, and a current in a second direction is distributed along the radiator on the second side of the feeding point.

[0078] Understandably, Figure 4A The current electric field distribution shown is for illustration only and should not constitute a limitation on the present application. In addition, the feeding point may also be set at a non-center of the radiator. When the feeding point is set at a non-center, the current on both sides of the feeding point on the radiator is not symmetrically distributed. The embodiment of the present application does not impose specific restrictions on the position of the feeding point. In addition, the number of gaps on both sides of the feeding point may be the same or different, that is, the radiating branches may also be symmetrical or asymmetrical. When the radiating branches on both sides of the feeding point are asymmetrical, the current on both sides of the feeding point on the radiator is not symmetrically distributed.

[0079] By comparison Figure 4A The antenna 201 is shown with Figure 3A As for the antenna 101, since the antenna 201 has a longer radiating body than the antenna 101 after adding the radiating branches, the tangential electric field distance of the tangential distribution at both ends is extended, and the distance between the SAR hot zones is also extended. For details, please refer to the following description of Figure 6 Description of the simulation results shown.

[0080] like Figure 4B As shown, Figure 4B The circuit shown is the aforementioned Figure 4A The equivalent circuit corresponding to the antenna 201 shown is as follows. The second radiation branch on the end side of the antenna 201 is equivalent to being connected to the floor 103 via a capacitor C3, the first gap between the first radiation branch and the second radiation branch is equivalent to a capacitor C4, the second gap between the first radiation branch and the third radiation branch of the antenna 201 is equivalent to a capacitor C5, and the third radiation branch on the end side is equivalent to being connected to the floor 103 via a capacitor C6.

[0081] Figure 4A-4B It is only introduced that the antenna radiator is lengthened by coupling a radiating branch at both ends of the middle radiating branch. In addition, the length of the radiator can be increased by coupling more radiating branches. Next, a multi-order coupled CM wire antenna formed by adding more radiating branches at both ends of the middle branch is introduced. The embodiments of the present application do not limit the added radiating branches.

[0082] refer to Figure 5A-Figure 5B , Figure 5A-Figure 5B The structure and equivalent circuit diagram of a multi-order coupled CM wire antenna provided by the present application are exemplified.

[0083] like Figure 5A As shown, Figure 5A The antenna 301 is compared with Figure 4A For antenna 301 in the figure, the parameters of antenna width, thickness and clearance are the same, and more slots are opened on the radiator (also a linear radiator), for example, 4 slots are opened, thereby dividing the radiator into 5 radiating branches. Specifically, it includes: a third slot is provided between the second radiating branch and the fourth radiating branch, that is, the second radiating branch and the fourth radiating branch are coupled through the third slot, and a fourth slot is provided between the third radiating branch and the fifth radiating branch, that is, the third radiating branch and the fifth radiating branch are coupled through the fourth slot. Since two radiating branches are coupled at both ends of the first radiating branch in the middle, the present application can also refer to antenna 301 as a second-order coupled CM linear antenna. Figure 4A Compared to the antenna 201 shown, Figure 5A Antenna 301 increases the total length of the radiator by continuing to add radiating branches, and the first radiating branch in antenna 301 is shorter than the first radiating branch in antenna 201. This is because when the radiator is lengthened by adding radiating branches, the operating frequency of the antenna will decrease. In order to keep the operating frequency of the antenna unchanged, the first radiating branch in antenna 301 needs to be further shortened.

[0084] Figure 5A A feeding point is provided at the center of the first radiating branch in the middle antenna 301 for connecting the feed, which is usually placed on the floor 103. The antenna 301 may be an implementation form of the antenna device 12 described in the present application, and the floor 103 may specifically be a PCB floor.

[0085] Figure 5A The current in the antenna 301 is opposite on both sides of the center and is symmetrically distributed. The electric field is in the same direction on both sides of the center and is symmetrically distributed. The current at the feed 102 is distributed in the same direction. Based on the current distribution in the same direction at the feed 102, Figure 5A The feeding method shown can be called wire antenna CM feeding. Figure 5A The wire antenna pattern shown can be called a CM wire antenna pattern. Figure 5A The electric fields shown can be respectively referred to as the electric fields of the CM line antenna modes.

[0086] Understandably, Figure 5AThe current electric field distribution shown is for illustration only and should not constitute a limitation on the present application. In addition, the feeding point may also be set at a non-center of the radiator. When the feeding point is set at a non-center, the current on both sides of the feeding point on the radiator is not symmetrically distributed. The embodiment of the present application does not impose specific restrictions on the position of the feeding point. In addition, the number of gaps on both sides of the feeding point may be the same or different, that is, the radiating branches may also be symmetrical or asymmetrical. When the radiating branches on both sides of the feeding point are asymmetrical, the current on both sides of the feeding point on the radiator is not symmetrically distributed.

[0087] By comparison Figure 5A The antenna 301 is shown with Figure 4A As for the antenna 301, since the antenna 301 has a longer radiator length than the antenna 201 after adding the radiation branch, the tangential electric field distance of the tangential distribution at both ends is extended, and then the distance between the SAR hot zones is also extended. For details, please refer to the following Figure 6 Description of the simulation results shown.

[0088] like Figure 5B As shown, Figure 5B The circuit shown is the aforementioned Figure 5A The equivalent circuit corresponding to the antenna 301 shown. The fourth radiation branch on the end side of the antenna 301 is equivalent to being connected to the floor 103 through a capacitor C7, the third gap between the fourth radiation branch and the second radiation branch is equivalent to a capacitor C8, and the first gap between the second radiation branch and the first radiation branch is equivalent to a capacitor C9. The second gap between the first radiation branch and the third radiation branch of the antenna 201 is equivalent to a capacitor C10, the fourth gap between the third radiation branch and the fifth radiation branch is equivalent to a capacitor C11, and the fifth radiation branch on the end side is equivalent to being connected to the floor 103 through a capacitor C12.

[0089] It is understandable that, in addition to lengthening the antenna radiator by coupling more radiating branches, the antenna radiator can also be lengthened directly by lengthening the length of the existing radiating branches. The present application does not limit the method of lengthening the radiator, as long as the distance of the tangential electric field is increased.

[0090] The previous article only uses 3 radiating branches and 5 radiating branches as examples to introduce the improved antenna device provided by the present application. In addition, the improved antenna device of the present application may include N radiating branches, and the improvement method is similar, that is, the longer the radiator is or the more radiating branches there are, the shorter the central radiating branch is. The central radiating branch refers to the radiating branch between the two gaps closest to the feeding point on both sides of the feeding point on the radiator, where N>1.

[0091] Figure 6 It is a schematic diagram of SAR simulation results of several CM wire antennas provided in this application.

[0092] Figure 6 The SAR simulation results shown in (a) are obtained by testing an antenna with a radiator length of 22.4 mm (e.g. Figure 3A Specifically, 10g of human tissue is placed close to the side surface of the antenna 101, which is equivalent to a distance of 0mm between the human tissue and the side surface of the antenna 101, and the SAR generated by the antenna 101 to the human body is measured. Figure 6 (a) contains two SAR hotspots, corresponding to Figure 3A There are two tangential electric field regions in the image. This is because the tangential electric field is more easily received by the human body than the normal electric field. Figure 3A When the radiator length of the antenna 101 is shorter, the distance between the two SAR hot zones obtained by simulation is also closer, for example, about 22.4 mm.

[0093] Figure 6 The SAR simulation results shown in (b) are obtained by testing an antenna with a radiator length of 39.4 mm (e.g. Figure 4A Specifically, SAR generated by the antenna 201 to the human body is obtained by using 10g of human tissue to cling to the side surface of the antenna 201, which is equivalent to a distance of 0mm between the human tissue and the side surface of the antenna 201, and measuring the SAR generated by the antenna 201 to the human body. Figure 6 (b) in the figure also contains two SAR hotspots, corresponding to Figure 4A There are two tangential electric field regions in the figure. This is because the tangential electric field can easily enter the human body. Figure 4A In the case where the radiator length of the antenna 201 is long, the distance between the two SAR hotspots obtained by the corresponding simulation is also extended, for example, to about 39.4 mm. In this way, when the SAR hotspots are dispersed, it is not easy for the antenna 201 to generate two SAR hotspots in the user's body at the same time, but when the user is close to the antenna 201 in a large area, two SAR hotspots will still be generated in the user's body at the same time.

[0094] Figure 6 The SAR simulation results shown in (c) are obtained by testing an antenna with a radiator length of 51.4 mm (e.g. Figure 5A The antenna 301 shown may be Figure 4A Specifically, the SAR generated by the antenna 301 to the human body is obtained by using 10g of human tissue to cling to the side surface of the antenna 301, which is equivalent to a distance of 0mm between the human tissue and the side surface of the antenna 301, and measuring the SAR generated by the antenna 301 to the human body. Figure 6 (c) in the figure also contains two SAR hotspots, corresponding to Figure 5AThere are two tangential electric field regions in the figure. This is because the tangential electric field can easily enter the human body. Figure 5A When the radiator length of the antenna 301 is longer, the distance between the two SAR hotspots obtained by the corresponding simulation is also more dispersed, for example, about 51.4 mm. In this way, when the SAR hotspots are dispersed, it is not easy for the antenna 301 to generate two SAR hotspots in the user's body at the same time, but when the user is close to the antenna 301 in a large area, two SAR hotspots will still be generated in the user's body at the same time.

[0095] Through comparative analysis Figure 6 The simulation results shown in Table 1 can provide the following information.

[0096] Table 1

[0097]

[0098] Table 1 shows the SAR generated by CM wire antennas with different radiator lengths and different operating frequencies when 10g of human tissue is close to the antenna (spacing is 0mm). For example, the CM wire antenna with a radiator length of 22.4mm and a frequency of 2.4GHz has a normalized SAR of 0.66, the CM wire antenna with a radiator length of 39.4mm and a frequency of 2.4GHz has a normalized SAR of 0.53, and the CM wire antenna with a radiator length of 51.4mm and a frequency of 2.4GHz has a normalized SAR of 0.48. It can be seen that, while ensuring that the antenna operating frequency is constant, the longer the radiator, the smaller the SAR value. The data shown in Table 1 are only obtained from tests, and this application does not limit the specific values, and the specific values ​​should not constitute a limitation on this application.

[0099] In addition, although lengthening the antenna radiator can disperse the SAR hot zone, the frequency of the antenna will also be reduced if only the antenna radiator is lengthened. In order to ensure that the antenna frequency remains unchanged, the present application can also achieve the goal of maintaining the antenna frequency unchanged by setting the size of the coupling capacitor between the aforementioned radiating branches.

[0100] Figure 7A-7B The structure and equivalent circuit diagram of a first-order coupled ground-back CM wire antenna are exemplified.

[0101] like Fig. 7A As shown, Fig. 7A The antenna 401 is compared with Figure 4A For the antenna 201 in FIG. 1 , a return point G1 and a return point G2 are respectively provided on the two radiating branches on the end side. A capacitor and / or an inductor may be connected between the return point G1 on the second radiating branch and the floor 103. A capacitor and / or an inductor may also be connected between the return point G2 on the third radiating branch and the floor 103. For the rest of the introduction, please refer to the previous description of Figure 4A The description of is not repeated here.

[0102] The return points G1 and G2 mentioned in the present application refer to connection points, and the connection points can be connected to the floor through capacitors and / or inductors, etc., but are not directly grounded.

[0103] Fig. 7A Compared with the electric field distribution in Figure 4A For the electric field distribution in Fig. 7A Construct a relatively uniform normal electric field, that is, weaken the tangential electric field component on the end side and enhance the normal electric field component. Fig. 7A The electric field distribution shown is only an example and should not be construed as limiting the present application.

[0104] like Figure 7B As shown, Figure 7B The circuit shown is the aforementioned Fig. 7A The equivalent circuit corresponding to the antenna 401 shown in FIG. Figure 4B Compared to the circuit shown, Figure 7B In the circuit shown, return points G1 and G2 are respectively provided on the two radiating branches on the end side. The return point G1 on the second radiating branch is connected to a capacitor and then to ground. The return point G2 on the third radiating branch is connected to a capacitor and then to ground. For the rest of the introduction, please refer to the previous description of Figure 4A The description of is not repeated here.

[0105] Fig. 8A This is the comparison result of the electric field distribution before and after the CM wire antenna provided by the present application is added with a return point.

[0106] Fig. 8A The electric field distribution simulation results shown in (a) are obtained by testing the aforementioned antenna without a capacitor and / or inductor connected in series to ground (e.g. Figure 4A Since the antenna 201 is not connected in series with a capacitor and / or an inductor to return to the ground, the tangential electric field at both ends of the antenna 401 obtained by simulation is relatively strong.

[0107] Fig. 8A The electric field distribution simulation result shown in (b) is obtained by testing the antenna after the aforementioned series capacitor is connected (for example Fig. 7A Compared with antenna 201, antenna 401 has two radiating branches connected in series with capacitors and then returned to the ground, which has the effect of adjusting the electric field distribution of the antenna. Therefore, the tangential electric field at both ends of antenna 401 obtained by simulation will become weaker, and the normal electric field in the middle will become stronger accordingly. Compared with the tangential electric field, the normal electric field is difficult to be received by the human body.

[0108] Figure 8B This is a comparison result of the electric field entering the human body before and after the CM wire antenna provided by the present application increases the return capacitance value.

[0109] Figure 8B The electric field distribution simulation results shown in (a) are obtained by testing the aforementioned antenna without a capacitor and / or inductor connected in series to ground (e.g. Figure 4A Since the antenna 201 is not connected in series with a capacitor and / or an inductor to return to the ground, the tangential electric field at both ends of the antenna 401 obtained by simulation is relatively strong.

[0110] Figure 8B The electric field distribution simulation result shown in (b) is obtained by testing the antenna after the aforementioned series capacitor is connected (for example Fig. 7A Specifically, when the antenna 401 is connected in series with capacitors (e.g., C13=C14=3.5pF) on the two radiating branches on the end side, the electric field distribution of the antenna is adjusted after the capacitor is connected in series. Therefore, after the capacitor with a smaller capacitance value is connected in series, the tangential electric field at both ends of the antenna 401 entering the human body is simulated to be weakened, and the normal electric field in the middle is correspondingly strengthened.

[0111] Figure 8B The electric field distribution simulation result shown in (c) is obtained by testing the antenna after the aforementioned series capacitor is connected (for example Fig. 7A Specifically, when the antenna 401 is connected in series with capacitors (e.g., C13=C14=5pF) on the two radiating branches on the end side, the electric field distribution of the antenna is adjusted after the capacitors are connected in series. Therefore, after the capacitors with larger capacitance values ​​are connected in series, the tangential electric field at both ends of the antenna 401 entering the human body obtained by simulation will be further weakened, and the normal electric field in the middle will be further strengthened accordingly. Compared with the tangential electric field, the normal electric field is difficult to be received by the human body.

[0112] By comparison Figure 8B It can be seen from the simulation results shown in (a), (b) and (c) that, for the same antenna specification, when the end-side radiation branch of the antenna is provided with a return-to-ground capacitor, the electric field distribution of the antenna can be adjusted. Specifically, compared with not providing a return-to-ground capacitor on the end-side radiation branch, the tangential electric field on the end side can be weakened, and the normal electric field in the middle can be strengthened accordingly. Therefore, the tangential electric field on the end side entering the human body will be reduced, and the normal electric field in the middle entering the human body will be increased. Moreover, when return-to-ground capacitors of different sizes are provided on the end-side radiation branch of the antenna, the adjustment effect of the electric field distribution is different. Specifically, when the capacitance value of the return-to-ground capacitor is larger, the tangential electric field on the end side will be weaker, and the normal electric field in the middle will be stronger accordingly. Therefore, the tangential electric field on the end side entering the human body will be reduced, and the normal electric field in the middle entering the human body will be increased.

[0113] From the above analysis, we can know that in order to reduce the SAR entering the human body, it is necessary to adjust the electric field distribution of the antenna so that the electric field entering the end side is equivalent to the electric field entering the human body in the middle. Therefore, the return capacitance set on the end side radiation branch of the antenna cannot be too small or too large. When the return capacitance is too small, the tangential electric field is strong, and the tangential electric field on the end side is more likely to enter the human body, which will cause the electric field on the end side entering the human body to be too large. When the return capacitance is too large, the electric field in the middle is extremely strong. Although the normal electric field in the middle is not easy to enter the human body, it will still cause the electric field in the middle entering the human body to be too large.

[0114] Figure 8C This is the SAR comparison result of the CM wire antenna provided by the present application before and after adding the return point.

[0115] Figure 8C The SAR simulation results shown in (a) are obtained by testing an antenna with a radiator length of 39.4 mm (e.g. Figure 4A Since the antenna 201 is not connected in series with a capacitor and / or an inductor to return to the ground, the tangential electric field on the end side is strong, so there are SAR hotspots at both ends of the antenna 401 obtained by simulation, and the peak value of the SAR hotspot is large.

[0116] Figure 8C The SAR simulation results shown in (b) are obtained by testing an antenna with a radiator length of 39.4 mm (e.g. Fig. 7A The SAR generated by the antenna 401 shown in the figure on the human body is obtained. Since the antenna 401 has capacitors connected in series on the two radiating branches on the end side (for example, C13=C14=3.5pF), the tangential electric field on the end side is weakened and the normal electric field in the middle becomes stronger. Since the series connection of the capacitor has the effect of adjusting the electric field distribution of the antenna, after the capacitor with a smaller capacitance value is connected in series, there are SAR hot zones at both ends of the antenna 401 obtained by simulation that diffuse in the lateral direction, and the peak value of the SAR hot zone becomes smaller. It can be seen that diffusing the SAR hot zone distribution in the direction parallel to the human body (i.e. Figure 8C The lateral diffusion shown in the figure can reduce the peak value of the SAR hot spot in the direction perpendicular to the human body.

[0117] For antennas with the same radiator length but different sizes of ground return capacitors, the SAR generated by the antennas is different. For details, please refer to the information shown in Table 2 below.

[0118] Table 2

[0119]

[0120] Table 2 shows the SAR generated by CM wire antennas with the same radiator length and different ground return capacitance when 10g of human tissue is close to the antenna (spacing is 0mm). For example, the CM wire antenna with a radiator length of 51.4mm and a frequency of 2.4GHz has a normalized SAR of 0.49 when no ground return capacitance is set. For another example, the CM wire antenna with a radiator length of 51.4mm and a frequency of 2.4GHz has a normalized SAR of 0.40 when a 3.5pF ground return capacitance is set. It can be seen that when the length of the antenna radiator is constant, the SAR value of the antenna will decrease after the ground return capacitance is set. In the embodiment of the present application, after the ground return capacitance is set, not only can the SAR be reduced, but it can also be used to keep the frequency of the antenna unchanged after the radiator length is changed. The data shown in Table 2 are only obtained from tests, and the present application does not limit the specific values, and the specific values ​​should not constitute a limitation on the present application.

[0121] In the embodiment of the present application, the coupling capacitors between the radiation branches in the antenna (such as C1-C12 mentioned above) can be implemented by using lumped capacitors or distributed capacitors. The embodiment of the present application does not limit the specific implementation form of the capacitors.

[0122] Figure 9A-9B Several coupling capacitor implementations are provided in this application.

[0123] Fig.9A An example of an interdigital coupled distributed capacitor is shown. This interdigital coupled distributed capacitor is mainly designed for antennas of FPC implementation type and laser engraving antenna (LDS) implementation type. Because this type of antenna is thinner and has a small cross-sectional area, in order to ensure that the size of the coupling capacitor is sufficient, a non-linear gap needs to be set to increase the coupling contact surface. Specifically, when the antenna radiator adopts the metal frame of an electronic device, the metal frame can be cut along a non-linear first path, and the radiator after cutting can form an interdigital coupling structure at the gap. The coupling surface area between the radiating branches is increased by interdigital coupling to obtain a coupling capacitance of sufficient value. Fig.9A The specific form of the interdigital coupling shown is only an example, and the present application does not limit the interdigital form.

[0124] Fig. 9B The capacitance formed by the coupling of the radiating plate is shown as an example. Specifically, the radiating plate can be covered on the gap of the antenna radiator, and a non-metallic material coating is provided between the radiating plate and the radiator. This method is mainly for antennas with a fixed gap distance between radiating branches. When it is necessary to maintain the distance unchanged and increase the coupling capacitance, the radiating plate can be covered on the gap of the antenna radiating branch, so that the two radiating branches are coupled with the radiating plate respectively, which is equivalent to increasing the capacitance between the two radiating branches.

[0125] In summary, in the antenna device provided in the present application, the antenna radiator can be extended by opening a gap on the radiator to couple more radiating branches, thereby making the SAR hot zone generated by the antenna radiator be pulled further away. And a connection point is set on the radiating branch, and the connection point is connected to the floor through a capacitor and / or an inductor to adjust the electric field distribution of the antenna, construct a more uniform normal electric field, and thus reduce the SAR amplitude. In particular, while extending the length of the radiator, in order to maintain the antenna operating frequency unchanged, it is also necessary to shorten the length of the central radiating branch. In other words, the longer the antenna radiator, the shorter the distance between the two slits closest to the feeding point on both sides of the feeding point in the radiator.

[0126] It should be understood that each step in the above method embodiment provided by the present application can be completed by an integrated logic circuit of hardware in a processor or by instructions in the form of software. The method steps disclosed in the embodiments of the present application can be directly embodied as being executed by a hardware processor, or by a combination of hardware and software modules in a processor.

[0127] The present application also provides an electronic device, which may include: a memory and a processor, wherein the memory may be used to store a computer program; and the processor may be used to call the computer program in the memory so that the electronic device executes the method in any one of the above embodiments.

[0128] The present application also provides a chip system, which includes at least one processor for implementing the functions involved in the method executed by the electronic device in any of the above embodiments.

[0129] In one possible design, the chip system also includes a memory, which is used to store program instructions and data, and the memory is located inside or outside the processor.

[0130] The chip system may be composed of the chip, or may include the chip and other discrete devices.

[0131] Optionally, the processor in the chip system may be one or more. The processor may be implemented by hardware or by software. When implemented by hardware, the processor may be a logic circuit, an integrated circuit, etc. When implemented by software, the processor may be a general-purpose processor implemented by reading software code stored in a memory.

[0132] Optionally, the memory in the chip system may also be one or more. The memory may be integrated with the processor or may be separately arranged with the processor, which is not limited in the embodiments of the present application. Exemplarily, the memory may be a non-transient processor, such as a read-only memory ROM, which may be integrated with the processor on the same chip or may be arranged on different chips respectively. The embodiments of the present application do not specifically limit the type of memory and the arrangement of the memory and the processor.

[0133] Exemplarily, the chip system can be a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD) or other integrated chips.

[0134] The present application also provides a computer program product, which includes: a computer program (also referred to as code, or instruction), which enables a computer to execute the method executed by the electronic device in any of the above embodiments when the computer program is executed.

[0135] The present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program (also referred to as code or instruction). When the computer program is executed, the computer executes the method executed by the electronic device in any of the above embodiments.

[0136] The various implementation modes of the present application can be combined arbitrarily to achieve different technical effects.

[0137] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in this application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk SolidStateDisk), etc.

[0138] Those skilled in the art can understand that to implement all or part of the processes in the above-mentioned embodiments, the processes can be completed by computer programs to instruct related hardware, and the programs can be stored in computer-readable storage media. When the programs are executed, they can include the processes of the above-mentioned method embodiments. The aforementioned storage media include: ROM or random access memory RAM, magnetic disk or optical disk and other media that can store program codes.

[0139] In short, the above description is only an embodiment of the technical solution of the present invention, and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made according to the disclosure of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electronic device, characterized in that: The invention comprises a linear antenna, wherein the linear antenna comprises a linear radiator, a feeding point is arranged on the linear radiator, and both ends of the linear radiator are open; A gap is provided on the linear radiator, and the gap divides the linear radiator into a plurality of radiating branches; The length of the linear radiator is greater than L1, and the length of the central radiating branch of the linear radiator is less than L1, and the central radiating branch refers to the radiating branch between the two gaps closest to the feeding point on both sides of the feeding point; Wherein, L1 is the length of the radiator of the reference line antenna, the middle feed of the reference line antenna is open at both ends; the operating frequency of the line antenna is the same as the operating frequency of the reference line antenna; In the linear radiator, a current in a first direction is distributed along the linear radiator on a first side of the feeding point, and a current in a second direction is distributed along the linear radiator on a second side of the feeding point, the first side is opposite to the second side, and the first direction is opposite to the second direction.

2. The electronic device according to claim 1, characterized in that: The feeding point is specifically arranged in the middle of the linear radiator.

3. The electronic device according to claim 2, characterized in that: The same number of slots are respectively provided on both sides of the feeding point.

4. The electronic device according to any one of claims 1 to 3, characterized in that: The outer side of the slot of the linear radiator is connected to the ground via a capacitor and / or an inductor, and the outer side of the slot refers to a side away from the feeding point.

5. The electronic device according to any one of claims 1 to 4, characterized in that: The outer side of the outermost slot of the linear radiator is connected to the ground via a capacitor and / or an inductor, and the outer side of the slot refers to a side away from the feeding point.

6. The electronic device according to claim 4 or 5, characterized in that: The floor comprises: a printed circuit board PCB floor of the electronic device and a metal middle frame of the electronic device.

7. The electronic device according to any one of claims 1 to 6, characterized in that: The electronic device comprises a metal frame, and the linear radiator is formed by a part of the metal frame of the electronic device.

8. The electronic device according to claim 7, characterized in that: The slit is formed by cutting along a first path on the metal frame, and the first path is a non-linear path.

9. The electronic device according to claim 8, characterized in that: The gap cut along the first path is a cross-toe coupling structure.

10. The electronic device according to any one of claims 1 to 9, characterized in that: A radiation sheet is covered on the gap of the linear radiator, and a non-metallic material coating is arranged between the radiation sheet and the linear radiator.

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