Antennas and foldable electronic devices

Abstract

The embodiment of the present application provides an antenna and a foldable electronic device, the foldable electronic device comprises a rotating shaft, a first main body and a second main body, the antenna comprises a first radiator and a second radiator, the first radiator is arranged in the first main body, the second radiator is arranged in the second main body, the first radiator and the second radiator are grounded at the rotating shaft, the first radiator inputs an electric signal through a first feeding point, the second radiator inputs an electric signal through a second feeding point, the first feeding point and the second feeding point are connected through a radio frequency connecting line, the first radiator is provided with a first gap, and the second radiator is provided with a second gap; by setting the positions of the first feeding point and the second feeding point and controlling the phase difference of the electric signal reaching the first feeding point and the second feeding point, an antenna with high efficiency and low SAR value can be constructed. The embodiment of the present application provides an antenna and a foldable electronic device, and high efficiency and low SAR value of the antenna can be realized.

Description

Technical Field

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

[0002] With the continuous development of wireless communication technology, more and more electronic devices, such as mobile phones, headphones, tablets, wearable devices, and data cards, have appeared in people's daily lives. During normal communication, electronic devices generate electromagnetic radiation, and excessive electromagnetic radiation may affect human health. Therefore, various countries and regions generally have relatively strict regulations on the head specific absorption rate (SAR) and body specific absorption rate (SAR) of electronic devices. Antenna design for foldable electronic devices is very difficult because it needs to consider the antenna efficiency and SAR value in both the unfolded and folded states. Summary of the Invention

[0003] The embodiments of the present application provide an antenna and a foldable electronic device, which can achieve high efficiency and low SAR value of the antenna.

[0004] In one aspect, an embodiment of the present application provides an antenna for use in a foldable electronic device. The foldable electronic device includes a rotating shaft and a first body and a second body disposed on either side of the rotating shaft. The antenna includes a feed source, a first radiator, a second radiator, a first feeding point, a second feeding point, and a radio frequency connection line.

[0005] The first radiator is disposed in the first body, and the second radiator is disposed in the second body. One end of the first radiator close to the rotating shaft is grounded, and one end of the second radiator close to the rotating shaft is grounded. The first radiator is fed with an electrical signal through a first feeding point, and the second radiator is fed with an electrical signal through a second feeding point. The first feeding point and the second feeding point are connected by a radio frequency connecting line. A first slit is provided on the first radiator, and a second slit is provided on the second radiator.

[0006] The positions of the first feeding point and the second feeding point and the phases of the electrical signals at the first feeding point and the second feeding point are set to:

[0007] The first feeding point and the second feeding point are both arranged between the first gap and the second gap, and the phases of the electrical signals at the first feeding point and the second feeding point are inverted; or,

[0008] The first feeding point is arranged on a side of the first slot away from the second slot, the second feeding point is arranged on a side of the second slot away from the first slot, and the phases of the electrical signals at the first feeding point and the second feeding point are inverted; or,

[0009] The first feeding point is arranged between the first slot and the second slot, and the second feeding point is arranged on a side of the second slot away from the first slot, or the first feeding point is arranged on a side of the first slot away from the second slot, and the second feeding point is arranged between the first slot and the second slot, and the phases of the electrical signals at the first feeding point and the second feeding point are in phase.

[0010] An embodiment of the present application provides an antenna, which utilizes the space on the two main bodies of a foldable electronic device to respectively set radiators. The two radiators are connected by a radio frequency connection line to form a distributed antenna. By controlling the phase difference of the signals fed into the radiators on both sides by the feed source, a symmetrical distribution of current is achieved on at least some of the radiators on both sides of the rotating shaft in the unfolded state. In the folded state, the two radiators constitute adjacent parallel radiators, and the currents on at least some of the parallel radiators are distributed in the same direction, thereby achieving high efficiency and low SAR value of the antenna.

[0011] In a possible implementation, the antenna further includes a phase shifter connected between the first feeding point and the second feeding point.

[0012] By adding a device such as a phase shifter that can adjust the phase of the wave to the radio frequency connection line, the phase difference between the electrical signal reaching the first feeding point and the second feeding point can also be controlled.

[0013] In a possible implementation, the phase shifter is disposed in the first body or in the second body.

[0014] The phase shifter can be arranged in the first body or the second body to improve the flexibility of position arrangement.

[0015] In one possible embodiment, the first radiator and the second radiator are arranged axially symmetrically with respect to the rotation axis, and the first slot and the second slot are arranged axially symmetrically with respect to the rotation axis, thereby meeting antenna efficiency requirements while maintaining the overall appearance of the foldable electronic device.

[0016] When the first radiator and the second radiator are arranged axially symmetrically with respect to the rotating axis, it is beneficial to construct a common mode mode of the linear antenna centered on the rotating axis when the electronic device is in an unfolded state, and when the electronic device is in a folded state, the adjacent currents and the currents in the thickness direction of the electronic device are distributed in the same direction, so as to improve the efficiency of the antenna and reduce the SAR value of the antenna.

[0017] In a possible embodiment, a third slot is further provided on the first radiator, and a fourth slot is further provided on the second radiator. The third slot is located on the side of the first slot facing away from the second radiator, and the fourth slot is located on the side of the second slot facing away from the first radiator. The first feeding point and the second feeding point are both provided between the third slot and the fourth slot.

[0018] The first radiator and the second radiator located between the third slot and the fourth slot constitute the radiator of the antenna provided in the embodiment of the present application, so as to limit the length of the antenna radiator.

[0019] In a possible implementation, the radio frequency connection line includes a cable or a flexible circuit board.

[0020] The length of radio frequency connecting lines such as cables and flexible circuit boards can be controlled to control the phase difference between the electrical signal reaching the first feeding point and the second feeding point.

[0021] In one possible embodiment, when the foldable electronic device is in an unfolded state, the extension direction of the first radiator and the second radiator is perpendicular to the extension direction of the rotating shaft, and the distance between the first radiator and the second radiator is less than the width of the rotating shaft; when the foldable electronic device is in a folded state, the extension directions of the first radiator and the second radiator are consistent, and the first radiator and the second radiator overlap in the thickness direction of the foldable electronic device.

[0022] When the electronic device is in the unfolded state, the first radiator and the second radiator are axially symmetrically distributed relative to the rotating axis, and the distance between the first radiator and the second radiator is smaller than the width of the rotating axis. This is not only conducive to constructing a common mode mode of the wire antenna centered on the rotating axis, but also can reasonably utilize the space of the electronic device to arrange the antenna.

[0023] In a possible implementation, when the foldable electronic device is in an unfolded state, the currents on the first radiator and the second radiator are distributed in opposite directions; when the foldable electronic device is in a folded state, the currents on the first radiator and the second radiator are distributed in the same direction.

[0024] In the unfolded state, the above current distribution can form a common mode mode of the wire antenna to improve the efficiency of the antenna and reduce the SAR value. In the folded state, the interference of the current distributed in the same direction is small, which can ensure the high efficiency and low SAR value of the antenna.

[0025] In a possible implementation manner, the first radiator is electrically connected to the rotating shaft and is grounded through the rotating shaft, and the second radiator is electrically connected to the rotating shaft and is grounded through the rotating shaft.

[0026] The first radiator and the second radiator are grounded via the rotating shaft, which can simplify the grounding structure of the antenna and improve the compactness of the spatial arrangement of the antenna.

[0027] In a possible implementation, there is a gap between the first radiator and the floor, and a groove is formed between the first radiator and the floor to form an electrical connection. There is a gap between the second radiator and the floor, and a groove is formed between the second radiator and the floor to form an electrical connection.

[0028] When an electrical signal is fed into the first radiator, the first radiator and the ground can be regarded as forming a slot antenna; when an electrical signal is fed into the second radiator, the second radiator and the ground can be regarded as forming a slot antenna.

[0029] In a possible implementation, a tuning switch is provided on the first radiator, and two tuning switches are respectively provided on both sides of the first slot; a tuning switch is provided on the second radiator, and two tuning switches are respectively provided on both sides of the second slot.

[0030] The tuning switch may be configured to adjust the resonant frequencies of the first resonance and the second resonance of the first radiator and the second radiator, respectively.

[0031] Another aspect of an embodiment of the present application provides a foldable electronic device, including a hinge, a first body and a second body arranged on both sides of the hinge, and the antenna provided in the above embodiment.

[0032] The foldable electronic device provided in the embodiment of the present application forms a distributed antenna by arranging radiators on both sides of a rotating shaft, connecting the radiators on both sides through a radio frequency connecting line, and controlling the phase difference of the electrical signal reaching the radiators on both sides, so that when the foldable electronic device is in the unfolded state, a common mode mode of the linear antenna can be formed. When the electronic device is in the folded state, since the current directions of at least some of the adjacent parallel radiating branches on the first body and the second body are basically the same, the foldable electronic device can achieve high efficiency and low SAR value in both the unfolded state and the folded state.

[0033] In a possible implementation, the electronic device includes a metal frame, and the metal frames located on both sides of the rotating shaft respectively form a first radiator and a second radiator.

[0034] The metal frames on both sides of the rotating shaft are used as the radiators of the antenna, so that the structure of the antenna is simple and easy to implement.

[0035] In a possible implementation, a portion of the length of a top frame located at the top of the electronic device or a portion of the length of a bottom frame located at the bottom of the electronic device forms the first radiator and the second radiator.

[0036] Using the top or bottom frame of an electronic device as the radiator of the antenna is conducive to the realization of an axisymmetric structure, so that the foldable electronic device can achieve high efficiency and low SAR value in both the unfolded state and the folded state.

[0037] In another aspect, the present application provides an antenna including a feed, a first radiator, a second radiator, and a third radiator, wherein the first radiator, the second radiator, and the third radiator extend on the same straight line, the third radiator is located between the first radiator and the second radiator, and the length of the third radiator is shorter than the lengths of the first radiator and the second radiator.

[0038] The first radiator is fed with an electrical signal through a first feeding point, the second radiator is fed with an electrical signal through a second feeding point, the first feeding point and the second feeding point are connected by a radio frequency connecting line, the third radiator is grounded, and the phases of the electrical signals reaching the first feeding point and the second feeding point are the same.

[0039] In the antenna provided in the embodiment of the present application, the first radiator and the second radiator are arranged on both sides of the third radiator, and the phase difference of the electrical signal reaching the first radiator and the second radiator is controlled to be in the same phase, which can form a common mode of the linear antenna and achieve the effects of high efficiency, wide bandwidth and low SAR value.

[0040] In a possible embodiment, the first radiator and the second radiator are arranged axially symmetrically with respect to the third radiator, and the positions of the first feeding point and the second feeding point are arranged axially symmetrically with respect to the third radiator; the grounding point of the first radiator is located on the side of the first feeding point facing the third radiator, and the grounding point of the second radiator is located on the side of the second feeding point facing the third radiator.

[0041] The first radiator and the second radiator are arranged axially symmetrically with respect to the third radiator to construct a common mode mode of the linear antenna centered on the third radiator, which can reduce the SAR value of the antenna.

[0042] In a possible implementation, the third radiator is connected to a tuning inductor, and the efficiency of the resonance generated by the third radiator is lower than the efficiency of the resonance generated by the first radiator and the second radiator.

[0043] By setting a tuning inductor to reduce the efficiency of the resonance generated by the third radiator, the third radiator can be prevented from affecting the resonance of the first radiator and the second radiator, thereby avoiding affecting the common mode mode of the structural wire antenna.

[0044] On the other hand, an embodiment of the present application further provides an antenna, including a feed source and a first radiator and a second radiator extending on the same straight line, the first radiator is fed with an electrical signal through a first feeding point, and the second radiator is fed with an electrical signal through a second feeding point, the first radiator and the second radiator are the same length and are arranged left and right, the position of the first feeding point on the first radiator is the same as the position of the second feeding point on the second radiator, the first feeding point and the second feeding point are connected by a radio frequency connecting line, and the phases of the electrical signals reaching the first feeding point and the second feeding point are reversed.

[0045] The antenna provided in the embodiment of the present application has the same structure as the first radiator and the second radiator, which are arranged in a left-right arrangement. The phase difference between the electrical signals reaching the first radiator and the second radiator is controlled to be in opposite phases, which can form a common mode of the linear antenna and achieve high efficiency, wide bandwidth, and low SAR value.

[0046] In a possible implementation, the grounding point of the first radiator is located on a side of the first feeding point facing the second radiator, and the grounding point of the second radiator is located on a side of the second feeding point facing away from the first radiator.

[0047] The grounding points on the first radiator and the second radiator are both arranged on the same side of their respective feeding points, so that the first radiator and the second radiator have the same structure and are arranged in a left-right arrangement.

[0048] Another aspect of the present application embodiment further provides an electronic device, comprising the antenna provided in the above embodiment.

[0049] The electronic device provided in the embodiment of the present application realizes the common mode of the linear antenna by constructing a symmetrical radiator structure on a non-foldable electronic device and controlling the phase difference of the electrical signal reaching the two radiators, thereby achieving high efficiency and low SAR value of the antenna.

[0050] The antenna and foldable electronic device provided in the embodiments of the present application utilize the space on the two main bodies of the foldable electronic device to respectively set up radiators. The two radiators are connected by a radio frequency connection line to form a distributed antenna. By controlling the phase difference of the signal fed into the radiators on both sides by the feed source, the current is distributed in opposite directions on the radiators on both sides of the rotating shaft in the unfolded state, thereby constructing the common mode mode of the outgoing antenna. In the folded state, the two radiators constitute adjacent parallel radiators, and the current on the parallel radiators is distributed in the same direction, thereby achieving high efficiency and low SAR value of the antenna. In addition, compared with setting up antennas on each of the two main bodies of the foldable electronic device, the distributed antenna provided in the embodiments of the present application can obtain more resonant modes and bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1a A schematic diagram of the common mode of the slot antenna provided in one embodiment of the present application;

[0052] Figure 1b A schematic diagram of the differential mode of a slot antenna provided in one embodiment of the present application;

[0053] Figure 1c A schematic diagram of the common mode of a wire antenna provided in one embodiment of the present application;

[0054] Figure 1d A schematic diagram of a differential mode of a wire antenna provided in one embodiment of the present application;

[0055] Figure 2 A schematic structural diagram of a foldable electronic device in an unfolded state and a folded state provided by an embodiment of the present application;

[0056] Figure 3 A schematic structural diagram of an antenna provided in one embodiment of the present application;

[0057] Figure 4a A schematic structural diagram of an antenna provided in one embodiment of the present application;

[0058] Figure 4b A schematic structural diagram of another antenna provided in one embodiment of the present application;

[0059] Figure 4c A schematic structural diagram of another antenna provided in one embodiment of the present application;

[0060] Figure 5 A schematic structural diagram of an antenna provided in one embodiment of the present application;

[0061] Figure 6 A graph showing return loss coefficients of the first antenna and the second antenna according to an embodiment of the present application;

[0062] Figure 7 This is an efficiency curve diagram of the first antenna and the second antenna provided in one embodiment of the present application;

[0063] Figures 8a-8d This is a schematic heat map of the first antenna;

[0064] Figures 9a-9d is a schematic heat map of the second antenna;

[0065] Figures 10a-10f is a schematic heat map of the antenna at the first resonant frequency at different phases;

[0066] Figures 11a-11f is a schematic heat map of the antenna at the second resonant frequency at different phases;

[0067] Figure 12a-12f is the current distribution diagram of the antenna under different phases;

[0068] Figure 13 A comparison of the current distribution of the antenna in the unfolded and folded states;

[0069] Figure 14 A comparison diagram of the radiation efficiency of antennas of electronic devices in a folded state;

[0070] Figure 15 A comparison diagram of the system efficiency of antennas of electronic devices in a folded state;

[0071] Figure 16 Another structural schematic diagram of an antenna provided in one embodiment of the present application;

[0072] Figure 17 is a graph of return loss coefficients of the first antenna and the second antenna;

[0073] Figure 18is an efficiency curve diagram of the first antenna and the second antenna;

[0074] Figure 19a-Figure 19d is a schematic heat map of the second antenna;

[0075] Figure 20a-20f is a schematic heat map of the antenna at the first resonant frequency at different phases;

[0076] Figure 21a-Figure 21f is a schematic heat map of the antenna at the second resonant frequency at different phases;

[0077] Figure 22a-22f is the current distribution diagram of the antenna under different phases;

[0078] Figure 23 A schematic diagram of another structure of an antenna provided in an embodiment of the present application;

[0079] Figure 24 is a graph of return loss coefficients of the first antenna and the second antenna;

[0080] Figure 25 is an efficiency curve diagram of the first antenna and the second antenna;

[0081] Figure 26a-26d This is a schematic heat map of the first antenna;

[0082] Figure 27a-Figure 27f is a schematic heat map of the antenna at the first resonant frequency at different phases;

[0083] Figure 28a-28f is a schematic heat map of the antenna at the second resonant frequency at different phases;

[0084] Figure 29a-29f is the current distribution diagram of the antenna under different phases;

[0085] Figure 30 A schematic structural diagram of a wire antenna provided in one embodiment of the present application;

[0086] Figure 31 for Figure 30 Provide the return loss coefficient curve corresponding to the antenna;

[0087] Figure 32 for Figure 30 Provide an efficiency graph of the antenna;

[0088] Figure 33a-Figure 33b for Figure 30 The current distribution diagram of the provided antenna;

[0089] Figure 34a-Figure 34d This is a schematic heat map of the first antenna;

[0090] Figure 35 A schematic structural diagram of an antenna provided in one embodiment of the present application;

[0091] Figure 36 for Figure 35 Provides a graph of the antenna's radiation efficiency at different phases;

[0092] Figure 37 for Figure 35 Provides system efficiency curves of antennas at different phases;

[0093] Figure 38a-Figure 38b is the current distribution diagram of the antenna under the same phase;

[0094] Figure 39a-39d is a schematic heat map of the antenna under the same phase;

[0095] Figure 40 A simplified structural diagram of an antenna provided in one embodiment of the present application;

[0096] Figure 41 A schematic structural diagram of another antenna provided in one embodiment of the present application;

[0097] Figure 42 for Figure 41 Provides a graph of the antenna's radiation efficiency at different phases;

[0098] Figure 43 for Figure 41 Provides system efficiency curves of antennas at different phases;

[0099] Figure 44a-Figure 44b is the current distribution diagram of the antenna under the same phase;

[0100] Figure 45a-45d is a schematic heat map of the antenna under the same phase;

[0101] Figure 46a-Figure 46b is the current distribution diagram of the antenna under reverse phase;

[0102] Figure 47a-47d is a schematic heat map of the antenna under reverse phase;

[0103] Figure 48 A simplified structural diagram of an antenna provided in one embodiment of the present application;

[0104] Figure 49 A schematic structural diagram of another antenna applied to a foldable electronic device provided in one embodiment of the present application.

[0105] Description of reference numerals:

[0106] 100-electronic device; 11a-first body; 11b-second body; 12-rotating shaft; 13-floor; 21-first radiator; 211-first gap; 212-third gap; 22-second radiator; 221-second gap; 222-fourth gap; 23-feed source; 24-RF connecting line; 25-third radiator; F1-first feeding point; F2-second feeding point; SW1, SW2, SW3, SW4-tuning switches; 31-circuit board; 32-radiator; 33-feed source; 34-feed line. DETAILED DESCRIPTION

[0107] The following explains the professional terms mentioned in the embodiments of the present application to facilitate understanding by those skilled in the art.

[0108] Antenna return loss: This can be understood as the ratio of the signal power reflected back to the antenna port by the antenna circuit to the antenna port's transmit power. A smaller reflected signal indicates a larger signal radiated from the antenna into space, and the antenna's radiation efficiency is higher. A larger reflected signal indicates a smaller signal radiated from the antenna into space, and the antenna's radiation efficiency is lower. Antenna return loss can be expressed using the S11 parameter, which is typically a negative number. A smaller S11 parameter indicates a lower antenna return loss and a higher antenna system efficiency. A larger S11 parameter indicates a greater antenna return loss and a lower antenna system efficiency.

[0109] Antenna isolation refers to the ratio of the signal received by one antenna to the signal from the transmitting antenna. Isolation is a physical quantity used to measure the degree of antenna mutual coupling. Assuming two antennas form a two-port network, the isolation between the two antennas is the S21 and S12 values ​​between the antennas. Antenna isolation can be expressed using the S21 and S12 parameters. These parameters are typically negative numbers. Smaller S21 and S12 values ​​indicate greater isolation and less mutual coupling between the antennas. Larger S21 and S12 values ​​indicate less isolation and greater mutual coupling between the antennas. Antenna isolation depends on factors such as the antenna radiation pattern, the spatial distance between the antennas, and the antenna gain. When the antenna isolation is less than -13dB, it is considered to be well isolated.

[0110] Antenna system efficiency: refers to the ratio of the power radiated into space by the antenna (that is, the power of the electromagnetic wave part that is effectively converted) to the input power of the antenna.

[0111] Antenna radiation efficiency: This refers to the ratio of the power radiated into space by the antenna (i.e., the power effectively converted into electromagnetic waves) to the active power input to the antenna. Active power input to the antenna = antenna input power - power loss. Power loss mainly includes return loss and metal ohmic loss and / or dielectric loss.

[0112] Common Mode (CM) of slot antenna (also known as slot antenna):

[0113] Figure 1a This is a common mode diagram of the slot antenna provided in one embodiment of the present application. Figure 1a As shown, the slot antenna can be formed by providing a hollow slot or gap on the radiator, or it can be formed by the radiator and the ground (such as the floor / circuit board 31) enclosing a slot or gap, for example, the structure of the radiator and the ground constructs the slot or gap, and / or the radiator and the ground are electrically connected to form the slot or gap, or, for example, the slot or gap can be formed by grooving on the floor. In one embodiment, an opening is provided on one side of the gap, i.e., the radiator 32, and the opening is connected to the feed source 33. In another embodiment, the feed source 33 can also be connected within a preset length range from the opening. Anti-symmetrical feed can be used at or near the opening of the radiator 32. Anti-symmetrical feed can be understood as the positive and negative poles of the feed unit 33 are respectively connected to the two ends of the opening, and the signals output by the positive and negative poles of the feed unit 33 have the same amplitude and opposite phases, for example, the phase difference is 180°±10°. At this time, the current is asymmetrically distributed on the radiators on both sides of the opening, for example Figure 1a It should be understood that the "unidirectional distribution" of current mentioned in this application does not mean that the current is directed in a pure, single, identical direction. Instead, it schematically indicates that the current is generally directed in the same direction on one or more radiators, for example, the current flows from one side of the radiator to the other. A slot antenna pattern based on the asymmetric distribution of current on the radiators on both sides of the opening, or the unidirectional distribution of current on the conductor surrounding the slot, can be referred to as a slot antenna CM mode.

[0114] Differential Mode (DM) of slot antenna:

[0115] Figure 1bSchematic diagram of the differential mode of the slot antenna provided in one embodiment of the present application. In one embodiment, the feed source 33 is connected to the middle position of the slot, and the middle position of the radiator 32 can adopt symmetrical feed. Symmetrical feed can be understood as one end of the feed unit 33 being connected to the radiator and the other end being grounded, wherein the connection point (feeding point) between the feed unit 33 and the radiator is located in the middle position of the radiator. The "middle position" of the radiator mentioned in this application includes the center of the radiator, for example, it can be the midpoint of the geometric structure, or the midpoint of the electrical length (or the area within a certain range near the above midpoint). In one embodiment, the connection between the feed unit 33 and the radiator covers the center of the radiator. At this time, on the conductor around the slot, the current is distributed around the slot, and is symmetrically distributed on both sides of the middle position of the slot, for example, the current on both sides of the radiator 32 in the figure is distributed in opposite directions. It should be understood that the "reversely distributed" current mentioned in this application does not mean that the current is directed in a purely, single, opposite direction. Instead, it schematically indicates that the current flows in substantially opposite directions along one or more radiator segments, for example, from one point on the radiator to opposite sides of the radiator. A slot antenna pattern characterized by symmetrical current distribution on both sides of the connection between the feed source 33 and the radiator 32, or by symmetrical current distribution around the slot, can be referred to as a DM mode of the slot antenna.

[0116] It should be understood that the radiator of the slot antenna can be understood as a metal structure that generates radiation (for example, a part of the floor), which may include an opening, such as Figure 1a Alternatively, it can be a complete ring, such as Figure 1b As shown, it can be adjusted according to actual design or production needs. For example, for the CM mode of the slot antenna, it can also be Figure 1b As shown, a complete annular radiator is used. For example, two feeding points are set in the middle position of the radiator on one side of the slot and an anti-symmetric feeding method is adopted (for example, signals with the same amplitude and opposite phases are fed into the two ends of the original opening position respectively). The same effect as Figure 1a The antenna structure shown in the figure has a similar effect. Correspondingly, for the DM mode of the slot antenna, it can also be Figure 1a As shown, a radiator including an opening is used. For example, a symmetrical feeding method is used at both ends of the opening (for example, the same feed source signal is fed into both ends of the radiator on both sides of the opening), and the same effect as Figure 1b The antenna structure shown has a similar effect.

[0117] It should be understood that in actual applications, the position of the feeding point of the slot antenna is not restricted and needs to be designed according to the actual working frequency band requirements. Figure 1a and Figure 1bThe feed point position is for illustration only. A slot antenna may experience both CM and DM mode resonances. Adjusting the feed point position can affect the characteristics of both resonances.

[0118] It's important to note that the slot antenna's pattern can also be defined based on the distribution of the electric field. In a slot antenna, the electric field is distributed within the slot, pointing from one side of the slot to the other. The electric field at the center of the slot is distributed in opposite directions, forming the slot antenna's CM mode. The electric field at the center of the slot is distributed in the same direction on both sides, forming the slot antenna's DM mode.

[0119] Common mode of wire antenna: Figure 1c This is a schematic diagram of the common mode of the wire antenna provided in one embodiment of the present application. Figure 1c As shown, in one embodiment, the radiator 32 of the wire antenna is connected to the feed source 33 via a feed line 34. The connection between the feed line 34 and the radiator 32 can be located in the middle of the radiator 32. The current on the radiator 32 is symmetrically distributed on both sides of the middle position, such as the reverse distribution shown in the figure. The wire antenna mode based on the symmetrical current distribution on both sides of the connection between the radiator 32 and the feed line 34 can be called the CM mode of the wire antenna.

[0120] Differential mode of wire antenna: Figure 1d This is a schematic diagram of the differential mode of a wire antenna provided in one embodiment of the present application. Figure 1d As shown, the radiator 32 of the wire antenna is connected to the feed source 33 via a feed line 34. The connection between the feed line 34 and the radiator 32 can be located in the middle of the radiator 32. The current on the radiator 32 is asymmetrically distributed on either side of the middle, such as the unidirectional distribution shown in the figure. The wire antenna mode characterized by the asymmetrical current distribution on either side of the connection between the radiator 32 and the feed line 34 can be referred to as the DM mode of the wire antenna.

[0121] It should be understood that the radiator 32 of the wire antenna can be understood as a metal structure that generates radiation, with both ends being open. The position of the feeding point on the radiator 32 is not limited, and the feeding point can be as follows: Figure 1c and Figure 1d The feed point can be set in the middle position of the radiator 32, or in an area close to the middle position or other positions. The position of the feed point needs to be designed according to the actual working frequency band requirements. The number of radiators 32 of the wire antenna can be one, such as Figure 1c As shown, or, it can be two pieces, such as Figure 1d As shown, it can be adjusted according to actual design or production needs. For example, for the CM mode of the wire antenna, it can also be Figure 1dAs shown, two radiators are used, and the two ends of the two radiators are arranged opposite to each other with a gap between them, which can also be obtained. Figure 1c The antenna structure shown in the figure has a similar effect. Correspondingly, for the DM mode of the wire antenna, it can also be Figure 1c As shown in the figure, a radiator is used. For example, two feeding points are set in the middle position of the radiator and an antisymmetric feeding method is adopted (for example, two symmetrical feeding points on the radiator are fed with signals with the same amplitude and opposite phases respectively), and the same effect as Figure 1d For example, the wire antenna may also include a T-shaped wire antenna, which refers to a wire antenna with a constant ground point on the radiator. The constant ground point is equivalent to incorporating an inductor, that is, the structure does not necessarily need to be grounded, and the same effect can be achieved by incorporating an inductor.

[0122] It should be noted that, in actual applications, a wire antenna may generate CM mode resonance and DM mode resonance at the same time. Adjusting the position of the feeding point can affect the characteristics of the two resonances.

[0123] As people's living standards continue to improve, the screen display effects of electronic devices such as mobile phones are becoming increasingly important. In order to achieve a larger screen area on a smaller electronic device, the electronic device can adopt a foldable structure. A foldable electronic device can have two main bodies, which can rotate relative to each other around a rotation axis and fold so that the foldable electronic device has two states: unfolded and folded. The antenna design of a foldable electronic device is relatively difficult. On the one hand, in the folded state, foldable electronic devices lack a usable side compared to conventional electronic devices, that is, the space for antenna arrangement is limited; on the other hand, switching between the unfolded state and the folded state will cause the state of the antenna to change, resulting in a significant change in antenna performance. For example, the antenna performance will decrease when switching from the unfolded state to the folded state.

[0124] In a related technology, a main radiator and a backup parasitic branch can be provided on each of the two main bodies of a foldable electronic device. When the foldable electronic device is unfolded, the backup parasitic branch is positioned away from the main radiator, allowing the main radiator to function as an antenna. When the foldable electronic device is folded, the main radiator and the backup parasitic branch are positioned close together, and the two realize the antenna function through coupled radiation. This design does not effectively utilize the space of the unfolded foldable electronic device, and the antenna performance in the unfolded state may be reduced.

[0125] In another related technology, a main radiator and a secondary radiator can be respectively provided on the two main bodies of a foldable electronic device, and the main radiator and the secondary radiator are connected by a radio frequency connection line. When the foldable electronic device is in the unfolded state, the radio frequency connection line connects the main radiator and the secondary radiator so that they radiate together to realize the antenna function. When the foldable electronic device is in the folded state, the main radiator and the secondary radiator are close to each other, and the radio frequency connection line can be disconnected so that the secondary radiator acts as a coupled parasitic of the main radiator and radiates together with the main radiator to realize the antenna function. This design makes good use of space when the foldable electronic device is in the unfolded state, but coupling feeding in the folded state may cause the efficiency of the antenna to decrease and / or cause the specific absorption rate (SAR) value to increase.

[0126] It should be noted that the SAR value of an antenna is a regulatory requirement. Organizations such as the European Conformity (CE) and the Federal Communications Commission (FCC) have strict regulations on the SAR value of antennas for electronic devices. These SAR value regulations directly affect the wireless performance of users when using electronic devices. Some antenna types have relatively high SAR values. In actual use, to avoid exceeding the specified value, the device has power backoff, which can lead to a decrease in wireless performance and directly affect the user's actual experience. Therefore, how to optimize the antenna design to achieve higher antenna performance while obtaining a lower SAR value and reducing power backoff, given the limited size and space of the radiator structure of an electronic device, is a top priority in the antenna design of current electronic devices.

[0127] Based on the above problems, an embodiment of the present application provides an antenna and a foldable electronic device, in which radiators are respectively set up using the space on the two main bodies of the foldable electronic device. The two radiators are connected by a radio frequency connecting line to form a distributed antenna. By controlling the phase difference of the signals fed into the radiators on both sides by the feed source, the current is symmetrically distributed on the radiators on both sides of the rotating shaft in the unfolded state. In the folded state, the two radiators constitute adjacent parallel radiators, and the currents on the parallel radiators are distributed in the same direction, thereby achieving high efficiency and low SAR value of the antenna.

[0128] Example 1

[0129] The present application provides a foldable electronic device, including but not limited to a mobile phone, tablet computer, laptop computer, monitor, vehicle-mounted device, or other terminal device with a display screen. The present application does not impose any specific restrictions on the specific form of the foldable electronic device. The foldable electronic device can be folded once, twice, or more times. For ease of understanding, the present application uses a foldable mobile phone that is folded once to specifically describe the specific structure of the foldable electronic device.

[0130] Figure 2 This is a schematic diagram of the structure of a foldable electronic device in an unfolded state and a folded state provided by an embodiment of the present application. Figure 2 As shown, the foldable electronic device 100 includes a first body 11a and a second body 11b, which can rotate around a rotation axis 12 therebetween, so that the ends of the first body 11a and the second body 11b away from the rotation axis 12 are relatively close to or relatively far away from each other.

[0131] In the embodiment of the present application, the side of the electronic device 100 with the flexible screen can be defined as the front side, and the other side opposite to the flexible screen can be defined as the back side. The foldable electronic device 100 can adopt an inward folding structure, that is, the electronic device 100 is folded toward the side with the flexible screen, and at least one of the first body 11a and the second body 11b is rotated according to the arrow in the figure. After folding, the flexible screen is located inside the electronic device 100. It is not difficult to understand that the foldable electronic device 100 can also adopt an outward folding structure, that is, the electronic device 100 is folded toward the back side, and the flexible screen is located outside the electronic device 100 after folding.

[0132] The first body 11a and the second body 11b may be implemented in the form of a middle frame, a rear shell, a middle plate, and other structures of the electronic device 100. The first body 11a and the second body 11b may be made of metal, plastic, ceramic, glass, and other structures, which have high structural strength and are used to support the flexible screen. The first body 11a and the second body 11b may also be connected to structures such as a motherboard, a battery, and a camera module. For ease of explanation, in the embodiment of the present application, the motherboard is set in the first body 11a, the first body 11a on the left side is used as the main screen, and the second body 11b on the right side is used as the secondary screen.

[0133] In addition, for ease of explanation, taking the electronic device 100 in the unfolded state as an example, when the user is viewing the display surface, the hinge 12 is located in the middle of the left main screen and the right secondary screen. The upper and lower sides of the display surface can be defined as the top and bottom of the electronic device 100, respectively. The four frames located at the upper, lower, left, and right sides of the display surface can be positioned as the top frame, bottom frame, left frame, and right frame, respectively. It is not difficult to understand that the hinge 12 is arranged parallel to the left and right frames, and perpendicular to the top and bottom frames. The top frame can include two sections located on the left and right sides of the hinge 12, and the bottom frame can include two ends located on both sides of the hinge 12.

[0134] The antenna provided in this application is described in detail below with reference to the accompanying drawings and specific embodiments.

[0135] Figure 3 The schematic diagram of the structure of the antenna provided in one embodiment of the present application can be regarded as a schematic diagram of the partial structure of the bottom of the electronic device 100 in FIG1 . Figure 3 As shown, the antenna provided in the embodiment of the present application may include a feed source 23, a radio frequency connection line 24, a first radiator 21 disposed in the first body 11a, and a second radiator 22 disposed in the second body 11b.

[0136] The feed source 23 is used to feed power to the first radiator 21 and the second radiator 22. The location of the feed source 23 is not specifically limited. For example, it can be set in the first body 11a or the second body 11b. In the embodiment of the present application, the feed source 23 can be set in the first body 11a and electrically connected to the main board of the first body 11a.

[0137] This application does not limit the manufacturing process of the first radiator 21 and the second radiator 22. For example, the first radiator 21 and the second radiator 22 can be made from the metal frame of an electronic device, a flexible printed circuit (FPC), laser processing, or spray coating. For ease of illustration, the figures of the embodiments of this application illustrate that the first radiator 21 and the second radiator 22 are made from the metal frame of the electronic device 100.

[0138] The lengths and specific locations of the first radiator 21 and the second radiator 22 are not specifically limited in the embodiments of the present application. The first radiator 21 and the second radiator 22 can be disposed on the bottom frame or the top frame of the electronic device 100. The first radiator 21 can extend to the left frame, and the second radiator 22 can extend to the right frame. For ease of explanation, the following figures take the first radiator 21 and the second radiator 22 disposed on the bottom frame of the electronic device 100 as an example.

[0139] It should be understood that the mainboard of the electronic device 100 is provided with a grounding area, and the middle frame, middle plate, and hinge 12 of the electronic device 100 are all grounded. In one possible embodiment, both ends of the first radiator 21 and both ends of the second radiator 22 can be grounded via the floor 13. In another possible embodiment, the first radiator 21, the second radiator 22, and the hinge 12 overlap at least partially in the direction of the bottom frame. The end of the first radiator 21 near the hinge 12 can be grounded via the hinge 12, while the other end can be grounded via the floor 13. The end of the second radiator 22 near the hinge 12 can be grounded via the hinge 12, while the other end can be grounded via the floor 13. Using the hinge 12 to ground the first and second radiators 21, 22 can improve the compactness of the structure and increase space utilization. In one possible embodiment, the width of the hinge 12 can be between 20 mm and 50 mm, for example, less than 30 mm, and the distance between the first and second radiators 21, 22 can be less than 30 mm.

[0140] It should be understood that there is a gap between the first radiator 21 and the floor 13, and both ends of the first radiator 21 are grounded, that is, the first radiator 21 and the ground are electrically connected to form a slot. When an electrical signal is fed to the first radiator 21, the first radiator 21 and the ground can be considered to form a slot antenna. Similarly, there is a gap between the second radiator 22 and the floor 13, and both ends of the second radiator 22 are grounded, that is, the second radiator 22 and the ground are electrically connected to form a slot. When an electrical signal is fed to the second radiator 22, the second radiator 22 and the ground can be considered to form a slot antenna. This embodiment of the present application does not specifically limit the width of the gap between the first radiator 21 and the floor 13, and between the second radiator 22 and the floor 13. By way of example, the gap width can be less than 2 mm.

[0141] A first slot 211 can be provided on the first radiator 21, and a second slot 221 can be provided on the second radiator 22. The first slot 211 and the second slot 221 can be formed by providing a slit in a metal frame and filling the slit with an insulating plastic material. When an electrical signal is fed to the first radiator 21 having the first slot 211, the two radiator segments separated by the first slot 211 can serve as a main feed branch and a coupled parasitic branch, respectively, forming the CM mode and the DM mode of the slot antenna, respectively. The same applies to the second radiator 22, and will not be further described.

[0142] In the embodiment of the present application, the first radiator 21 can receive the electrical signal input by the feed source 23 through the first feeding point F1, and the second radiator 22 can receive the electrical signal input by the feed source 23 through the second feeding point F2. The first feeding point F1 and the second feeding point F2 can be connected by the RF connection line 24, so that the first radiator 21 and the second radiator 22 constitute a distributed antenna. When the foldable electronic device 100 switches between the unfolded state and the folded state, the first radiator 21 and the second radiator 22 are always connected by the RF connection line 24 and used as a whole antenna. At this time, the current distribution on the first radiator 21 and the second radiator 22 will be affected by the signal phase difference when the electrical signal reaches the first feeding point F1 and the second feeding point F2, and cannot be regarded as a slot antenna alone. The first feeding point F1 can be positioned on the left or right side of the first slot 211, as indicated by the dotted-line circled area on the first radiator 21. The second feeding point F2 can be positioned on the left or right side of the second slot 221, as indicated by the dotted-line circled area on the second radiator 22. It is readily apparent that there are four basic combinations of designing the positions of the first and second feeding points F1 and F2 based on the left and right sides of the slot 221, thereby forming at least three different antenna structures.

[0143] Figure 4a This is a schematic diagram of the structure of an antenna provided in one embodiment of the present application. Figure 4a As shown, in the first form, the first feeding point F1 can be set on the side of the first slot 211 facing the second slot 221, that is, on the right side of the first slot 211, and the second feeding point F2 can be set on the side of the second slot 221 facing the first slot 211, that is, on the left side of the second slot 221. When the electronic device 100 is in the unfolded state, the radiator connected to the first feeding point F1 and located between the first slot 211 and the rotating shaft 12 constitutes a main feeding branch, and the radiator on the other side of the first slot 211 constitutes a coupled parasitic branch; the radiator connected to the second feeding point F2 and located between the second slot 221 and the rotating shaft 12 constitutes a main feeding branch, and the radiator on the other side of the second slot 221 constitutes a coupled parasitic branch. The end opening direction of the main feeding branch of the first radiator 21 is to the left, and the end opening direction of the main feeding branch of the second radiator 22 is to the right, and the end opening directions of the two main feeding branches are opposite.

[0144] Figure 4b This is a schematic diagram of the structure of another antenna provided in one embodiment of the present application. Figure 4bAs shown, in the second form, the first feeding point F1 can be set on the side of the first slot 211 away from the second slot 221, that is, on the left side of the first slot 211, and the second feeding point F2 can be set on the side of the second slot 221 facing the first slot 211, that is, on the left side of the second slot 221. In this case, the end opening direction of the main feeding branch of the first radiator 21 is rightward, and the end opening direction of the main feeding branch of the second radiator 22 is rightward, and the end opening direction of the two main feeding branches is the same.

[0145] In the third form, the first feeding point F1 can be set on the side of the first slot 211 facing the second slot 221, that is, on the right side of the first slot 211, and the second feeding point F2 can be set on the side of the second slot 221 facing away from the first slot 211, that is, on the right side of the second slot 221. At this time, the end opening direction of the main feeding branch of the first radiator 21 is to the left, and the end opening direction of the main feeding branch of the second radiator 22 is to the left, and the end opening directions of the two main feeding branches are the same. It is not difficult to understand that the antenna structure in the third form and the antenna structure in the second form can be regarded as the same, so the embodiments of the present application hereinafter only take the antenna structure in the second form as an example for specific description.

[0146] Figure 4c This is a schematic diagram of the structure of another antenna provided in one embodiment of the present application. The first feeding point F1 can be set on the side of the first slot 211 away from the second slot 221, that is, on the left side of the first slot 211, and the second feeding point F2 can be set on the side of the second slot 221 away from the first slot 211, that is, on the right side of the second slot 221. The end opening direction of the main feeding branch of the first radiator 21 is rightward, and the end opening direction of the main feeding branch of the second radiator 22 is leftward, and the end opening directions of the two main feeding branches are opposite.

[0147] When the electronic device is in the unfolded state, the first radiator 21 and the second radiator 22 function as distributed antennas. When the electronic device is in the folded state, the first radiator 21 and the second radiator 22 are arranged parallel and close to each other. It is understood that after the electronic device is folded, the first body 11a and the second body 11b may not be completely aligned, and there may be a gap near the hinge 12. Therefore, after the electronic device is folded, the first radiator 21 and the second radiator 22 may be arranged at a small angle, rather than being strictly parallel. Furthermore, the first radiator 21 and the second radiator 22 may not completely overlap in the thickness direction of the electronic device, but may have a certain error. It should be understood that the term "parallel" in this application does not mean that the extension directions of the first radiator 21 and the second radiator 22 are strictly parallel to each other. Instead, it allows the first radiator 21 and the second radiator 22 to be at a small angle, for example, less than 5°, which can be considered substantially parallel.

[0148] The concept of the embodiments of the present application is to control the phase difference between the electrical signals reaching the first radiator 21 and the second radiator 22 so that when the electronic device is in the unfolded state, the current is symmetrically distributed on the radiators on both sides of the rotation axis. At the same time, when the electronic device is in the folded state, the current directions on the parallel first radiator 21 and second radiators 22 remain consistent, thereby achieving high efficiency and low SAR. It should be understood that the current directions on the first radiator 21 and the second radiator 22 remain consistent, which does not mean that the current directions are purely and solely the same, but rather schematically indicates that the current is basically in the same direction on the two radiators, for example, the current flows from one side of the radiator to the other.

[0149] Below, Figure 4a 、 Figure 4b 、 Figure 4c These three antenna structures are used as three scenarios, and combined with more specific embodiments, the principle and effect of reducing the SAR value of the antenna by controlling the phase difference between the electrical signal reaching the first radiator 21 and the second radiator 22 are specifically explained.

[0150] Scene 1

[0151] Figure 5 This is a schematic diagram of the structure of an antenna provided in one embodiment of the present application. Figure 5 As shown, in this embodiment of the present application, metal frames can be provided on either side of the rotating shaft 12 as the first radiator 21 and the second radiator 22, respectively. An insulating plastic dielectric is filled between the inner surface of the metal frame and the middle frame of the electronic device. In one embodiment, the dielectric has a relative permittivity of 3.0 and a loss tangent of 0.01.

[0152] A first slit 211 and a third slit 212 are provided on the metal frame located in the first body 11a. The metal frame between the third slit 212 and the rotating shaft 12 can be regarded as the first radiator 21, and the first slit 211 divides the first radiator 21 into two branches; a second slit 221 and a fourth slit 222 are provided on the metal frame located in the second body 11b. The metal frame between the fourth slit 222 and the rotating shaft 12 can be regarded as the second radiator 22, and the second slit 221 divides the second radiator 22 into two branches.

[0153] One end of the first radiator 21 close to the rotating shaft 12 is grounded through the rotating shaft 12, and one end of the second radiator 22 close to the rotating shaft 12 is grounded through the rotating shaft 12. The first feeding point F1 feeds the branch on the right side of the first slot 211, and the second feeding point F2 feeds the branch on the left side of the second slot 221, that is, the end opening direction of the main feeding branch of the first radiator 21 is to the left, and the end opening direction of the main feeding branch of the second radiator 22 is to the right, and the end opening directions of the two main feeding branches are opposite.

[0154] In a specific embodiment, when the electronic device is in the unfolded state, the width of the rotating shaft 12 can be set to 30 mm, and the widths of the first gap 211 , the third gap 213 , the second gap 221 , and the fourth gap 222 can be 1.5 mm.

[0155] In addition, tuning switches SW1 and SW3 can be respectively set on the main feed branch and coupled parasitic branch of the first radiator 21, and tuning switches SW2 and SW4 can be respectively set on the main feed branch and coupled parasitic branch of the second radiator 22 to adjust the resonant frequency. The specific structure and working principle of the tuning switch are not described in detail in the embodiments of this application.

[0156] When the electronic device is in the unfolded state, if the first radiator 21 and the second radiator 22 are not connected by an RF connection line, but an electrical signal is fed to the first radiator 21 alone, the first radiator 21 and the ground can constitute a first antenna, which is a slot antenna. Similarly, if an electrical signal is fed to the second radiator 22 alone, the second radiator 22 and the ground can constitute a second antenna, which is a slot antenna.

[0157] Figure 6 A graph of return loss coefficients of the first antenna and the second antenna provided in one embodiment of the present application, wherein S11 and S22 represent the return loss characteristics of the first antenna and the second antenna, respectively, and S12 represents the isolation between the first antenna and the second antenna. Figure 7 This is an efficiency curve diagram of the first antenna and the second antenna provided in an embodiment of the present application, where E1 and E2 represent the system efficiency of the first antenna and the second antenna respectively, and R1 and R2 represent the radiation efficiency of the first antenna and the second antenna respectively. Figure 6 and Figure 7 As shown, when the first and second antennas are fed with electrical signals, their performance is comparable, with both antennas generating two resonances. The two center resonant frequencies of the two antennas coincide, with the first resonant frequency at 1.83 GHz and the second at 2.61 GHz. Furthermore, the isolation between the first and second antennas is less than -13 dB, indicating good isolation between the first and second antennas.

[0158] By simulating the 5mm body SAR values ​​of the first and second antennas on the backside and bottom sides of the electronic device (averaged at 10g) and normalizing them according to the -5dB efficiency, the SAR values ​​of the first antenna are shown in Table 1, and the SAR values ​​of the second antenna are shown in Table 2. It should be noted that the simulation surface of the SAR value in this application is set according to the location of the radiator. If the radiator is set on the bottom frame of the electronic device, the back and bottom sides are simulated. If the radiator is set on the top frame of the electronic device, the back and top sides can be simulated.

[0159] Table 1

[0160]

[0161] Table 2

[0162]

[0163] In the present embodiment, a normalized SAR value greater than 1.0 W / Kg is considered high. Referring to Tables 1 and 2, the SAR values ​​of the first and second antennas are relatively high. In particular, the first antenna achieves a normalized SAR value of 1.70 W / Kg at a resonant frequency of 2.61 GHz, which is considered high.

[0164] Figure 8a-8d is a schematic heat map of the first antenna, where Figure 8a and Figure 8b is the first resonance, Figure 8c and Figure 8d is the second resonance, Figure 8a and Figure 8c For the back, Figure 8b and Figure 8d For the bottom surface. Figure 8a-8d As shown, for the first antenna, the hotspot of the first resonance is concentrated at the main feed branch, the hotspot of the second resonance is concentrated at the coupled parasitic branch, and the hotspot of the second resonance is higher.

[0165] Figures 9a-9d is a schematic heat map of the second antenna, where Figure 9a and Figure 9b is the first resonance, Figure 9c and Figure 9d is the second resonance, Figure 9a and Figure 9c For the back, Figure 9b and Figure 9d For the bottom surface. Figure 9a-9d As shown, for the second antenna, the hot spots of the first resonance are more dispersed on the back surface and concentrated at the main feed branch on the bottom surface, while the hot spots of the second resonance are concentrated at the main feed branch on the back surface and are very dispersed on the bottom surface.

[0166] It should be noted that in the heat map, the lines outline the local structure of the electronic device, the overall background is black, and the elliptical white area surrounding it represents a concentrated area of ​​hotspots. The less white this area is, or the lighter the color at the center, the lower the concentration of hotspots; the more white this area is, or the darker the color at the center, the higher the concentration of hotspots.

[0167] In the embodiment of the present application, the first antenna and the second antenna can be connected via an RF connection line 24 to form a distributed antenna. A feed source 23 is provided on the first body 11a. The feed source 23 inputs an electrical signal to the first radiator 21 via a first feed point F1 and to the second radiator 22 via the RF connection line 24 and a second feed point F2. The two electrical signals are distributed with equal power. It should be understood that when the first radiator 21 and the second radiator 22 are fed with electrical signals via the same feed source 23 and the amplitudes of the two electrical signals are the same or nearly the same within a certain error range, they can be considered to be distributed with equal power.

[0168] The RF connection line 24 may be in the form of a cable or a flexible circuit board (FPC), etc. By controlling the length of the RF connection line 24 , the phase difference between the electrical signal reaching the first feeding point F1 and the second feeding point F2 can be controlled.

[0169] In another possible embodiment, by adding a phase shifter or other device capable of adjusting the phase of the wave to the RF connection line 24, the phase difference between the electrical signal reaching the first feeding point F1 and the second feeding point F2 can also be controlled. The location of the phase shifter is not specifically limited and, for example, can be disposed within the first body 11a or the second body 11b.

[0170] The phase difference between the electrical signals reaching the first radiator 21 and the second radiator 22 is controlled to simulate the SAR value and hotspot distribution of the antenna under different phase differences. For example, the phase difference can have three conditions: the same phase, a 90° difference, and an opposite phase. The SAR value results of the antenna can be obtained as shown in Table 3a, Table 3b, and Table 3c, respectively.

[0171] It should be noted that the "in phase", "90° phase difference" and "opposite phase" provided in the embodiments of the present application do not fix the numerical value of the phase difference. In fact, the phase difference can be limited to a range. For example, the range of the phase difference when "in phase" can be 0±10°, the range of the phase difference when "90° phase difference" can be 90°±10°, and the range of the phase difference when "opposite phase" can be 180°±10°.

[0172] Table 3a Same phase

[0173]

[0174] Table 3b Phase difference 90°

[0175]

[0176] Table 3c reverse phase

[0177]

[0178] Referring to Tables 3a-3c, it can be seen that in terms of simulation efficiency, overall, the efficiency of the anti-phase is higher than the efficiency of the 90° phase difference, which is higher than the efficiency of the same phase. In terms of SAR value, for the first resonance, the normalized SAR value under the same phase is high SAR, the SAR value under the 90° phase difference is low, and the SAR value under the anti-phase is lower than 1W / Kg, which is low SAR. For the second resonance, the SAR value is lower than 1W / Kg under the three phases, which is low SAR. Since the first resonance can be regarded as the CM mode of the slot antenna, the SAR value is relatively high. The purpose of this application is mainly to reduce the SAR value of the first resonance. Therefore, overall, the SAR value under the anti-phase is lower than the SAR value under the 90° phase difference, which is lower than the SAR value under the same phase, especially for the first resonance.

[0179] Comparing the SAR value of this distributed antenna with the SAR value of the single antenna fed with each electrical signal reveals that when the electrical signals reaching the first radiator 21 and the second radiator 22 are in phase, the first resonant SAR value of the distributed antenna is higher than that of the single antenna. When the electrical signals reaching the first radiator 21 and the second radiator 22 are in opposite phases, the SAR value of the distributed antenna is significantly lower than that of the single antenna. Therefore, providing a distributed antenna and controlling the phase difference between the electrical signals reaching the first radiator 21 and the second radiator 22 can achieve the goal of reducing the SAR value.

[0180] Figures 10a-10f is a schematic heat map of the antenna at the first resonant frequency at different phases, where Figure 10a-Figure 10c For the back, Figure 10d-10f For the bottom surface, Figure 10a and Figure 10d is in phase, Figure 10b and Figure 10e The phase difference is 90°. Figure 10c and Figure 10f For the opposite phase. Figure 10a-10f It can be seen that under the first resonance, from the same phase to the opposite phase, the hot spots on the back and bottom surfaces of the antenna are gradually dispersed, that is, the SAR value is gradually reduced.

[0181] Figures 11a-11f is a schematic heat map of the antenna at the second resonant frequency at different phases, where Figure 11a-Figure 11c For the back, Figure 11d-Figure 11f For the bottom surface, Figure 11a and Figure 11d is in phase, Figure 11b and Figure 11e The phase difference is 90°. Figure 11c and Figure 11f For the opposite phase. Figure 11a-Figure 11f It can be seen that under the second resonance, from the same phase to the opposite phase, the hot spots on the back and bottom surfaces of the antenna are always dispersed. Because the radiation branches are dispersed at both ends, the SAR value is always low.

[0182] Figure 12a-12f is the current distribution diagram of the antenna under different phases, where Figure 12a and Figure 12b is in phase, Figure 12c and Figure 12d The phase difference is 90°. Figure 12e and Figure 12f is the opposite phase, Figure 12a 、 Figure 12c 、 Figure 12e is the first resonance, Figure 12b 、 Figure 12d 、 Figure 12f is the second resonance. Figure 12a As shown, the current distribution on the first radiator 21 in the same direction can be considered the CM mode of the slot antenna, and the current distribution on the second radiator 22 in the same direction can be considered the CM mode of the slot antenna. The current distribution on the first radiator 21 and the second radiator 22 in the same direction can be considered the DM mode of the wire antenna. That is, at the first resonance, when the electrical signals reaching the first and second radiators are in phase, the common-mode mode of the single-sided slot antenna can be converted into the differential-mode mode of the wire antenna centered around the rotation axis 12 in the distributed antenna.

[0183] refer to Figure 12b As shown, the reverse distribution of current on the first radiator 21 can be regarded as the DM mode of the slot antenna, and the reverse distribution of current on the second radiator 22 can be regarded as the DM mode of the slot antenna. The current on the first radiator 21 and the second radiator 22 is distributed in the same direction, which can be regarded as the DM mode of the wire antenna. From the perspective of the main feeding branch with stronger current, the current on the main feeding branch of the first radiator 21 and the main feeding branch of the second radiator 22 is distributed in the same direction, which can be regarded as the DM mode of the wire antenna. That is, under the second resonance, when the electrical signals reaching the first radiator and the second radiator are in phase, the differential mode mode of the single-sided slot antenna can be converted into the differential mode mode of the wire antenna centered on the rotating shaft 12 in the distributed antenna.

[0184] refer to Figure 12cAs shown, the current distribution on the first radiator 21 in the same direction can be regarded as the CM mode of the slot antenna, and the current distribution on the second radiator 22 in the same direction can be regarded as the CM mode of the slot antenna. The current distribution on the first radiator 21 and the second radiator 22 in the same direction can be regarded as the DM mode of the wire antenna. Figure 12d As shown, the reverse current distribution on the first radiator 21 can be regarded as the DM mode of the slot antenna, and the reverse current distribution on the second radiator 22 can be regarded as the DM mode of the slot antenna. The current distribution on the first radiator 21 and the second radiator 22 in the same direction can be regarded as the DM mode of the wire antenna. That is, when the electrical signals reaching the first radiator and the second radiator differ by 90°, the common mode mode and differential mode mode of the single-sided slot antenna can be converted into the differential mode mode of the wire antenna centered on the rotating shaft 12 in the distributed antenna. Compared to Figure 12a and Figure 12b In the scheme, the differential mode or common mode of the antenna is the same, the difference lies in the amplitude of the current on both sides.

[0185] refer to Figure 12e As shown, the current on the first radiator 21 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the second radiator 22 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the first radiator 21 and the second radiator 22 are distributed in opposite directions, which can be regarded as the CM mode of the wire antenna. That is, under the first resonance, when the electrical signals reaching the first radiator and the second radiator are in opposite phases, the common mode mode of the single-sided slot antenna can be converted into the common mode mode of the wire antenna centered on the rotation axis 12 in the distributed antenna. Figure 12f As shown, the current of the main feeding branch of the first radiator 21 and the current of the main feeding branch of the second radiator 22 are distributed in opposite directions, that is, under the second resonance, when the electrical signals reaching the first radiator and the second radiator are in opposite phases, the differential mode of the single-sided slot antenna can be converted into the common mode mode of the wire antenna centered on the rotating shaft 12 in the distributed antenna.

[0186] It should be noted that "centered on the rotating axis" means that the currents on both sides of the rotating axis 12 are distributed in the same or opposite directions with the rotating axis 12 as the boundary. At the same time, in the embodiment of the present application, the structures of the first radiator 21 and the second radiator 22 can be regarded as axially symmetrical with the rotating axis, and this axial symmetry includes the symmetry of the positions of the gap, grounding point, and feeding point.

[0187] In summary, in an electronic device in an unfolded state, when the opening directions of the main feed branch ends of the first radiator and the second radiator are opposite, by controlling the phase difference of the electrical signal reaching the first radiator and the second radiator to be in antiphase, a common mode mode of the linear antenna can be formed, and a high-performance, broadband, low-SAR distributed antenna can be obtained. It should be understood that the larger the range of resonant frequencies where the system efficiency is above -5dB, that is, the wider the bandwidth, for the embodiments of the present application, high efficiency also brings about the effect of broadband.

[0188] Figure 13 This is a comparison diagram of the current distribution of the antenna in the unfolded state and the folded state. Figure 13 Therefore Figure 12e For example. Figure 13 As shown, in the unfolded state, when the current of the distributed antenna can form an axisymmetric distribution with the rotating shaft 12 as the axis, after folding, the first radiator 21 and the second radiator 22 are arranged in parallel and adjacent to each other, and the current distribution on the first radiator 21 and the second radiator 22 is in the same direction. Therefore, the influence between the radiating branches is minimized, and the antenna in the folded state can have excellent efficiency.

[0189] Figure 14 This is a comparison chart of the radiation efficiency of antennas of electronic devices in a folded state. Figure 15 The figure shows the system efficiency comparison of the antennas of electronic devices in the folded state, where C1 represents the same phase, C2 represents the phase difference of 90 degrees, and C3 represents the opposite phase. Figure 14 and Figure 15 As shown, the radiation efficiency of the antenna with a 90° phase difference and an anti-phase condition is similar, both significantly greater than the radiation efficiency of the antenna with the same phase. The system efficiency of the antenna with the anti-phase condition is higher than that with a 90° phase difference and the same phase. Therefore, when the main feed branch ends of the first radiator 21 and the second radiator 22 are opened in opposite directions, the antenna can achieve excellent efficiency in the folded state by controlling the phase difference of the electrical signals reaching the first radiator 21 and the second radiator 22 to be in opposite phases.

[0190] When the main feed branch tips of the first radiator 21 and the second radiator 22 are opened in opposite directions, the phase difference between the electrical signals reaching the first and second radiators 21 and 22 is controlled to be in opposite phases. Simulating the 5mm body SAR values ​​of the back and bottom surfaces of the electronic device in a folded state and normalizing them to a -5dB efficiency yields the antenna SAR results shown in Table 4a. Simulating the 5mm body SAR values ​​of the back and bottom surfaces of the first antenna on the first body 11a in a folded state and normalizing them to a -5dB efficiency yields the antenna SAR results shown in Table 4b.

[0191] Table 4a

[0192]

[0193] Table 4b

[0194]

[0195]

[0196] Comparing Table 4a and Table 4b, it can be seen that in the folded state, the SAR value of the distributed antenna provided in the embodiment of the present application is generally lower than the SAR value of using only the single antenna on the first body.

[0197] In summary, the embodiment of the present application provides an antenna for a foldable electronic device, in which a first radiator arranged on a first body and a second radiator arranged on a second body constitute a distributed antenna. When the opening directions of the ends of the main feed branches of the first radiator and the second radiator are opposite, the phase difference of the control electrical signal reaching the first radiator and the second radiator is in antiphase, so that when the electronic device is in an unfolded state, a common mode mode of the linear antenna can be formed, achieving the effects of high efficiency, wide bandwidth, and low SAR value; at the same time, when the electronic device is in a folded state, since the current directions of the adjacent parallel radiating branches on the first body and the second body remain consistent, high efficiency and low SAR value can be achieved.

[0198] Scene 2

[0199] Figure 16 This is another schematic diagram of the antenna structure. Figure 16 As shown, in the embodiment of the present application, the arrangement of the first radiator 21, the second radiator 22 and the four gaps can refer to the arrangement of the first radiator 21, the second radiator 22 and the four gaps. Figure 5 The structure of is not described here.

[0200] In the embodiment of the present application, the first feeding point F1 feeds the branch on the left side of the first slot 211, and the second feeding point F2 feeds the branch on the left side of the second slot 221, that is, the end opening direction of the main feeding branch of the first radiator 21 is to the right, and the end opening direction of the main feeding branch of the second radiator 22 is to the right, and the end opening directions of the two main feeding branches are the same.

[0201] When the electronic device is in the unfolded state, if the first radiator 21 and the second radiator 22 are not connected by an RF connection line, but an electrical signal is fed to the first radiator 21 alone, the first radiator 21 and the ground can constitute a first antenna, which is a slot antenna. Similarly, if an electrical signal is fed to the second radiator 22 alone, the second radiator 22 and the ground can constitute a second antenna, which is a slot antenna.

[0202] Figure 17is a return loss coefficient curve diagram of the first antenna and the second antenna, S11 and S22 represent the return loss characteristics of the first antenna and the second antenna respectively, and S12 represents the isolation between the first antenna and the second antenna. Figure 18 is the efficiency curve of the first antenna and the second antenna, E1 and E2 represent the system efficiency of the first antenna and the second antenna respectively, and R1 and R2 represent the radiation efficiency of the first antenna and the second antenna respectively. Figure 17 and Figure 18 As shown, when the first and second antennas are fed with electrical signals, their performance is comparable, with both antennas generating two resonances. The two center resonant frequencies of the two antennas coincide, with the first resonant frequency at 1.83 GHz and the second at 2.61 GHz. Furthermore, the isolation between the first and second antennas is less than -13 dB, indicating good isolation between the first and second antennas.

[0203] By simulating the 5mm body SAR values ​​of the first and second antennas on the back and bottom of the electronic device and normalizing them according to the -5dB efficiency, the SAR value results of the first antenna are shown in Table 5, and the SAR value results of the second antenna are shown in Table 6.

[0204] Table 5

[0205]

[0206] Table 6

[0207]

[0208]

[0209] Referring to Table 5 and Table 6, it can be seen that the SAR values ​​of the first antenna and the second antenna are relatively high. In particular, the normalized SAR value of the first antenna can reach 1.70 W / Kg when the resonant frequency is 2.61 GHz, which is a high SAR.

[0210] The heat map of the first antenna can be referred to Figure 8a-8d As shown, the hotspot of the first resonance is concentrated at the main feed branch, the hotspot of the second resonance is concentrated at the coupled parasitic branch, and the hotspot of the second resonance is higher.

[0211] Figure 19a-Figure 19d is a schematic heat map of the second antenna, where Figure 19a and Figure 19b is the first resonance, Figure 19c and Figure 19d is the second resonance, Figure 19a and Figure 19c For the back, Figure 19b and Figure 19d For the bottom surface. Figure 19a-Figure 19dAs shown, for the second antenna, the hot spots of the first resonance are more dispersed on the back surface and concentrated at the main feed branch on the bottom surface, while the hot spots of the second resonance are concentrated at the main feed branch on the back surface and are very dispersed on the bottom surface.

[0212] In the embodiment of the present application, the configuration of the feed source 23 and the RF connection line 24 may refer to the structure in scenario 1 and will not be repeated here.

[0213] The phase difference between the electrical signals reaching the first radiator 21 and the second radiator 22 is controlled to simulate the SAR value and hotspot distribution of the antenna under different phase differences. For example, the phase difference can have three conditions: the same phase, a 90° difference, and an opposite phase. The SAR value results of the antenna can be obtained as shown in Table 7a, Table 7b, and Table 7c, respectively.

[0214] Table 7a Same phase

[0215]

[0216] Table 7b Phase difference 90°

[0217]

[0218] Table 7c reverse phase

[0219]

[0220] As shown in Tables 7a-7c, the simulated efficiency is generally higher with in-phase signals than with a 90° phase difference, which is higher than with out-of-phase signals. Regarding SAR values, for the first resonance, the in-phase SAR value is lower than the 90° phase difference, which is lower than the out-of-phase SAR value. For the second resonance, the normalized SAR values ​​are all below 1 W / Kg with in-phase signals, indicating low SAR.

[0221] Comparing the SAR value of this distributed antenna with the SAR value of the single antenna fed with each electrical signal reveals that when the electrical signals reaching the first and second radiators are in opposite phases, the first resonant SAR value of the distributed antenna is higher than that of the single antenna. When the electrical signals reaching the first and second radiators are in phase, the SAR value of the distributed antenna is significantly lower than that of the single antenna. Therefore, by providing a distributed antenna and controlling the phase difference between the electrical signals reaching the first and second radiators, the SAR value can be reduced.

[0222] Figure 20a-20f is a schematic heat map of the antenna at the first resonant frequency at different phases, where Figure 20a-Figure 20c For the back, Figure 20d-Figure 20e For the bottom surface, Figure 20a and Figure 20d is in phase, Figure 20b and Figure 20e The phase difference is 90°. Figure 20c and Figure 20f For the opposite phase. Figure 20a-20f It can be seen that under the first resonance, from the same phase to the opposite phase, the hot spots on the back and bottom surfaces of the antenna are gradually concentrated, that is, the SAR value is gradually increasing.

[0223] Figure 21a-Figure 21f is a schematic heat map of the antenna at the second resonant frequency at different phases, where Figure 21a-Figure 21c For the back, Figure 21d-Figure 21f For the bottom surface, Figure 21a and Figure 21d is in phase, Figure 21b and Figure 21e The phase difference is 90°. Figure 21c and Figure 21f For the opposite phase. Figure 21a-Figure 21f It can be seen that under the second resonance, the hot spot tends to be concentrated on the first radiator 21, and there is also current distribution on the second radiator 22. The hot spot concentration area on the first radiator 21 and the hot spot concentration area on the second radiator 22 are separated by a radiation branch of the first radiator 21, so the SAR value is relatively low.

[0224] Figure 22a-22f is the current distribution diagram of the antenna under different phases, where Figure 22a-22b is in phase, Figure 22c-22d The phase difference is 90°. Figure 22e-22f is the opposite phase, Figure 22a 、 Figure 22c 、 Figure 22e is the first resonance, Figure 22b 、 Figure 22d 、 Figure 22f The second resonance is shown in Figure 2. It should be noted that due to the asymmetrical structure of the two radiators on either side of the shaft, the current distribution on the first radiator 21 and the second radiator 22 is uneven. The thicker lines in the figure indicate a greater current distribution. When determining whether the antenna is in CM or DM mode based on the current distribution, the branch with the greater current distribution can be prioritized.

[0225] refer to Figure 22a As shown, the current on the first radiator 21 is distributed in the same direction, which can be considered the CM mode of the slot antenna. The current on the second radiator 22 is distributed in the same direction, which can be considered the CM mode of the slot antenna. The current on the coupled parasitic branch with a stronger current on the first radiator 21 and the coupled parasitic branch with a stronger current on the second radiator 22 are distributed in opposite directions, which can be considered the CM mode of the wire antenna. That is, at the first resonance, when the electrical signals reaching the first radiator 21 and the second radiator 22 are in phase, the common mode mode of the single-sided slot antenna can be converted into the common mode mode of the wire antenna centered on the rotating shaft 12 in the distributed antenna.

[0226] refer to Figure 22b As shown, the current on the first radiator 21 is distributed in opposite directions, which can be considered the DM mode of the slot antenna. The current on the second radiator 22 is distributed in opposite directions, which can be considered the DM mode of the slot antenna. The current on the main feed branch with stronger current on the first radiator 21 and the main feed branch with stronger current on the second radiator 22 are distributed in opposite directions, which can be considered the CM mode of the wire antenna. That is, at the second resonance, when the electrical signals reaching the first radiator 21 and the second radiator 22 are in phase, the differential mode mode of the single-sided slot antenna can be converted into the common mode mode of the wire antenna in the distributed antenna.

[0227] refer to Figure 22c As shown, the current on the first radiator 21 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the second radiator 22 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the first radiator 21 and the second radiator 22 is distributed in the same direction, which can be regarded as the DM mode of the wire antenna. Figure 22d As shown, the reverse distribution of current on the first radiator 21 can be regarded as the DM mode of the slot antenna, and the reverse distribution of current on the second radiator 22 can be regarded as the DM mode of the slot antenna. The current on the main feed branch of the second radiator 22 is stronger, and the current on the main feed branch of the first radiator 21 and the current on the main feed branch of the second radiator 22 are distributed in the same direction, which can be regarded as the DM mode of the wire antenna. That is, when the electrical signals reaching the first radiator 21 and the second radiator 22 differ by 90°, the common mode mode and differential mode mode of the single-sided slot antenna can be converted into the differential mode mode of the wire antenna in the distributed antenna. Compared to Figure 22e and Figure 22f The difference lies in the amplitude of the current on both sides.

[0228] refer to Figure 22e As shown, the current on the first radiator 21 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the second radiator 22 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the first radiator 21 and the current on the second radiator 22 are distributed in the same direction, which can be regarded as the DM mode of the wire antenna. That is, under the first resonance, when the electrical signals reaching the first radiator 21 and the second radiator 22 are in opposite phases, the common mode mode of the single-sided slot antenna can be converted into the differential mode mode of the wire antenna centered on the rotation axis 12 in the distributed antenna. Figure 22fAs shown, the current on the first radiator 21 is distributed in opposite directions, which can be considered the DM mode of the slot antenna. The current on the second radiator 22 is distributed in opposite directions, which can be considered the DM mode of the slot antenna. The current on the main feed branch with stronger current on the first radiator 21 and the main feed branch with stronger current on the second radiator 22 are distributed in the same direction, which can form the DM mode of the wire antenna. That is, at the second resonance, when the electrical signals reaching the first radiator 21 and the second radiator 22 are in opposite phases, the differential mode mode of the single-sided slot antenna can be converted into the differential mode mode of the wire antenna in the distributed antenna.

[0229] In summary, when the opening directions of the main feed branch ends of the first radiator 21 and the second radiator 22 are the same for an electronic device in the unfolded state, by controlling the phase difference of the electrical signals reaching the first radiator 21 and the second radiator 22 to be in phase, the first resonant current of the distributed antenna can be symmetrically distributed in opposite directions about the rotation axis when the electronic device is in the unfolded state. Therefore, when the electronic device is in the folded state, the current distribution of adjacent parallel radiating branches on the first and second bodies is in the same direction. When the electronic device is in the unfolded state, the second resonant current is symmetrically distributed in the same direction about the rotation axis. Although the current distribution is uneven, when the electronic device is in the folded state, the current distribution of adjacent parallel radiating branches on the first and second bodies is generally in the same direction. Thus, a high-performance, low-SAR antenna can be obtained.

[0230] Scene 3

[0231] Figure 23 This is another structural diagram of an antenna provided in an embodiment of the present application. Figure 23 As shown, in the embodiment of the present application, the arrangement of the first radiator 21, the second radiator 22 and the four gaps can refer to the arrangement of the first radiator 21, the second radiator 22 and the four gaps. Figure 5 The structure of is not described here.

[0232] In the embodiment of the present application, the first feeding point F1 feeds the branch on the left side of the first slot 211, and the second feeding point F2 feeds the branch on the right side of the second slot 221, that is, the end opening direction of the main feeding branch of the first radiator 21 is to the right, and the end opening direction of the main feeding branch of the second radiator 22 is to the left, and the end opening directions of the two main feeding branches are opposite.

[0233] When the electronic device is in the unfolded state, if the first radiator 21 and the second radiator 22 are not connected by an RF connection line, but an electrical signal is fed to the first radiator 21 alone, the first radiator 21 and the ground can constitute a first antenna, which is a slot antenna. Similarly, if an electrical signal is fed to the second radiator 22 alone, the second radiator 22 and the ground can constitute a second antenna, which is a slot antenna.

[0234] Figure 24is a return loss coefficient curve diagram of the first antenna and the second antenna, S11 and S22 represent the return loss characteristics of the first antenna and the second antenna respectively, and S12 represents the isolation between the first antenna and the second antenna. Figure 25 is the efficiency curve of the first antenna and the second antenna, E1 and E2 represent the system efficiency of the first antenna and the second antenna respectively, and R1 and R2 represent the radiation efficiency of the first antenna and the second antenna respectively. Figure 24 and Figure 25 As shown, when the first and second antennas are fed with electrical signals, their performance is comparable, with both antennas generating two resonances. The two center resonant frequencies of the two antennas coincide, with the first resonant frequency at 1.86 GHz and the second at 2.6 GHz. Furthermore, the isolation between the first and second antennas is less than -13 dB, indicating good isolation between the first and second antennas.

[0235] By simulating the 5mm body SAR values ​​of the first and second antennas on the back and bottom of the electronic device and normalizing them according to the -5dB efficiency, the SAR value results of the first antenna are shown in Table 8, and the SAR value results of the second antenna are shown in Table 9.

[0236] Table 8

[0237]

[0238]

[0239] Table 9

[0240]

[0241] Referring to Table 8 and Table 9, it can be seen that the SAR values ​​of the first antenna and the second antenna are relatively high. In particular, the normalized SAR value of the first antenna can reach 1.20 W / Kg when the resonant frequency is 1.86 GHz, which is a high SAR.

[0242] Figure 26a-26d is a schematic heat map of the first antenna, where Figure 26a and Figure 26b is the first resonance, Figure 26c and Figure 26d is the second resonance, Figure 26a and Figure 26c For the back, Figure 26b and Figure 26d For the bottom surface. Figure 26a-26d As shown, for the first antenna, the hotspot of the first resonance is concentrated at the main feed branch, the hotspot of the second resonance is concentrated at the coupled parasitic branch, and the hotspot of the first resonance is higher.

[0243] The heat map of the second antenna can be referenced Figure 19a-Figure 19dAs shown, the hot spots of the first resonance are more dispersed on the back side, tending to be concentrated at the main feed branch node, and concentrated at the coupled parasitic branch node on the bottom side. The hot spots of the second resonance are concentrated at the coupled parasitic branch node on the back side and are very dispersed on the bottom side.

[0244] In the embodiment of the present application, the configuration of the feed source 23 and the RF connection line 24 may refer to the structure in scenario 1 and will not be repeated here.

[0245] The phase difference between the electrical signals reaching the first radiator 21 and the second radiator 22 is controlled to simulate the SAR value and hotspot distribution of the antenna under different phase differences. For example, the phase difference can have three conditions: the same phase, a 90° difference, and an opposite phase. The SAR value results of the antenna can be obtained as shown in Table 10a, Table 10b, and Table 10c, respectively.

[0246] Table 10a Same phase

[0247]

[0248] Table 10b Phase difference 90°

[0249]

[0250] Table 10c Reverse Phase

[0251]

[0252]

[0253] Referring to Tables 10a-10c, it can be seen that in terms of simulation efficiency, overall, the efficiency of the anti-phase is higher than the efficiency of the phase difference of 90°, which is higher than the efficiency of the same phase. In terms of SAR value, for the first resonance, the normalized SAR value is lower than 1W / Kg under the phase difference of 90° and the anti-phase, which is a low SAR, and the normalized SAR value is higher under the same phase; for the second resonance, the SAR value of the anti-phase is generally lower than the SAR value of the phase difference of 90° and lower than the SAR value of the same phase. Overall, the SAR value of the anti-phase is generally lower than the SAR value of the phase difference of 90° and lower than the SAR value of the same phase, especially for the second resonance. It should be noted that in scenarios one and two, the SAR reduction effect is mainly reflected in the first resonance, while in this scenario, the SAR reduction effect is mainly reflected in the second resonance. This is because the structure of the radiation branch in scenario three is different, and the system efficiency of the second resonance is higher.

[0254] Figure 27a-Figure 27f is a schematic heat map of the antenna at the first resonant frequency at different phases, where Figure 27a-27c For the back, Figure 27d-27f For the bottom surface, Figure 27a and Figure 27d is in phase, Figure 27b and Figure 27e The phase difference is 90°. Figure 27c and Figure 27f For the opposite phase. Figure 27a-Figure 27f It can be seen that under the first resonance, from the same phase to the opposite phase, the hot spots on the back surface are always dispersed, and the hot spots on the bottom surface are gradually dispersed, so the SAR is reduced.

[0255] Figure 28a-28f is a schematic heat map of the antenna at the second resonant frequency at different phases, where Figure 28a-28c For the back, Figure 28d-Figure 28f For the bottom surface, Figure 28a and Figure 28d is in phase, Figure 28b and Figure 28e The phase difference is 90°. Figure 28c and Figure 28f For the opposite phase. Figure 28a-28f It can be seen that under the second resonance, the hot spots on the back and bottom surfaces are gradually dispersed from the same phase to the opposite phase, so the SAR value is reduced.

[0256] Figure 29a-29f is the current distribution diagram of the antenna at different phases, where Figure 29a-29b is in phase, Figure 29c-29d The phase difference is 90°. Figure 29e-29f is the opposite phase, Figure 29a 、 Figure 29c 、 Figure 29e is the first resonance, Figure 29b 、 Figure 29d 、 Figure 29f is the second resonance. Figure 29a As shown, the current distribution on the first radiator 21 in the same direction can be considered the CM mode of the slot antenna, and the current distribution on the second radiator 22 in the same direction can be considered the CM mode of the slot antenna. The current distribution on the first radiator 21 and the second radiator 22 in the same direction can be considered the DM mode of the wire antenna. That is, at the first resonance, when the electrical signals reaching the first radiator 21 and the second radiator 22 are in phase, the common mode mode of the single-sided slot antenna can be converted into the differential mode mode of the wire antenna centered on the rotation axis 12 in the distributed antenna.

[0257] refer to Figure 29bAs shown, the current on the first radiator 21 is distributed in opposite directions, which can be considered the DM mode of the slot antenna. The current on the second radiator 22 is distributed in opposite directions, which can be considered the DM mode of the slot antenna. The current on the main feed branch of the first radiator 21 and the current on the main feed branch of the second radiator 22 are distributed in the same direction, which can be considered the DM mode of the slot antenna. That is, at the second resonance, when the electrical signals reaching the first radiator 21 and the second radiator 22 are in phase, the differential mode mode of the single-sided slot antenna can be converted into the differential mode mode of the wire antenna centered on the rotating shaft 12 in the distributed antenna.

[0258] refer to Figure 29c As shown, the current on the first radiator 21 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the second radiator 22 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the first radiator 21 and the second radiator 22 is distributed in the same direction, which can be regarded as the DM mode of the wire antenna. Figure 29d As shown, the reverse distribution of current on the first radiator 21 can be regarded as the DM mode of the slot antenna, and the reverse distribution of current on the second radiator 22 can be regarded as the DM mode of the slot antenna. The current on the main feed branch of the first radiator 21 and the current on the main feed branch of the second radiator 22 are distributed in the same direction, which can be regarded as the DM mode of the slot antenna. That is, when the electrical signals reaching the first radiator 21 and the second radiator 22 differ by 90°, the common mode mode and differential mode mode of the single-sided slot antenna can be converted into the differential mode mode of the wire antenna centered on the rotating shaft 12 in the distributed antenna. Compared to Figure 29a and Figure 29b The difference is that the amplitude of the current on both sides is different.

[0259] refer to Figure 29e As shown, the current on the first radiator 21 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the second radiator 22 is distributed in the same direction, which can be regarded as the CM mode of the slot antenna. The current on the first radiator 21 and the second radiator 22 are distributed in opposite directions, which can be regarded as the CM mode of the wire antenna. That is, under the first resonance, when the electrical signals reaching the first radiator and the second radiator are in opposite phases, the common mode mode of the single-sided slot antenna can be converted into the common mode mode of the wire antenna centered on the rotation axis 12 in the distributed antenna. Figure 29fAs shown, the reverse current distribution on the first radiator 21 can be considered the DM mode of the slot antenna, and the reverse current distribution on the second radiator 22 can be considered the DM mode of the slot antenna. The reverse current distribution on the main feed branch of the first radiator 21 and the main feed branch of the second radiator 22 can be considered the CM mode of the wire antenna. That is, at the second resonance, when the electrical signals reaching the first and second radiators are in opposite phases, the differential mode mode of the single-sided slot antenna can be converted into the common mode mode of the wire antenna centered on the rotating shaft 12 in the distributed antenna.

[0260] In summary, the embodiment of the present application provides an antenna for a foldable electronic device, in which a first radiator arranged on a first body and a second radiator arranged on a second body constitute a distributed antenna. When the opening directions of the ends of the main feed branches of the first radiator and the second radiator are relative, the phase difference of the control electrical signal reaching the first radiator and the second radiator is in anti-phase, so that when the electronic device is in an unfolded state, a common mode mode of the linear antenna can be formed, achieving the effects of high efficiency, wide bandwidth, and low SAR value; at the same time, when the electronic device is in a folded state, since the current directions of the adjacent parallel radiating branches on the first body and the second body remain consistent, high efficiency and low SAR value can be achieved.

[0261] It should be noted that in the above three scenarios, the first radiator and the second radiator on the foldable electronic device can be in an axisymmetric structure to achieve better efficiency and lower SAR value. However, in practice, it is not required that the first radiator and the second radiator are both in a strictly axisymmetric structure, nor is it required that the resonances of the first radiator and the second radiator on one side completely coincide. The radiators on both sides are required to be composed of main feed branches and coupled parasitic branches. By controlling the phase difference reaching the radiators on both sides, the differential mode and common mode of the slot antenna on the single-sided antenna can be made to constitute the common mode of the wire antenna, so as to achieve high efficiency and low SAR value of the antenna, that is, fall within the protection scope of the embodiments of the present application.

[0262] In addition, the resonant frequency of the antenna provided by the embodiment of the present application is not limited to the 1.8 GHz and 2.6 GHz involved in the above-mentioned embodiment. By changing the electrical length of the first radiator and the second radiator, changing the position of the slot, and setting a tuning element, the resonant frequency of the antenna can be changed, so that the antenna provided by the embodiment of the present application is applicable to different frequency bands. The antenna provided by the embodiment of the present application is not limited to setting two radiators as a distributed antenna. In fact, there can be more radiators. In addition to being suitable for foldable electronic devices that are folded once, it can also be suitable for foldable electronic devices that are folded twice or more.

[0263] The antenna provided in the above-mentioned embodiment of the present application is applied to a foldable electronic device. By constructing a symmetrical structure of the radiators on both sides of the rotating shaft, a common mode mode of the linear antenna is achieved, thereby achieving high efficiency and low SAR value of the antenna. On this basis, the present application also provides some embodiments, by constructing a symmetrical antenna structure and controlling the phase difference on other non-foldable electronic devices to achieve the common mode of the linear antenna, thereby achieving high efficiency and low SAR value of the antenna. Among them, other non-foldable electronic devices can be, for example, mobile phones, tablet computers, etc.

[0264] Hereinafter, another antenna structure provided by the present application will be described in detail by taking a tablet computer as an example with reference to specific drawings and embodiments.

[0265] Example 2

[0266] Figure 30 This is a schematic diagram of the structure of a wire antenna provided in one embodiment of the present application. Figure 30 As shown, the wire antenna may include a first radiator 21, a first feed source 23 and a first feeding point F1. The wire antenna may be a T-shaped wire antenna, that is, a wire antenna with a constant ground point provided on the radiator. The first radiator 21 may be arranged at the edge of the electronic device or near the edge of the electronic device, and may be made of a flexible circuit board, or may be made by laser, or may be made by a spraying process. The mainboard or floor (the filled area in the figure) is arranged inside the electronic device, with a certain gap between it and the first radiator 21. The first radiator 21 may be electrically connected to the mainboard by means of metal shrapnel, etc., thereby realizing feeding and grounding of the antenna.

[0267] The locations of the first feed point F1 and the grounding point are not specifically limited in the wire antenna provided in the embodiments of the present application. In a specific embodiment, the length of the first radiator 21 can be 28 mm, and the grounding point is located in the right half of the first radiator 21 and is 9 mm away from the right end of the first radiator 21.

[0268] Feeding an electrical signal into the first antenna can simulate the resonant frequency of the first antenna. Figure 31 for Figure 30 The return loss coefficient curve corresponding to the provided antenna is Figure 32 for Figure 30 The efficiency curve of the provided antenna, where the solid line represents the system efficiency and the dotted line represents the radiation efficiency. Figure 31 and Figure 32 As shown, the wire antenna can generate two resonances, the first resonance frequency is 1.91 GHz, and the second resonance frequency is 3.58 GHz.

[0269] Figure 33a-Figure 33b for Figure 30 The current distribution diagram of the antenna is provided. Figure 33ais the first resonance, Figure 33b is the second resonance, where the solid line refers to the current on the radiator and the dotted line refers to the current on the motherboard. Figure 33a As shown, when the antenna is in the first resonance, the current is distributed in the first radiator 21 in the opposite direction, that is, the first resonance is the common mode of the wire antenna. Figure 33b As shown, when the antenna is in the second resonance, the current is distributed in the same direction on the first radiator 21, that is, the second resonance is the differential mode of the linear antenna.

[0270] Taking the first antenna positioned near the bottom frame of an electronic device as an example, the 5mm body SAR values ​​of the first antenna on the back and bottom of the electronic device were simulated and normalized according to the -5dB efficiency. The SAR value results of the first antenna are shown in Table 11.

[0271] Table 11

[0272]

[0273] Referring to Table 11, it can be seen that the normalized SAR value of the first antenna can reach 2.25 W / Kg when the resonant frequency is 3.58 GHz, which is a high SAR.

[0274] Figure 34a-Figure 34d is a schematic heat map of the first antenna, where Figure 34a and Figure 34b is the first resonance, Figure 34c and Figure 34d is the second resonance, Figure 34a and Figure 34c For the back, Figure 34b and Figure 34d For the bottom surface. Figure 34a-Figure 34d As shown, the backside hot spot of the first resonance is more concentrated, the bottom side hot spot of the second resonance is more concentrated, and the hot spot of the second resonance is more concentrated than that of the first resonance.

[0275] In order to reduce the SAR value of the above-mentioned linear antenna, the embodiment of the present application can realize a high-efficiency, low-SAR antenna by adding a second radiator to construct an axially symmetrical structure and controlling the phase difference between the electrical signal reaching the first radiator and the second radiator.

[0276] Below, in Figure 30 On the basis of the provided wire antenna, two different antennas are constructed through scenario four and scenario five, and the structure of the antenna provided in the embodiment of the present application is specifically described in conjunction with the accompanying drawings.

[0277] Scene 4

[0278] Figure 35 This is a schematic diagram of the structure of an antenna provided in one embodiment of the present application. Figure 35As shown, the antenna may include a feed source 23, a first radiator 21, a second radiator 22 and a third radiator 25. The first radiator 21 and the second radiator 22 are respectively arranged on the left and right sides of the third radiator 25. The first radiator 21 inputs electrical signals through the first feeding point F1, and the second radiator 22 inputs electrical signals through the second feeding point F2. The first feeding point F1 and the second feeding point F2 are connected by a radio frequency connecting line 24, and the third radiator 25 is grounded.

[0279] The first radiator 21 and the second radiator 22 can be arranged axially symmetrically with respect to the third radiator 25, and the first feeding point F1 and the second feeding point F2 can also be arranged symmetrically. The grounding point of the first radiator 21 can be located on the side of the first feeding point F1 facing the third radiator 25, and the grounding point of the second radiator 22 can be located on the side of the second feeding point F2 facing the third radiator 25.

[0280] The lengths of the first radiator 21 and the second radiator 22 are not specifically limited in the embodiment of the present application and can be, for example, greater than 20 mm. The length of the third radiator 25 is less than that of the first radiator 21 and the second radiator 22. If the length of the third radiator 25 is too long, the resonance generated by it may affect the resonance of the first radiator 21 and the second radiator 22. If the length is too short, the first radiator 21 and the second radiator 22 may couple and affect the antenna performance. In one possible example, the length of the third radiator 25 can be between 5 mm and 10 mm. The positions of the feeding points and grounding points on the first radiator 21 and the second radiator 22 are not specifically limited in the embodiment of the present application.

[0281] In a specific embodiment, the lengths of the first and second radiators 21, 22 can be 28 mm, the distance between the first and second radiators 21, 22 can be 8 mm, and the length of the third radiator 25 can be 6 mm. A 25 nH inductor can be connected in series with the third radiator 25 and then to ground. This will generate a new resonance in the third radiator 25, which can be tuned using this inductance to lower the efficiency of the first resonance and become incompatible with the primary resonance efficiency. The distance between the grounding point of the first radiator 21 and the right end of the first radiator 21 can be 9 mm, and the distance between the grounding point of the second radiator 22 and the left end of the second radiator 22 can be 9 mm.

[0282] The phase difference between the electrical signal reaching the first feeding point F1 and the second feeding point F2 can be controlled by controlling the length of the RF connection line 24 or connecting a phase shifter to the RF connection line 24. By controlling the phase difference between the electrical signal reaching the first radiator 21 and the second radiator 22, the SAR value and hotspot distribution of the antenna under different phase differences can be simulated. For example, the phase difference can have three conditions: in phase, 90° phase difference, and anti-phase. The efficiency of the antenna under different phases can be obtained.

[0283] Figure 36 for Figure 35 The radiation efficiency curve of the antenna provided at different phases, Figure 37 for Figure 35 The system efficiency curves of the antenna provided at different phases, C1 represents the same phase, C2 represents a 90° phase difference, and C3 represents the opposite phase. Figure 36 and Figure 37 As shown, the antenna's radiation efficiency is relatively high when the phases are aligned and 90° apart, while it is lower when the phases are opposite. The system efficiency of the antenna when aligned is higher than when the phases are 90° apart or opposite. Therefore, the antenna performs best when the electrical signals arrive at the first radiator 21 and the second radiator 22 in phase.

[0284] Figure 38a-Figure 38b is the current distribution diagram of the antenna under the same phase, where Figure 38a is the first resonance, Figure 38b is the second resonance. Figure 38a As shown, in the same phase, in the first resonance of the antenna, the current on the first radiator 21 is distributed in opposite directions, the current on the second radiator 22 is distributed in opposite directions, and the current on the first radiator 21 and the second radiator 22 are distributed in opposite directions as a whole. Figure 38b As shown, in the same phase, when the antenna is in the second resonance, the current is distributed in opposite directions on the first radiator 21 and the second radiator 22. Based on the current flow direction, it is not difficult to see that in the same phase, both the first resonance and the second resonance form a symmetrical distribution structure with the third radiator 25 as the axis, forming a common mode mode of the wire antenna.

[0285] By simulating the 5mm body SAR value of the antenna on the back and bottom of the electronic device and normalizing it according to the -5dB efficiency, the SAR value results of the antenna can be obtained as shown in Table 12.

[0286] Table 12

[0287]

[0288]

[0289] Referring to Table 12 and comparing it with Table 11, it can be seen that under the distributed line antenna with the same phase, the SAR values ​​of the back and bottom surfaces of the first resonance decrease significantly, the SAR value of the back surface of the second resonance remains unchanged, and the SAR value of the bottom surface decreases significantly.

[0290] Figure 39a-39d The schematic heat map of the antenna in phase, where Figure 39 and Figure 39b is the first resonance, Figure 39c and Figure 39d is the second resonance, Figure 39a and Figure 39c For the back, Figure 39b and Figure 39d For the bottom surface. Figure 39a-Figure 39b As shown, the hot spots of the first resonance are dispersed on both the back and bottom surfaces, the hot spot of the second resonance moves to the middle position where the third radiator is located, and the hot spots on the bottom surface are dispersed, so the overall SAR value is low.

[0291] Figure 40 This is a simplified schematic diagram of the antenna structure provided in one embodiment of the present application. Figure 40 It can be seen that the antenna provided in the embodiment of the present application includes a first radiator 21, a second radiator 22 and a third radiator 25. The third radiator 25 is located between the first radiator 21 and the second radiator 22, and the length of the third radiator 25 is less than the length of the first radiator 21 and the second radiator 22; the first radiator 21 inputs the electrical signal through the first feeding point F1, the second radiator 22 inputs the electrical signal through the second feeding point F2, the first feeding point F1 and the second feeding point F2 are connected by a radio frequency connecting line 24, the third radiator 25 is grounded, and the phases of the electrical signals reaching the first feeding point F1 and the second feeding point F2 are the same.

[0292] It should be noted that the first radiator 21 and the second radiator 22 can be arranged axially symmetrically with respect to the third radiator 25, and the first feed point F1 and the second feed point F2 can be arranged axially symmetrically with respect to the third radiator 25, to achieve a common mode antenna similar to a linear antenna. However, in practice, a strictly axially symmetrical structure between the first and second radiators is not required. When the first and second radiators are nearly axially symmetrical, a low SAR value close to that of a linear antenna common mode antenna can be achieved.

[0293] It should be noted that the location of the grounding point in the antenna is not specifically limited. The grounding point can be set to the right of the first feeding point F1 and to the left of the second feeding point F2 as described in the above specific embodiment, or the grounding point can also be reflected by a matching parallel inductor.

[0294] In summary, the embodiments of the present application provide an antenna for use in electronic devices, wherein a first radiator and a second radiator are arranged on both sides of a third radiator and are symmetrically distributed, and the phase difference between the electrical signals reaching the first radiator and the second radiator is controlled to be in the same phase, thereby forming a common mode mode of the linear antenna and achieving the effects of high efficiency, wide bandwidth, and low SAR value.

[0295] Scene 5

[0296] Figure 41 This is a schematic diagram of the structure of another antenna provided in one embodiment of the present application. Figure 41 As shown, the antenna may include a first radiator 21 and a second radiator 22. The first radiator 21 and the second radiator 22 have the same structure and are arranged in a left-right arrangement. The first radiator 21 receives an electrical signal through a first feed point F1, and the second radiator 22 receives an electrical signal through a second feed point F2. The first feed point F1 and the second feed point F2 are connected by a radio frequency connection line 24.

[0297] The lengths of the first radiator 21 and the second radiator 22 are not specifically limited in this embodiment of the present application and can, for example, be greater than 20 mm. If the distance between the first radiator 21 and the second radiator 22 is too large, it is not conducive to the compact arrangement of antennas on electronic devices. If the distance is too small, coupling between the first radiator 21 and the second radiator 22 may affect antenna performance. In one possible example, the distance between the first radiator 21 and the second radiator 22 can be between 6 mm and 12 mm. The locations of the feeding points and grounding points on the first radiator 21 and the second radiator 22 are not specifically limited in this embodiment of the present application.

[0298] In a specific embodiment, the length of the first radiator 21 and the second radiator 22 can be 28 mm, the distance between the first radiator 21 and the second radiator 22 is 8 mm, the distance between the grounding point of the first radiator 21 and the right end of the first radiator 21 can be 9 mm, and the distance between the grounding point of the second radiator 22 and the left end of the second radiator 22 can be 9 mm.

[0299] The phase difference between the electrical signal reaching the first feeding point F1 and the second feeding point F2 can be controlled by controlling the length of the RF connection line 24 or connecting a phase shifter to the RF connection line 24. By controlling the phase difference between the electrical signal reaching the first radiator 21 and the second radiator 22, the SAR value and hotspot distribution of the antenna under different phase differences can be simulated. For example, the phase difference can have three conditions: in phase, 90° phase difference, and anti-phase. The efficiency of the antenna under different phases can be obtained.

[0300] Figure 42 for Figure 41 The radiation efficiency curve of the antenna provided at different phases, Figure 43 for Figure 41 The system efficiency curves of the antenna provided at different phases, C1 represents the same phase, C2 represents a 90° phase difference, and C3 represents the opposite phase. Figure 42 and Figure 43 As shown, when the electrical signals reach the first radiator 21 and the second radiator 22 in the same phase, the system efficiency of the antenna is the highest. However, the system efficiency under the same phase and the opposite phase differs by about 1 dB, which is a small difference.

[0301] Figure 44a-Figure 44b is the current distribution diagram of the antenna under the same phase, where Figure 44a is the first resonance, Figure 44b is the second resonance. Figure 44a As shown, in the same phase, the current on the first radiator 21 of the antenna at the first resonance is distributed in opposite directions, and the current on the second radiator 22 is distributed in opposite directions. The currents on the first radiator 21 and the second radiator 22 are distributed in opposite directions as a whole, which can be regarded as forming a common mode of the wire antenna. Figure 44b As shown, in the same phase, for the antenna in the second resonance, the current is distributed in the first radiator 21 and the second radiator 22 in the same direction, which can be regarded as forming a differential mode of the linear antenna.

[0302] It should be noted that the dotted arrows in the figure represent the induced current on the motherboard. The position without the arrow represents that the current is weaker at that position. The arrows in the figure only indicate the distribution of the current, and the length of the arrows does not represent the strength of the current.

[0303] By simulating the 5mm body SAR value of the antenna on the back and bottom of the electronic device and normalizing it according to the -5dB efficiency, the SAR value results of the antenna can be obtained as shown in Table 13.

[0304] Table 13

[0305]

[0306] Figure 45a-45d is a schematic heat map of the antenna under the same phase, where Figure 45a and Figure 45b is the first resonance, Figure 45c and Figure 45d is the second resonance, Figure 45a and Figure 45c For the back, Figure 45b and Figure 45d For the bottom surface. Figure 45a-45d As shown, the hot spots of the first resonance are relatively dispersed on the back and bottom surfaces, while the hot spots of the second resonance on the back surface are very concentrated.

[0307] Figure 46a-Figure 46b is the current distribution diagram of the antenna under reverse phase, where Figure 46ais the first resonance, Figure 46b is the second resonance. Figure 46a As shown, in the opposite phase, the current of the antenna at the first resonance is distributed in the opposite direction on the first radiator 21 and the second radiator 22, which can be regarded as forming a common mode of the wire antenna. Figure 46b As shown, in the antenna at the second resonance under anti-phase conditions, the current is distributed in opposite directions on the first radiator 21 and the second radiator 22 , which can be regarded as forming a common mode of the linear antenna.

[0308] By simulating the 5mm body SAR values ​​of the back and bottom surfaces of the antenna and normalizing them according to the -5dB efficiency, the SAR value results of the antenna are shown in Table 14.

[0309] Table 14

[0310]

[0311]

[0312] Referring to Table 14 and comparing it with Table 13, it can be seen that the SAR value of the second resonance in the opposite phase is significantly lower than the SAR value of the second resonance in the same phase, with a difference of more than 3dB.

[0313] Figure 47a-47d is a schematic heat map of the antenna under reverse phase, where Figure 47a and Figure 47b is the first resonance, Figure 47c and Figure 47d is the second resonance, Figure 47a and Figure 47c For the back, Figure 47b and Figure 47d For the bottom surface. Figure 47a-Figure 47b As shown, the hot spots of the first resonance are concentrated on the back surface and are more dispersed on the bottom surface. The hot spots on the back surface and the bottom wall of the second resonance are both very dispersed, and the SAR value is low.

[0314] Overall, although the system efficiency of the antenna is higher when in phase than when out of phase, the SAR value of the antenna in phase is much higher than that of the antenna in phase. A small difference in system efficiency is acceptable, but a 3dB difference in SAR value is unacceptable. Therefore, the out of phase with a lower SAR value is selected. That is, when the first radiator 21 and the second radiator 22 are arranged in parallel, the phase difference of the electrical signal reaching the first radiator and the second radiator can be controlled to be out of phase, thereby reducing the antenna SAR value.

[0315] Figure 48 This is a simplified schematic diagram of the antenna structure provided in one embodiment of the present application. Figure 48It can be seen that the antenna provided in the embodiment of the present application includes a first radiator 21 and a second radiator 22. The first radiator 21 inputs an electrical signal through the first feeding point F1, and the second radiator 22 inputs an electrical signal through the second feeding point F2. The first feeding point F1 and the second feeding point F2 are connected by a radio frequency connecting line 24, and the phases of the electrical signals reaching the first feeding point F1 and the second feeding point F2 are reversed.

[0316] It should be noted that the first radiator 21 and the second radiator 22 may have the same structure and be arranged in left-right arrangement, and the position of the first feeding point F1 relative to the first radiator 21 and the position of the second feeding point F2 relative to the second radiator 22 may be the same.

[0317] It should be noted that the location of the grounding point in the antenna is not specifically limited. The grounding point can be set to the right of the first feeding point F1 and the right of the second feeding point F2 as described in the above specific embodiment, or the grounding point can also be reflected by a matching parallel inductor.

[0318] In summary, the embodiments of the present application provide an antenna for use in electronic devices, in which the first radiator and the second radiator have the same structure and are arranged in left and right positions. The phase difference between the electrical signals reaching the first radiator and the second radiator is controlled to be in opposite phases, thereby forming a common mode of the linear antenna and achieving high efficiency, wide bandwidth, and low SAR value.

[0319] The antenna provided in the embodiment of the present application is applied to an electronic device, and a first radiator and a second radiator are provided. By setting the first radiator and the second radiator to be an axially symmetrical structure and controlling the electrical signals reaching the first radiator and the second radiator to be in phase, or by setting the first radiator and the second radiator to be arranged left and right and controlling the electrical signals reaching the first radiator and the second radiator to be in opposite phases, the SAR value of the antenna can be reduced.

[0320] It should be noted that in the above embodiments, referring to the various figures, it can be seen that the feed source 23 is grounded, that is, the feeding form adopts symmetrical feeding, which can be understood as one end of the feed source is connected to the radiator and the other end is grounded. In another possible embodiment, Figure 49 This is a schematic diagram of the antenna structure provided in one embodiment of the present application, refer to Figure 49 As shown, the feed source 23 can be ungrounded, and the feeding form can adopt anti-symmetrical feed. Anti-symmetrical feed can be understood as that the positive and negative poles of the feed source are respectively connected to the two ends of the radiator, and the positive and negative poles of the feed source output the same signal amplitude and opposite phase, for example, the phase difference is 180°±10°. When using anti-symmetrical feeding, the phase difference between the signal source reaching the first radiator 21 and the second radiator 22 needs to be adjusted accordingly, which will not be elaborated here.

[0321] In summary, the antenna and foldable electronic device provided in the embodiment of the present application utilize the space on the two main bodies of the foldable electronic device to respectively set radiators, and the two radiators are connected by a radio frequency connecting line to form a distributed antenna. By controlling the phase difference of the signal fed into the radiators on both sides by the feed source, the current is distributed in opposite directions on the radiators on both sides of the rotating shaft in the unfolded state, thereby constructing the common mode mode of the outgoing antenna. In the folded state, the two radiators constitute adjacent parallel radiators, and the current on the parallel radiators is distributed in the same direction, thereby achieving high efficiency and low SAR value of the antenna. In addition, compared with setting antennas on each of the two main bodies of the foldable electronic device, the embodiment of the present application sets a distributed antenna to obtain more resonant modes and bandwidths.

[0322] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the embodiments of the present application have been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An antenna, characterized in that: Applicable to a foldable electronic device, the foldable electronic device includes a rotating shaft and a first body and a second body arranged on both sides of the rotating shaft, the antenna includes a feed source, a first radiator, a second radiator, a first feeding point, a second feeding point and a radio frequency connection line; The first radiator is disposed in the first body, and the second radiator is disposed in the second body. An end of the first radiator close to the rotating shaft is grounded, and an end of the second radiator close to the rotating shaft is grounded. The first radiator is fed with an electrical signal through the first feeding point, and the second radiator is fed with an electrical signal through the second feeding point. The first feeding point and the second feeding point are connected by the RF connection line. A first slit is provided on the first radiator, and a second slit is provided on the second radiator. The positions of the first feeding point and the second feeding point and the phases of the electrical signals at the first feeding point and the second feeding point are set to: The first feeding point and the second feeding point are both arranged between the first slot and the second slot, and the phases of the electrical signals at the first feeding point and the second feeding point are in opposite phases; or, The first feeding point is arranged on a side of the first slot away from the second slot, the second feeding point is arranged on a side of the second slot away from the first slot, and the phases of the electrical signals at the first feeding point and the second feeding point are in opposite phases; or, The first feeding point is set between the first gap and the second gap, and the second feeding point is set on the side of the second gap away from the first gap, or the first feeding point is set on the side of the first gap away from the second gap, and the second feeding point is set between the first gap and the second gap, and the phases of the electrical signals of the first feeding point and the second feeding point are in phase.

2. The antenna according to claim 1, wherein The antenna further includes a phase shifter connected between the first feeding point and the second feeding point.

3. The antenna according to claim 2, wherein: The phase shifter is disposed in the first body or the second body.

4. The antenna according to any one of claims 1 to 3, characterized in that: The first radiator and the second radiator are arranged axially symmetrically with respect to the rotation axis, and the first slot and the second slot are arranged axially symmetrically with respect to the rotation axis.

5. The antenna according to any one of claims 1 to 3, characterized in that: The first radiator is further provided with a third slit, and the second radiator is further provided with a fourth slit, the third slit is located on a side of the first slit away from the second radiator, and the fourth slit is located on a side of the second slit away from the first radiator; The first feeding point and the second feeding point are both arranged between the third slot and the fourth slot.

6. The antenna according to any one of claims 1 to 3, characterized in that: The radio frequency connection line includes a cable or a flexible circuit board.

7. The antenna according to any one of claims 1 to 3, characterized in that: When the foldable electronic device is in an unfolded state, the extension direction of the first radiator and the second radiator is perpendicular to the extension direction of the rotation axis, and the distance between the first radiator and the second radiator is smaller than the width of the rotation axis; When the foldable electronic device is in a folded state, the first radiator and the second radiator extend in the same direction, and the first radiator and the second radiator overlap in a thickness direction of the foldable electronic device.

8. The antenna according to claim 7, characterized in that When the foldable electronic device is in an unfolded state, the currents on the first radiator and the second radiator are distributed in opposite directions; when the foldable electronic device is in a folded state, the currents on the first radiator and the second radiator are distributed in the same direction.

9. The antenna according to claim 7, wherein: The first radiator is electrically connected to the rotation shaft and is grounded through the rotation shaft. The second radiator is electrically connected to the rotation shaft and is grounded through the rotation shaft.

10. The antenna according to any one of claims 1 to 3, characterized in that: There is a gap between the first radiator and the floor, and a groove is formed between the first radiator and the floor to form an electrical connection. There is a gap between the second radiator and the floor, and a groove is formed between the second radiator and the floor to form an electrical connection.

11. The antenna according to any one of claims 1 to 3, characterized in that: The first radiator is provided with a tuning switch, and the two tuning switches are respectively provided on both sides of the first slot; the second radiator is provided with a tuning switch, and the two tuning switches are respectively provided on both sides of the second slot.

12. A foldable electronic device, characterized in that: The invention comprises a rotating shaft, a first body and a second body arranged on both sides of the rotating shaft, and the antenna according to any one of claims 1 to 11.

13. The foldable electronic device according to claim 12, wherein: The electronic device includes a metal frame, and the metal frames located on both sides of the rotating shaft respectively form the first radiator and the second radiator.

14. The foldable electronic device according to claim 13, wherein: A top frame located at the top of the electronic device or a portion of a bottom frame located at the bottom of the electronic device forms the first radiator and the second radiator.

15. An electronic device, characterized in that: The invention comprises the antenna according to any one of claims 1 to 11.

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