Foldable Electronic Device and Its Antenna System

Abstract

The present application provides a foldable electronic device and an antenna system thereof. The antenna system includes a main antenna unit and a parasitic antenna unit. The main antenna unit is an antenna structure having the radiation characteristics of a current loop antenna, including a feeding point and a first radiating branch provided on a first body of the electronic device. The parasitic antenna unit includes a second radiating branch provided on a second body of the electronic device. In the folded state, the first radiating branch and the second radiating branch are at least partially overlapped, and the first radiating branch is used to perform magnetic field coupling with the second radiating branch to form current loop radiation on both the first and second radiating branches, and the current directions in the current loops respectively formed on the first and second radiating branches are the same. In this way, longitudinal currents in the same direction can be simultaneously excited on the folding floor of the electronic device, thereby achieving the purpose of reducing or eliminating the energy consumed in the folded state and improving the antenna efficiency, and effectively solving the problem of poor efficiency of the low-frequency antenna of the electronic device in the folded state.

Description

Technical Field

[0001] This application relates to the field of wireless communication technologies, and in particular, to a foldable electronic device and its antenna system. Background Art

[0002] After electronic devices such as mobile phones enter the intelligent era, in order to obtain a better user experience, the appearance form of electronic devices has changed from a large screen to a full screen and then to a foldable screen. Such foldable electronic devices bring new challenges to antenna design. Among them, when the electronic device is in a folded state and a gap is formed between the two folded main bodies, due to the presence of high-loss materials with high resistivity and poor conductivity in the gap, such as the indium tin oxide (ITO) layer included in the two folded screens, etc., these high-loss materials will absorb / consume the energy generated in the gap during the operation of the antenna, resulting in a significant decrease in the efficiency of the antenna in the mid-low frequency band compared to the unfolded state, and the decrease amplitude can reach 2 - 4 dB, thus leading to poor antenna performance. Therefore, how to improve the antenna performance in the folded state has become an important research topic in the field of antenna design. Summary of the Invention

[0003] This application provides a foldable electronic device and its antenna system. The antenna system includes a main antenna unit and a parasitic antenna unit capable of performing current loop radiation, which is used to improve the antenna performance of the electronic device in the folded state.

[0004] In a first aspect, this application provides an antenna system applied to a foldable electronic device. The foldable electronic device includes a first main body and a second main body that are connected to each other and can be relatively folded or unfolded. The antenna system includes a main antenna unit and a parasitic antenna unit. The main antenna unit includes a feeding point and a first radiation branch disposed on the first main body. Among them, the main antenna unit is an antenna structure with the radiation characteristics of a current loop antenna, and the feeding point is used to feed the first radiation branch. The parasitic antenna unit includes a second radiation branch disposed on the second main body. Wherein, when the electronic device is in a folded state, the first radiation branch and the second radiation branch are at least partially overlapped, and the first radiation branch is used to perform magnetic field coupling with the second radiation branch to form current loop radiation on both the first radiation branch and the second radiation branch, and the current direction in the current loop formed on the first radiation branch is the same as the current direction in the current loop formed on the second radiation branch.

[0005] The antenna system respectively sets opposite main antenna units and parasitic antenna units on two foldable bodies of the electronic device. Both the main antenna unit and the parasitic antenna unit adopt antenna structures with current loop radiation characteristics. In the folded state, magnetic field coupling between the main antenna unit and the parasitic antenna unit is utilized to form current loop radiation on both the first radiation branch and the second radiation branch, and to excite co-directional currents on the radiation branches of the two antenna units. According to the characteristics of current loop radiation, co-directional longitudinal currents can be simultaneously excited on two overlapping floors of the folded floor of the electronic device. In this way, on the one hand, the reverse transverse current generated by the gap mode in the folded state on the folded floor can be suppressed by the co-directional longitudinal currents on the two overlapping floors, so as to achieve the purpose of suppressing the excitation of the gap mode, reducing or eliminating the energy consumed in the folded state, and further improving the antenna efficiency in the folded state; on the other hand, the excitation effect of the longitudinal mode of the folded floor can be enhanced by the superposition effect of the co-directional longitudinal currents on the two overlapping floors, so as to achieve the purpose of further improving the antenna efficiency in the folded state, enabling the electronic device to obtain better antenna performance in the folded state, and effectively solving the problem of poor low-frequency antenna efficiency of the foldable electronic device in the folded state.

[0006] In one embodiment, the electronic device further includes a first reference ground corresponding to the first body and a second reference ground corresponding to the second body. When the electronic device is in the folded state, the main antenna unit is used to excite a closed current loop on the first radiation branch and the first reference ground, and is used to perform magnetic field coupling with the parasitic antenna unit, so as to excite a closed current loop on the second radiation branch and the second reference ground. Among them, the current direction on the first radiation branch is the same as the current direction on the second radiation branch, the current direction on the first radiation branch is opposite to the current direction on the first reference ground, the current direction on the second radiation branch is opposite to the current direction on the second reference ground, and the current direction on the first reference ground is the same as the current direction on the second reference ground. Since co-directional longitudinal currents are excited on the upper and lower reference grounds of the folded floor of the electronic device, the excitation effect of the longitudinal mode of the folded floor can be enhanced, achieving the purpose of improving the antenna efficiency. At the same time, the excitation of the gap mode of the folded floor can also be suppressed, reducing or eliminating the energy consumed in the folded state, so as to further achieve the purpose of improving the antenna performance in the folded state.

[0007] In one embodiment, the main antenna unit and the parasitic antenna unit are respectively any one of a current loop slot antenna, a current loop left-handed antenna, a current loop monopole antenna, a current loop dipole antenna, and a left-handed antenna. In this way, there are at least twenty-five implementation forms of the pairwise combination of the main antenna unit and the parasitic antenna unit. In specific applications, various different antenna combination forms can be flexibly adopted according to the actual antenna design requirements in the foldable electronic device to improve the antenna efficiency of the electronic device in the folded state and enable the electronic device to obtain good antenna performance in the folded state.

[0008] In one embodiment, the electronic device further includes a connecting portion provided between the first main body and the second main body, and the first main body and the second main body are connected through the connecting portion. The first radiation branch is provided at an edge of the first main body opposite to the connecting portion, and the second radiation branch is provided at an edge of the second main body opposite to the connecting portion.

[0009] In one embodiment, the first radiation branch is provided in the middle of the edge of the first main body opposite to the connecting portion, and the second radiation branch is provided in the middle of the edge of the second main body opposite to the connecting portion. In this way, by using the symmetry of the middle position, the antenna efficiency in the folded state can be further improved, and the electronic device can obtain better antenna performance in the folded state.

[0010] In one embodiment, the first radiation branch is coupled to the feeding point, and the first radiation branch is configured to generate a current under the excitation of the feeding point and perform radiation with the radiation characteristics of a current loop antenna. Alternatively, the main antenna unit further includes a feeding branch, the feeding point is provided on the feeding branch, the feeding branch is spaced from the first radiation branch, and the feeding branch couples energy to the first radiation branch through electric field / magnetic field coupling to excite the first radiation branch to perform current loop radiation. In specific applications, different feeding forms can be flexibly adopted according to the actual antenna design requirements in the foldable electronic device to realize the feeding of the main antenna unit.

[0011] In one embodiment, the main antenna unit and / or the parasitic antenna unit is a current loop slot antenna. The radiation branches of the current loop slot antenna include two radiators with opposite ends, and the opposite ends of the two radiators are coupled through a first capacitor. The other ends of the two radiators are respectively coupled to the corresponding reference ground, and a gap is formed between the two radiators and the reference ground; or,

[0012] The main antenna unit and / or the parasitic antenna unit is a current loop monopole antenna. The radiation branch of the current loop monopole antenna includes a radiator. One end of the radiator is coupled to the corresponding reference ground or the feeding point through a second capacitor, and the other end is coupled to the corresponding reference ground through a third capacitor; the length of the radiation branch of the current loop monopole antenna is less than one quarter of the operating wavelength of the current loop monopole antenna; or,

[0013] The main antenna unit and / or the parasitic antenna unit is a current loop dipole antenna. The radiation branch of the current loop dipole antenna includes two radiators with opposite ends. The opposite ends of the two radiators are coupled through a first capacitor. One end of one of the two radiators is coupled to the corresponding reference ground through a second capacitor, and the other end of the other radiator is coupled to the corresponding reference ground through a third capacitor; the length of the radiation branch of the current loop dipole antenna is less than one half of the operating wavelength of the current loop dipole antenna; or,

[0014] The main antenna unit and / or the parasitic antenna unit is a current loop left-handed antenna. The radiation branch of the current loop left-handed antenna includes two radiators with opposite ends. The opposite ends of the two radiators are coupled through a first capacitor. One end of one of the two radiators is coupled to the corresponding reference ground or the feeding point through a fourth capacitor, and the other end of the other radiator is coupled to the corresponding reference ground; or,

[0015] The main antenna unit and / or the parasitic antenna unit is a left-handed antenna. The radiation branch of the left-handed antenna includes a radiator. One end of the radiator is coupled to the corresponding reference ground or the feeding point through a fourth capacitor, and the other end is coupled to the corresponding reference ground.

[0016] In one embodiment, when the operating frequency band of the main antenna unit or the parasitic antenna unit is 450 MHz - 1 GHz, the capacitance value of the first capacitor ranges from [2 pF, 25 pF];

[0017] When the operating frequency band of the main antenna unit or the parasitic antenna unit is 1 GHz - 3 GHz, the capacitance value of the first capacitor ranges within [0.8 pF, 12 pF];

[0018] When the operating frequency band of the main antenna unit or the parasitic antenna unit is 3 GHz - 10 GHz, the capacitance value of the first capacitor ranges within [0.2 pF, 8 pF].

[0019] In one embodiment, when the operating frequency band of the main antenna unit or the parasitic antenna unit is 450 MHz - 1 GHz, the capacitance values of the second capacitor and the third capacitor range from [1.5 pF, 15 pF];

[0020] When the operating frequency band of the main antenna unit or the parasitic antenna unit is 1 GHz - 3 GHz, the capacitance values of the second capacitor and the third capacitor range from [0.5 pF, 15 pF];

[0021] When the operating frequency band of the main antenna unit or the parasitic antenna unit is 3 GHz - 10 GHz, the capacitance values of the first capacitor and the second capacitor range from [1.2 pF, 12 pF].

[0022] In a second aspect, the present application provides an antenna system for use in a foldable electronic device. The foldable electronic device includes a first body and a second body that are connected to each other and can be folded or unfolded relative to each other. The antenna system includes a main antenna unit and a parasitic antenna unit. The main antenna unit includes a feeding point and a first radiation branch disposed on the first body, wherein the feeding point is used to feed the first radiation branch. The parasitic antenna unit includes a second radiation branch disposed on the second body. When the electronic device is in a folded state, at least a part of the first radiation branch and the second radiation branch are overlapped, and the first radiation branch is used to perform magnetic field coupling with the second radiation branch. The main antenna unit is any one of a current loop slot antenna, a current loop left-handed antenna, a current loop monopole antenna, a current loop dipole antenna, and a left-handed antenna. The parasitic antenna unit is any one of a current loop slot antenna, a current loop left-handed antenna, a current loop monopole antenna, a current loop dipole antenna, and a left-handed antenna.

[0023] For the current loop slot antenna, the radiation branch of the current loop slot antenna includes two radiators with opposite ends, and the opposite ends of the two radiators are coupled by a first capacitor, and the other ends of the two radiators are respectively coupled to the reference ground, and a slot is formed between the two radiators and the reference ground;

[0024] For the current loop monopole antenna, the radiation branch of the current loop monopole antenna includes a radiator, one end of the radiator is coupled to the reference ground or the feeding point through a second capacitor, and the other end is coupled to the reference ground through a third capacitor; the length of the radiation branch of the current loop monopole antenna is less than one quarter of the operating wavelength of the current loop monopole antenna;

[0025] For the current-loop dipole antenna, the radiation branches of the current-loop dipole antenna include two radiators with opposite ends, the opposite ends of the two radiators are coupled by a first capacitor, one end of one of the two radiators is coupled to the reference ground through a second capacitor, and the other end of the other radiator is coupled to the reference ground through a third capacitor; the length of the radiation branches of the current-loop dipole antenna is less than half of the operating wavelength of the current-loop dipole antenna;

[0026] For the current-loop left-handed antenna, the radiation branches of the current-loop left-handed antenna include two radiators with opposite ends, the opposite ends of the two radiators are coupled by a first capacitor, one end of one of the two radiators is coupled to the reference ground or the feeding point through a fourth capacitor, and the other end of the other radiator is coupled to the reference ground;

[0027] For the left-handed antenna, the radiation branch of the left-handed antenna includes a radiator, one end of the radiator is coupled to the reference ground or the feeding point through a fourth capacitor, and the other end is coupled to the reference ground.

[0028] The antenna system respectively sets opposite main antenna units and parasitic antenna units on two foldable bodies of the electronic device, and uses the magnetic field coupling between the main antenna unit and the parasitic antenna unit in the folded state to solve the problem of poor low-frequency antenna efficiency of the foldable electronic device in the folded state. In the antenna system, there are at least twenty-five implementation forms of the pairwise combination of the main antenna unit and the parasitic antenna unit. In specific applications, various different antenna combination forms can be flexibly adopted according to the actual antenna design requirements in the foldable electronic device to improve the antenna efficiency of the electronic device in the folded state and enable the electronic device to obtain good antenna performance in the folded state.

[0029] In one embodiment, when the current-loop slot antenna is used as the main antenna unit,

[0030] the opposite ends of the two radiators are also respectively coupled to the feeding point; or

[0031] the current-loop slot antenna further includes a feeding branch, the feeding branch is arranged at an interval from the radiation branch of the current-loop slot antenna, and the feeding branch is arranged between the radiation branch of the current-loop slot antenna and the reference ground, the feeding point is arranged on the feeding branch, and the feeding branch is used for coupling and feeding the radiation branch of the current-loop slot antenna.

[0032] In one embodiment, when the current-loop left-handed antenna is used as the main antenna unit,

[0033] The other end of one of the radiators is coupled to the feeding point through a fourth capacitor; or

[0034] The current loop left-handed antenna further includes a feeding stub, the feeding stub is disposed at an interval from the radiation stub of the current loop left-handed antenna, and the feeding stub is disposed between the radiation stub of the current loop left-handed antenna and the reference ground, the feeding point is disposed on the feeding stub, and the feeding stub is used for coupling and feeding the radiation stub of the current loop left-handed antenna.

[0035] In one embodiment, when the current loop monopole antenna is used as the main antenna unit,

[0036] One end of the radiator is coupled to the feeding point through the second capacitor; or

[0037] The current loop monopole antenna further includes a feeding stub, the feeding stub is disposed at an interval from the radiation stub of the current loop monopole antenna, and the feeding stub is disposed between the radiation stub of the current loop monopole antenna and the reference ground, the feeding point is disposed on the feeding stub, and the feeding stub is used for coupling and feeding the radiation stub of the current loop monopole antenna.

[0038] In one embodiment, when the current loop dipole antenna is used as the main antenna unit,

[0039] The opposite ends of the two radiators are respectively coupled to the feeding point; or

[0040] The current loop dipole antenna further includes a feeding stub, the feeding stub is disposed at an interval from the radiation stub of the current loop dipole antenna, and the feeding stub is disposed between the radiation stub of the current loop dipole antenna and the reference ground, the feeding point is disposed on the feeding stub, and the feeding stub is used for coupling and feeding the radiation stub of the current loop dipole antenna.

[0041] In one embodiment, when the left-handed antenna is used as the main antenna unit, one end of the radiator is coupled to the feeding point through the fourth capacitor.

[0042] In one embodiment, when the operating frequency band of the main antenna unit or the parasitic antenna unit is 450 MHz - 1 GHz, the capacitance value of the first capacitor ranges from [2 pF, 25 pF];

[0043] When the operating frequency band of the main antenna unit or the parasitic antenna unit is 1 GHz - 3 GHz, the capacitance value of the first capacitor is within the range of [0.8 pF, 12 pF];

[0044] When the operating frequency band of the main antenna unit or the parasitic antenna unit is 3 GHz - 10 GHz, the capacitance value of the first capacitor ranges within [0.2 pF, 8 pF].

[0045] In one embodiment, when the operating frequency band of the main antenna unit or the parasitic antenna unit is 450 MHz - 1 GHz, the capacitance values of the second capacitor and the third capacitor range within [1.5 pF, 15 pF];

[0046] When the operating frequency band of the main antenna unit or the parasitic antenna unit is 1 GHz - 3 GHz, the capacitance values of the second capacitor and the third capacitor range within [0.5 pF, 15 pF];

[0047] When the operating frequency band of the main antenna unit or the parasitic antenna unit is 3 GHz - 10 GHz, the capacitance values of the second capacitor and the third capacitor range within [1.2 pF, 12 pF].

[0048] In one embodiment, the electronic device further includes a connecting portion disposed between the first main body and the second main body, and the first main body and the second main body are connected through the connecting portion;

[0049] The first radiation branch is disposed at an edge of the first main body opposite to the connecting portion, and the second radiation branch is disposed at an edge of the second main body opposite to the connecting portion.

[0050] In one embodiment, the first radiation branch is disposed at the middle of an edge of the first main body opposite to the connecting portion, and the second radiation branch is disposed at the middle of an edge of the second main body opposite to the connecting portion.

[0051] In a third aspect, the present application provides a foldable electronic device, including a first main body, a second main body, and the antenna system described in the first aspect or the second aspect above. The first main body and the second main body are connected to each other and can be relatively folded or unfolded. The main antenna unit included in the antenna system is disposed on the first main body, and the parasitic antenna unit included in the antenna system is disposed on the second main body.

[0052] In the foldable electronic device, by respectively arranging opposite main antenna units and parasitic antenna units on its two foldable bodies, and both the main antenna unit and the parasitic antenna unit adopt an antenna structure with a current loop radiation characteristic. In the folded state, using the magnetic field coupling between the main antenna unit and the parasitic antenna unit, current loop radiation is formed on both the first radiation branch and the second radiation branch, and co-directional currents are excited on the radiation branches of the two antenna units. According to the characteristics of current loop radiation, co-directional longitudinal currents can be simultaneously excited on the two overlapping floors of the folded floor of the electronic device. In this way, on the one hand, the reverse transverse current generated by the gap mode in the folded state on the folded floor can be suppressed by the co-directional longitudinal currents on the two overlapping floors, so as to achieve the purpose of suppressing the excitation of the gap mode, reducing or eliminating the energy consumed in the folded state, and further improving the antenna efficiency in the folded state. On the other hand, the excitation effect of the longitudinal mode of the folded floor can be enhanced by the superposition effect of the co-directional longitudinal currents on the two overlapping floors, so as to achieve the purpose of further improving the antenna efficiency in the folded state, enabling the electronic device to obtain better antenna performance in the folded state and effectively solving the problem of poor low-frequency antenna efficiency of the foldable electronic device in the folded state. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0054] Figure 1 FIG. is a schematic structural diagram of a foldable electronic device provided by an embodiment of the present application, where the electronic device is in an unfolded state.

[0055] Figure 2 is Figure 1 a schematic structural diagram of the electronic device shown when in a folded state.

[0056] Figure 3 is Figure 1 a schematic diagram of the functional modules of the electronic device shown, where the electronic device includes an antenna system.

[0057] Figure 4 is Figure 1 a schematic exploded view of the structure of the electronic device shown.

[0058] Figure 5 is Figure 2 a schematic equivalent structure diagram of the folded floor of the electronic device shown.

[0059] Figure 6(a) is Figure 5 a schematic diagram of the current distribution simulation when the longitudinal mode of the folding floor shown is excited.

[0060] Figure 6(b) is Figure 5 a schematic diagram of the current distribution simulation when the slot mode of the folding floor shown is excited.

[0061] Figure 7 a schematic diagram of the installation position of a common antenna in a conventional antenna scheme in the electronic device.

[0062] Figure 8 is a schematic diagram of the principle of the current distribution generated by exciting the Figure 5 intrinsic mode of the folding floor shown using a conventional antenna scheme.

[0063] Figure 9 is a schematic diagram of the principle of the current distribution generated by exciting the Figure 5 intrinsic mode of the folding floor shown using a conventional antenna scheme, where the display screen of the electronic device is folded in the slot between the folding floors.

[0064] Figure 10 is a schematic diagram of the principle of the current distribution generated by exciting the Figure 5 intrinsic mode of the folding floor shown using a conventional antenna scheme at the edge position of the folding floor.

[0065] Figure 11(a) is a schematic diagram of the current distribution simulation corresponding to the intrinsic mode of the folding floor of the electronic device excited during the operation of a common antenna in a conventional antenna scheme.

[0066] Figure 11(b) is a schematic diagram of the magnetic field distribution simulation corresponding to the intrinsic mode of the folding floor of the electronic device excited during the operation of a common antenna in a conventional antenna scheme.

[0067] Figure 12 is Figure 3 a schematic diagram of the functional modules of the antenna system shown, where the antenna system includes a main antenna unit and a parasitic antenna unit.

[0068] Figure 13 is Figure 12 a schematic diagram of the installation positions of the main antenna unit and the parasitic antenna unit in the electronic device shown.

[0069] Figure 14 a schematic diagram of an equivalent structure of the antenna scheme provided by an embodiment of the present application.

[0070] Figure 15 is Figure 14 a schematic diagram of the types of the main antenna unit and the parasitic antenna unit shown.

[0071] Figure 16(a) is Figure 14 a schematic diagram of the current loop formed on the main antenna element shown in the figure.

[0072] Figure 16(b) is Figure 14 a schematic diagram of the current loop formed on the parasitic antenna element shown in the figure.

[0073] Figure 17 It is for using Figure 14 the antenna scheme shown in the figure to excite Figure 5 a schematic diagram of the principle of the current distribution generated by the eigenmode of the folded floor shown in the figure.

[0074] Figure 18(a) is Figure 14 a simulation schematic diagram of the current distribution when the main antenna element and the parasitic antenna element resonate as shown in the figure.

[0075] Figure 18(b) is Figure 14 a simulation schematic diagram of the magnetic field distribution when the main antenna element and the parasitic antenna element resonate as shown in the figure.

[0076] Figure 18(c) is Figure 14 a simulation schematic diagram of the current distribution corresponding to the eigenmode of the folded floor of the electronic device excited by the main antenna element and the parasitic antenna element as shown in the figure.

[0077] Figure 19 It is an equivalent structure schematic diagram of a combined implementation form of the antenna scheme provided by the embodiment of the present application. Among them, the main antenna element is a current loop slot antenna, and the parasitic antenna element is a current loop left-handed antenna.

[0078] Figure 20(a) is Figure 19 a schematic diagram of a planar structure of a current loop slot antenna as shown in the figure.

[0079] Figure 20(b) is Figure 19 a schematic diagram of another planar structure of a current loop slot antenna as shown in the figure.

[0080] Figure 20(c) is Figure 19 a schematic diagram of a planar structure of a current loop left-handed antenna as shown in the figure.

[0081] Figure 21 It is an equivalent structure schematic diagram of another combined implementation form of the antenna structure provided by the embodiment of the present application. Among them, the main antenna element is a current loop left-handed antenna, and the parasitic antenna element is a current loop monopole antenna.

[0082] Figure 22(a) is Figure 21 a schematic diagram of a planar structure of a current loop left-handed antenna as shown in the figure.

[0083] Figure 22(b) is Figure 21Another schematic diagram of the planar structure of the current-loop left-handed antenna shown.

[0084] Figure 22(c) is Figure 21 A schematic diagram of the planar structure of the current-loop monopole antenna shown.

[0085] Figure 23 An equivalent structure schematic diagram of another combined implementation form of the antenna structure provided by the embodiment of the present application, wherein the main antenna unit is a current-loop monopole antenna, and the parasitic antenna unit is a left-handed antenna.

[0086] Figure 24(a) is Figure 23 A schematic diagram of the planar structure of the current-loop monopole antenna shown.

[0087] Figure 24(b) is Figure 23 Another schematic diagram of the planar structure of the current-loop monopole antenna shown.

[0088] Figure 24(c) is Figure 23 A schematic diagram of the planar structure of the left-handed antenna shown.

[0089] Figure 25 An equivalent structure schematic diagram of another combined implementation form of the antenna structure provided by the embodiment of the present application, wherein the main antenna unit is a current-loop dipole antenna, and the parasitic antenna unit is a current-loop slot antenna.

[0090] Figure 26(a) is Figure 25 A schematic diagram of the planar structure of the current-loop dipole antenna shown.

[0091] Figure 26(b) is Figure 25 Another schematic diagram of the planar structure of the current-loop dipole antenna shown.

[0092] Figure 26(c) is Figure 25 A schematic diagram of the planar structure of the current-loop slot antenna shown.

[0093] Figure 27 An equivalent structure schematic diagram of another combined implementation form of the antenna structure provided by the embodiment of the present application, wherein the main antenna unit is a left-handed antenna, and the parasitic antenna unit is a current-loop dipole antenna.

[0094] Figure 28(a) is Figure 27 A schematic diagram of the planar structure of the left-handed antenna shown.

[0095] Figure 28(b) is Figure 27 A schematic diagram of the planar structure of the current-loop dipole antenna shown.

[0096] Figure 29Schematic diagram of an equivalent structure of another combined implementation form of the antenna structure provided by the embodiment of the present application, where both the main antenna unit and the parasitic antenna unit are left-handed antennas.

[0097] Figure 30 For Figures 7 - 10 Schematic diagram of the simulation efficiency curve of the conventional antenna scheme shown in Figure 14 and the schematic diagram of the simulation efficiency curve of an antenna scheme provided by the embodiment shown in

[0098] Figure 31 For Figures 7 - 10 Schematic diagram of the simulation efficiency curve of the conventional antenna scheme shown in Figure 29 and the schematic diagram of the simulation efficiency curve of another antenna scheme provided by the embodiment shown in

[0099] Description of main component symbols

[0100] Electronic device 100

[0101] First main body 11

[0102] Second main body 12

[0103] Connection part 13

[0104] Display screen 14

[0105] First display screen 141

[0106] Second display screen 142

[0107] Antenna system 200

[0108] Antenna 20

[0109] Main antenna unit 21

[0110] First radiation branch 211

[0111] Feeding branch 212

[0112] First feeding part L01

[0113] Second feeding part L02

[0114] Parasitic antenna unit 22

[0115] Second radiation branch 221

[0116] Radiators L1, L2, L3, L4, L11, L12, L21, L22, L31, L41, L51, L52

[0117] Feeding point P0

[0118] First capacitor C1

[0119] Second capacitor C2

[0120] Third capacitor C3

[0121] Fourth capacitor C0

[0122] Gap G0

[0123] Other antenna unit 23

[0124] RF module 24

[0125] Processor 31

[0126] Memory 32

[0127] Power supply module 33

[0128] Other input / output device 34

[0129] Housing 40

[0130] Middle frame 41

[0131] First middle frame 411

[0132] Second middle frame 412

[0133] Rear cover 42

[0134] First rear cover 421

[0135] Second rear cover 422

[0136] Internal components 50

[0137] First circuit board assembly 511

[0138] First battery unit 512

[0139] Second circuit board assembly 521

[0140] Second battery unit 522

[0141] Folding floor 60

[0142] First reference ground 61

[0143] Second reference ground 62

[0144] Edge area A

[0145] Ordinary antenna a

[0146] First edge area B1

[0147] Second edge area B2

[0148] The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. Specific Embodiments

[0149] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Among them, the drawings are only for illustrative purposes and show only schematic diagrams, and should not be construed as limiting the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0150] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by those skilled in the art. The terms used in the present application in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0151] The present application provides a foldable electronic device, which includes a first body and a second body that can be relatively folded or unfolded, and an antenna system. The antenna system includes a main antenna unit and a parasitic antenna unit respectively disposed opposite to each other in the edge regions of the two foldable bodies of the electronic device. For the longitudinal mode and the slot mode included in the eigenmode of the foldable floor of the electronic device, both the main antenna unit and the parasitic antenna unit adopt an antenna structure with the radiation characteristics of a current loop antenna. In the folded state, by using the magnetic field coupling between the main antenna unit and the parasitic antenna unit, current loop radiation is formed on the radiation branches of both antenna units, and co-directional currents are excited on the radiation branches of both antenna units. According to the characteristics of the current loop radiation, co-directional longitudinal currents can be simultaneously excited on the two overlapping floors of the foldable floor of the electronic device. In this way, on the one hand, the reverse transverse current generated by the slot mode in the folded state on the foldable floor can be suppressed by the co-directional longitudinal currents on the two overlapping floors, so as to achieve the purpose of suppressing the excitation of the slot mode, reducing or eliminating the energy consumed in the folded state, and further improving the antenna efficiency in the folded state; on the other hand, the excitation effect of the longitudinal mode of the foldable floor can be enhanced by the superposition effect of the co-directional longitudinal currents on the two overlapping floors, so as to achieve the purpose of further improving the antenna efficiency in the folded state, enabling the electronic device to obtain better antenna performance in the folded state, and effectively solving the problem of poor low-frequency antenna efficiency of the foldable electronic device 100 in the folded state.

[0152] Figures 1 - 2 Exemplarily shown is a schematic structural diagram of a foldable electronic device 100 provided by an embodiment of the present application. Among them, the electronic device 100 includes, but is not limited to, electronic devices such as mobile phones, tablet computers, and wearable devices.

[0153] As shown Figures 1 - 2 in FIG. 1, the electronic device 100 includes a first body 11 and a second body 12 that are interconnected. In this embodiment, the electronic device 100 further includes a connecting portion 13 disposed between the first body 11 and the second body 12. The first body 11 and the second body 12 are connected through the connecting portion 13, and the two can be relatively folded or unfolded through the connecting portion 13, so that the electronic device 100 can have two usage modes. Among them, Figure 1 FIG. 2 shows a schematic structural diagram of the electronic device 100 when it is in the unfolded state usage mode, Figure 2 and FIG. 3 shows a schematic structural diagram of the electronic device 100 when it is in the folded state usage mode. As shown Figure 2 in FIG. 4, when the electronic device 100 is in the folded state, a gap G0 is formed between the first body 11 and the second body 12.

[0154] The electronic device 100 may further be provided with a connection structure (not shown in the figure), such as a rotating shaft or a hinge structure, etc., on the connecting portion 13 between the first body 11 and the second body 12. The first body 11 and the second body 12 are connected through the connection structure, and the two can rotate through the connection structure, so that the two can be switched between the relatively folded state and the relatively unfolded state.

[0155] In this embodiment, the electronic device 100 further includes a display screen 14 disposed on the first body 11 and the second body 12. The display screen 14 is used to display visual output to the user. The visual output may include graphics, text, icons, videos, etc. The display screen 14 may include a first display screen 141 and a second display screen 142. Among them, the first display screen 141 may be disposed on the first body 11, and the second display screen 142 may be disposed on the second body 12. Optionally, one of the first display screen 141 and the second display screen 142 may be set as the main screen, and the other display screen may be set as the secondary screen.

[0156] In one embodiment, the first display screen 141 and the second display screen 142 can be coupled to each other, so that the display screen 14 can be continuously disposed on the same side of the first body 11 and the second body 12. In this way, when the electronic device 100 is in a fully unfolded state, the first display screen 141 and the second display screen 142 can form a complete plane, so that the electronic device 100 has a continuous large-area display screen in the unfolded state, thereby realizing the function of large-screen display and meeting the user's usage requirement for large-screen display. When the electronic device 100 is in a folded state, it has a small-area display screen, which can meet the user's usage requirement for easy carrying.

[0157] Wherein, the display screen 14 can be a flexible screen. When the electronic device 100 is in a folded state, the display screen 14 can be hidden inside the electronic device 100 or exposed outside the electronic device 100. This application does not limit the type of the display screen 14 and the presentation manner of the display screen 14 when the electronic device 100 is in a folded state.

[0158] Figure 3 Exemplarily, a schematic diagram of the functional modules of the electronic device 100 is shown. As Figure 3 shown, in addition to the display screen 14, the electronic device 100 may further include a processor 31, a memory 32, a power module 33, and other input / output devices 34.

[0159] Wherein, the processor 31 serves as the logical operation and control center of the electronic device 100, and is mainly responsible for functions such as data acquisition, data conversion, data processing, logical operation, communication, and execution of drive output. The processor 31 may include a plurality of input / output ports, and the processor 31 can communicate and interact with other functional modules or external devices through the plurality of input / output ports, so as to realize functions such as driving and controlling the electronic device 100.

[0160] The memory 32 can be accessed by the processor 31 or a peripheral interface (not shown in the figure) etc. to realize storage or calling of data. The memory 32 may include a high-speed random access memory, and may further include a non-volatile memory, such as one or more disk storage devices, flash memory devices, or other volatile solid-state storage devices.

[0161] The power module 33 is used to supply power to other functional modules of the electronic device 100 and perform power management, so that other functional modules of the electronic device 100 can work normally.

[0162] The other input / output device 34 may include devices for implementing functions supported by the electronic device 100, such as speakers, touch pads, cameras, function buttons, I / O ports, etc., so as to enable interaction between the electronic device 100 and the user.

[0163] In this embodiment, the electronic device 100 further has a wireless communication function. Correspondingly, the electronic device 100 further includes an antenna system 200. The antenna system 200 at least includes an antenna 20 and a radio frequency module 24. Among them, the antenna 20 can be coupled to the radio frequency module 24 through a transmission element (not shown in the figure), such as a coaxial cable or a microstrip line, to achieve the transmission of wireless signals, thereby establishing communication between the electronic device 100 and other network devices. In the electronic device 100, in order to meet the user's usage requirements for various wireless communication technologies, the antenna 20 usually includes a plurality of antenna units. Each antenna unit can be used to cover a single or multiple communication frequency bands, and different antenna units can also be multiplexed to improve the utilization rate of the antenna. The plurality of antenna units can be distributed on the first body 11 and / or the second body 12, and the antenna form can be diverse. For example, it can be in the form of a monopole antenna, a dipole antenna, an inverted F-shaped antenna (IFA), etc.

[0164] It can be understood that the electronic device 100 may further include a circuit board assembly (not shown in the figure) disposed inside the first body 11 and / or the second body 12. The circuit board assembly is used to dispose electronic components included in the electronic device 100, such as the processor 31, the memory 32, the radio frequency module 24, etc. Among them, the circuit board assembly can be a flexible circuit board assembly or a rigid-flex circuit board assembly.

[0165] Figure 4 An exemplary structural decomposition diagram of the electronic device 100 is shown. As Figure 4 shown, the electronic device 100 at least includes a display screen 14, a housing 40, and internal components 50 housed in a housing cavity surrounded by the display screen 14 and the housing 40.

[0166] Specifically, the housing 40 includes a middle frame 41 and a rear cover 42. Among them, the middle frame 41 is at least connected to the edge area of the rear cover 42. The middle frame 41 can be partially or entirely formed of a conductive structure (such as metal), or the middle frame 41 can be partially or entirely formed of a dielectric structure (such as plastic). Among them, the middle frame 41 includes a first middle frame 411 corresponding to the first body 11 and a second middle frame 412 corresponding to the second body 12, and the first middle frame 411 and the second middle frame 412 are connected to each other.

[0167] The rear cover 42 can be formed of a conductive structure (such as metal) or a dielectric structure (such as glass). Among them, the rear cover 42 includes a first rear cover 421 corresponding to the first main body 11 and a second rear cover 422 corresponding to the second main body 12. The first rear cover 421 and the second rear cover 422 can be connected through the connecting portion 13.

[0168] In this embodiment, when the electronic device 100 is in a folded state, the first middle frame 411 and the second middle frame 412 are overlapped, and the first rear cover 421 and the second rear cover 422 are overlapped. The antenna 20 can be disposed on the middle frame 41 and / or the rear cover.

[0169] The internal components 50 accommodated in the accommodation cavity include, but are not limited to, a first circuit board assembly 511 and a first battery unit 512 corresponding to the first main body 11, and a second circuit board assembly 521 and a second battery unit 522 corresponding to the second main body 12. Among them, the first circuit board assembly 511 is used to arrange the electronic components included in the first main body 11, the second circuit board assembly 521 is used to arrange the electronic components included in the second main body 12, and the first battery unit 512 and the second battery unit 522 are used to supply power to the electronic components arranged on the first main body 11 and / or the second main body 12. In another embodiment, the electronic device 100 may also include one battery unit or more than two battery units.

[0170] In this embodiment, several metal components disposed on the first main body 11, such as some or all of the metal structures on the first middle frame 411, some or all of the metal structures on the first rear cover 421, and several components with metal conductive characteristics included in the first circuit board assembly 511 and the first battery unit 512, etc., can be coupled to form a first reference ground 61 corresponding to the first main body 11. Similarly, several metal components disposed on the second main body 12, such as some or all of the metal structures on the second middle frame 412, some or all of the metal structures on the second rear cover 422, and several components with metal conductive characteristics included in the second circuit board assembly 521 and the second battery unit 522, etc., can be coupled to form a second reference ground 62 corresponding to the second main body 12.

[0171] It should be noted that the first reference ground 61 and the second reference ground 62 involved in the present application are not a complete metal floor, but a combination of several coupled metal parts. For the convenience of illustration and understanding, the first reference ground 61 and the second reference ground 62 are represented by a complete block-shaped equivalent structure with a certain thickness, wherein the first reference ground 61 and the second reference ground 62 can be coupled to each other.

[0172] Understandably, Figure 3 and Figure 4 The electronic device 100 shown is only an example of the electronic device, and the electronic device 100 may have more than Figure 3 and Figure 4 More or fewer components may be shown, two or more components may be combined, or different component configurations may be provided.

[0173] Figure 5 Shows an equivalent structural schematic diagram of the first reference ground 61 and the second reference ground 62. It can be understood that when the electronic device 100 is in the unfolded state, the electronic device 100 has a large-area single floor (not shown) composed of the first reference ground 61 and the second reference ground 62 that are continuously distributed. When the electronic device 100 is in the folded state, the electronic device 100 has a small-area folding floor 60 composed of the first reference ground 61 and the second reference ground 62 that are overlapped.

[0174] During the use of the electronic device 100, the inventor found that the antenna efficiency of the electronic device 100 in the two basic states of unfolding and folding is very different: compared with the antenna efficiency in the unfolded state, the antenna efficiency of the electronic device 100 in the folded state is significantly worse. This difference is more obvious in the low-frequency band, and the low-frequency antenna efficiency in the folded state is about 2-4dB lower than that in the unfolded state. In order to analyze the reasons for the decrease in antenna efficiency in the folded state and to improve the antenna efficiency corresponding to the folded state, the inventor conducted a lot of research and analysis.

[0175] ​​Among them, through simulation experiments to analyze the intrinsic mode of the floor of the electronic device 100, it is known that when the electronic device 100 is in the unfolded state, the intrinsic mode of the large-area single floor of the electronic device 100 in the low-frequency band shows a longitudinal mode. When the electronic device 100 is in the folded state, the intrinsic mode of the small-area folded floor 60 of the electronic device 100 in the low-frequency band shows a longitudinal mode and a slot mode. It should be noted that the intrinsic mode refers to the inherent resonance mode of the metal body without any excitation, which has nothing to do with the antenna. Moreover, whether the intrinsic mode of the metal body can be excited and the excitation effect of the intrinsic mode depend on the antenna design on the metal body.

[0176] Figures 6(a) - 6(b) Fig. 6 shows a simulation schematic diagram of the current distribution when two intrinsic modes of the folded floor 60 of the electronic device 100 in the low-frequency band are excited. Among them, Fig. 6(a) shows a simulation schematic diagram of the current distribution when the longitudinal mode of the folded floor 60 is excited. The current on the folded floor 60 is distributed longitudinally along the outer surfaces of the two metal body floors, that is, the first reference ground 61 and the second reference ground 62, forming a "longitudinal current". Fig. 6(b) shows a simulation schematic diagram of the current distribution when the slot mode of the folded floor 60 is excited. The current on the folded floor 60 is distributed transversely along the inner surfaces of the two floors, forming a "transverse current", and the directions of the transverse currents on the two floors are opposite.

[0177] Based on Figures 6(a) - 6(b) the simulation results shown above, the following uses a conventional antenna scheme to excite the intrinsic mode of the folded floor 60 of the electronic device 100 and analyzes the principles of the electric field and current generated on the folded floor 60.

[0178] A conventional antenna scheme is to set a common antenna a at the edge of the main body of the electronic device 100. For example, Figures 7 - 8 as shown, the electronic device 100 sets a common IFA antenna in the edge area A opposite to the connecting portion 13 of the first main body 11. In this way, the common antenna a is adjacent to the edge of the first reference ground 61, or the common antenna a is located at the edge of the first reference ground 61, and the radiation branches of the common antenna a are arranged longitudinally along the first reference ground 61.

[0179] As Figure 8As shown, when the electronic device 100 is in the folded state, the upper and lower metal floor plates of the folding floor 60, namely the first reference ground 61 and the second reference ground 62, are overlapped, which is equivalent to forming a parallel-plate capacitor. When the ordinary antenna a is excited, an electric field will be coupled in the gap G0 between the upper and lower floor plates. The direction of the electric field is from one floor plate to the other. Among them, the electric field strength at the position close to the ordinary antenna a is higher than that close to the connecting portion 13, and transverse currents with opposite directions will be induced on the inner surfaces of the upper and lower floor plates close to the gap G0.

[0180] It can also be understood here that when the ordinary antenna a is excited, a current will be induced on the upper floor plate, making the upper floor plate carry positive or negative charges. When the upper and lower floor plates of the folding floor 60 approach each other, at a certain moment, if the upper floor plate carries positive charges, negative charges will be induced on the lower floor plate, and a voltage difference will be formed between the two overlapping floor plates. Therefore, the electric field will be generated in the gap G0 between the two. The upper and lower floor plates are coupled through the connecting portion 13, and currents are induced on the inner surfaces of the upper and lower floor plates close to the gap G0, and the current distribution directions on the upper and lower floor plates are opposite.

[0181] Since the upper and lower floor plates of the folding floor 60 have a certain thickness, and this thickness is generally much larger than the distance of the gap G0, therefore, the current induced in the gap G0 mainly adheres to the inner surfaces of the upper and lower floor plates close to the gap G0. It can also be understood here that due to the existence of the parallel-plate capacitor, the current induced in the gap G0 mainly adheres to the inner surfaces of the upper and lower floor plates close to the gap G0, that is, the "transverse current" or "gap current" of the gap mode is formed.

[0182] In addition, the currents of the longitudinal mode excited on the upper and lower floor plates mainly adhere to the outer surfaces of the upper and lower floor plates and are distributed longitudinally along the two floor plates, that is, the "longitudinal current" of the longitudinal mode is formed. Among them, the current and electric field distributions of the longitudinal mode of the folding floor 60 are similar to the current and electric field distributions of the longitudinal mode of the single floor in the unfolded state.

[0183] Based on the above analysis of the simulation results of the current distribution of the eigenmode of the floor of the foldable electronic device 100 and the principle of current generation, it can be seen that compared with the single floor in the unfolded state, the eigenmode of the folding floor 60 has an additional gap mode. Thus, for the foldable electronic device 100, the reason why the antenna efficiency in the folded state is significantly lower than that in the unfolded state should be related to the excitation of the gap mode of the folding floor 60.

[0184] Through research, it is found that in the folded state, when the slot mode is excited, the energy generated in the slot G0 will be consumed / absorbed by the high-loss material located in the slot G0, resulting in a significant decrease in the antenna efficiency in this slot mode and affecting the antenna radiation effect.

[0185] Specifically, in the folded state, there is a high-loss material with a relatively high resistivity and a poor conductivity in the slot G0. For example, in the folded state, if the display screen 14 is hidden inside the electronic device 100, the ITO layer and the like included in the display screen 14 will provide the high-loss material in the slot G0. If the display screen 14 is exposed outside the electronic device 100 and the glass back cover of the electronic device 100 is hidden inside the electronic device 100, the glass layer included in the glass back cover will also provide the high-loss material in the slot G0. As Figure 9 shown, in this application, taking the display screen 14 being hidden inside the electronic device 100 as an example, the reason for the deterioration of the antenna efficiency of the folded electronic device 100 is analyzed.

[0186] As described above, when the ordinary antenna a is excited, an electric field will be coupled in the slot G0 between the upper and lower ground planes, and transverse currents with opposite directions will be induced on the inner surfaces of the upper and lower ground planes close to the slot G0. Since the display screen 14 exists in the slot G0 and is attached to the inner surfaces of the upper and lower ground planes, thus, the induced currents on the inner surfaces of the upper and lower ground planes will encounter the high-loss material included in the display screen 14, that is, the dielectric with resistivity, and then will be absorbed or consumed by the high-loss material. Here, it can also be understood that the high-loss material is added to the slot G0, and in the closed space of the slot G0, the electric field will pass through the high-loss material and the electric field energy will be absorbed or consumed by the high-loss material.

[0187] According to the above analysis, it can be known that when the eigenmode of the folded ground plane 60 is excited, if the current of the excited slot mode is more, the energy consumed by the slot mode will be more, resulting in the antenna efficiency in the folded state being significantly lower than that in the unfolded state.

[0188] In addition, as described above, when the ordinary antenna a is excited, the longitudinal currents of the longitudinal mode excited on the upper and lower ground planes mainly tend to attach to the outer surfaces of the upper and lower ground planes. Therefore, this longitudinal current will not be absorbed by the high-loss material in the slot G0. It can be seen that the excitation of the longitudinal mode is not the reason for the deterioration of the antenna efficiency in the folded state, and the longitudinal mode can be utilized for antenna radiation.

[0189] Since the longitudinal mode generates longitudinal currents on both the first reference ground 61 and the second reference ground 62 of the folding floor 60, and the slot mode generates reverse transverse currents on the first reference ground 61 and the second reference ground 62 of the folding floor 60 respectively, as Figure 9 shown, the direction of the longitudinal current generated by the longitudinal mode on the folding floor 60 is orthogonal to the direction of the transverse current generated by the slot mode on the folding floor 60. It can be seen that the longitudinal mode and the slot mode are incompatible. Thus, when exciting the eigenmode of the folding floor 60, the more slot modes are excited at the same time, the fewer longitudinal modes there will be, which will lead to a deterioration in the antenna efficiency in the folded state.

[0190] From this, it can be known that in order to improve the antenna efficiency in the folded state, one of the key points is to suppress the excitation of the slot mode of the folding floor 60 and reduce or eliminate the energy consumed in the folded state.

[0191] Please refer to Figure 10 , for the above conventional antenna scheme, since the ordinary antenna a is only arranged at the edge of one of the main bodies (for example, the first main body 11) of the electronic device 100, when the ordinary antenna a excites a current I 1 , as described above, an electric field will be coupled in the slot G0 between the upper and lower floors, and the direction of the electric field is from one floor to the other floor. And at the edge positions of the upper and lower floors opposite to the connecting portion 13, as Figure 10 shown, the current I 1 excited on the ordinary antenna a is longitudinally distributed along the first reference ground 61. The ordinary antenna a is coupled to the first reference ground 61 through the electric field, and a reverse current I 2 longitudinally distributed along the first reference ground 61 will be induced on the first reference ground 61 near the ordinary antenna a. Since there is no resonant unit arranged on the other main body (for example, the second main body 12), the ordinary antenna a is coupled to the second reference ground 62 through the electric field, and a longitudinally distributed reverse current I 3 is induced near the position of the second reference ground 62 corresponding to the ordinary antenna a.

[0192] From Figure 10It can be seen that the longitudinal modes of the first reference ground 61 and the second reference ground 62 of the folding floor 60 can both generate longitudinal currents in the same direction. However, if, as in the conventional antenna scheme, the ordinary antenna a is only provided on one of the main bodies, for example, the first main body 11, to excite the longitudinal current of the first reference ground 61, in the folded state, for the second reference ground 62, since there is no resonant unit provided on the second reference ground 62, the second reference ground 62 completely participates in the coupling passively. Thus, the longitudinal mode of the second reference ground 62 is excited by the current coupled from the ordinary antenna a to the second reference ground 62, and the excitation effect of the longitudinal mode of the second reference ground 62 is not significant. Therefore, the longitudinal current excited on the second reference ground 62 is weak.

[0193] From this, it can be known that in order to improve the antenna efficiency in the folded state, another key point is to enhance the excitation of the longitudinal currents in the same direction on the upper and lower reference grounds of the folding floor 60.

[0194] Based on the above analysis, the inventor also performs simulation verification on the current distribution and magnetic field distribution corresponding to the eigenmode of the folding floor 60 of the electronic device 100 adopting the above conventional antenna scheme. Among them, Fig. 11(a) shows a schematic diagram of the simulation of the current distribution corresponding to the eigenmode of the folding floor 60 excited by the ordinary antenna a during operation. As shown in Fig. 11(a), when the ordinary antenna a is operating, on the folding floor 60, in addition to the longitudinal mode, the slot mode is also excited. And the ordinary antenna a can only excite longitudinal currents near the position where the ordinary antenna a is located and on the connecting portion 13, but the current excited on the overlapping floor near the connecting portion 13 is still a transverse current.

[0195] Fig. 11(b) shows a schematic diagram of the simulation of the magnetic field distribution corresponding to the eigenmode of the folding floor 60 excited by the ordinary antenna a during operation. As shown in Fig. 11(b), when the ordinary antenna a is operating, the magnetic fields distributed in the space near the outside of the position of the ordinary antenna a (i.e., the right edge of the first reference ground 61 shown in Fig. 11(b)) and in the space near the outside of the connecting portion 13 are both parallel to the end face of the first reference ground 61 (i.e., the right end of the first reference ground 61 shown in Fig. 11(b)). Combining with Ampere's law (right-hand screw rule), it can be known that the currents at the position where the ordinary antenna a is located and on the connecting portion 13 are both distributed longitudinally along the folding floor 60. And in the slot G0, the magnetic field distribution near the connecting portion 13 on the left side of the folding floor 60 is normal to the screen (i.e., the magnetic field direction is perpendicular outward, pointing to the reader), indicating that the current here is distributed transversely along the folding floor 60, that is, the current distribution here is still in the slot mode.

[0196] Combining the current distribution simulation results shown in Fig. 11(a) and the magnetic field distribution simulation results shown in Fig. 11(b), it can be seen that the effect of the ordinary antenna a exciting the longitudinal mode of the folded floor 60 is poor, and it is difficult to suppress the excitation of the slot mode of the folded floor 60. Since the electronic device 100 adopts such a conventional antenna scheme, more slot modes are excited, resulting in a significant decrease in the antenna efficiency in the folded state.

[0197] Through the inventor's efforts in research and analysis and a large number of experimental data simulation results, it is found that when a main antenna unit and a parasitic antenna unit are respectively arranged at the edges of the two main bodies of the electronic device 100, and both the main antenna unit and the parasitic antenna unit adopt an antenna structure with the radiation characteristics of a current loop antenna, magnetic field coupling is carried out between the main antenna unit and the parasitic antenna unit, current loop radiation is respectively formed on the radiation branches of the two antenna units, and co-directional currents are respectively excited on the radiation branches of the two antenna units. In this way, co-directional longitudinal currents can be excited on the upper and lower reference grounds of the folded floor 60, so as to enhance the excitation effect of the longitudinal mode, and at the same time, the excitation of the slot mode can be suppressed, the energy consumed in the folded state can be reduced or eliminated, and the purpose of improving the antenna performance in the folded state can be achieved. Among them, the radiation characteristics of the current loop antenna mean that when the antenna unit is working, there is a uniform magnetic field near the radiation branch of the antenna unit.

[0198] Specifically, in this embodiment, as Figure 12 shown, the antenna 20 of the antenna system 200 includes a main antenna unit 21, a parasitic antenna unit 22, and other antenna units 23. As Figure 13 shown, the main antenna unit 21 is arranged on the first edge area B1 of the first main body 11, and the parasitic antenna unit 22 is arranged on the second edge area B2 of the second main body 12. Among them, the first edge area B1 includes the part on the first middle frame 411 or the part of the first rear cover 421 close to the first middle frame 411, and the second edge area B2 includes the part on the second middle frame 412 or the part of the second rear cover 422 close to the second middle frame 412.

[0199] Figure 14 An exemplary equivalent structure diagram of the main antenna unit 21, the parasitic antenna unit 22, the first reference ground 61 of the first main body 11, and the second reference ground 62 of the second main body 12 is shown. Please refer to Figure 13 and Figure 14, the main antenna unit 21 includes a first radiation branch 211 disposed on the first edge region B1, and the parasitic antenna unit 22 includes a second radiation branch 221 disposed on the second edge region B2. When the electronic device 100 is in a fully folded state, the first radiation branch 211 and the second radiation branch 221 are at least partially overlapped.

[0200] In this embodiment, the first edge region B1 is disposed on the edge where the first main body 11 and the connecting portion 13 are oppositely arranged, and the second edge region B2 is disposed on the edge where the second main body 12 and the connecting portion 13 are oppositely arranged. The other antenna unit 23 may be disposed on the middle frame 41 and / or the rear cover, and the present application does not specifically limit the form, quantity, position, etc. of the other antenna unit 23.

[0201] In this embodiment, both the main antenna unit 21 and the parasitic antenna unit 22 are antenna structures having the radiation characteristics of a current loop antenna, and the first radiation branch 211 and the second radiation branch 221 are radiators capable of performing current loop radiation. Among them, the first radiation branch 211 may include one or more radiators. For example Figure 14 as shown, the first radiation branch 211 includes two radiators L1 and L2. Similarly, the second radiation branch 221 may also include one or more radiators. For example Figure 14 as shown, the second radiation branch 221 includes two radiators L3 and L4. The number of radiators of the first radiation branch 211 is determined by the antenna form of the main antenna unit 21. Similarly, the number of radiators of the second radiation branch 221 is determined by the antenna form of the parasitic antenna unit 22. The embodiments of the present application do not specifically limit the number of radiators of the two radiation branches.

[0202] In this embodiment, the main antenna unit 21 and the parasitic antenna unit 22 may include various different specific implementation forms. For example, as Figure 15As shown, the main antenna unit 21 and the parasitic antenna unit 22 can be any one of a current loop slot antenna, a current loop left-handed antenna, a current loop monopole antenna (such as a current loop ILA antenna), a current loop dipole antenna, and a left-handed antenna respectively. Among them, the structure of the left-handed antenna can refer to the introductions in CN201380008276.8 and CN201410109571.9, which will not be elaborated here. The current loop slot antenna is an antenna structure based on the slot antenna, the current loop left-handed antenna is an antenna structure based on the left-handed antenna, the current loop monopole antenna is an antenna structure based on the monopole antenna, and the current loop dipole antenna is an antenna structure based on the dipole antenna. In the embodiments of the present application, the current loop monopole antenna, the current loop dipole antenna, the current loop slot antenna, and the current loop left-handed antenna are collectively referred to as the current loop antenna. As a new form of antenna, the current loop antenna adopts a structure similar to that of a typical antenna and can generate a uniformly distributed magnetic field around its radiation branches, thereby generating resonance to cover the working frequency band. The various structures and working principles of the current loop antenna can refer to the introduction in CN202110961752.4, which will not be elaborated here.

[0203] In this embodiment, the first radiation branch 211 is used to perform magnetic field coupling with the second radiation branch 221, so as to form current loop radiation on both the first radiation branch 211 and the second radiation branch 221, and the current direction in the current loop formed on the first radiation branch 211 is the same as the current direction in the current loop formed on the second radiation branch 221.

[0204] Specifically, in this embodiment, the main antenna unit 21 further includes a feeding point P0, and the feeding point P0 is used to feed the first radiation branch 211, so as to generate current on the two radiators L1 and L2 of the first radiation branch 211, forming radiation with the radiation characteristics of a current loop antenna.

[0205] The parasitic antenna unit 22 is a passive antenna structure containing a resonant structure. The first radiation branch 211 is also used to perform magnetic field coupling with the second radiation branch 221, so as to realize the excitation of the current on the second radiation branch 221 in the form of magnetic field coupling, enabling the second radiation branch 221 to perform radiation with the radiation characteristics of a current loop antenna. Specifically, the second radiation branch 221 is fed by magnetic field coupling with the first radiation branch 211, and obtains magnetic excitation from the two radiators L11 and L12, so as to generate current on the two radiators L3 and L4, forming radiation with the radiation characteristics of a current loop antenna.

[0206] When the electronic device 100 is in the folded state and the main antenna unit 21 is operating, a current is generated on the first radiation branch 211 to perform current loop radiation. FIG. 16(a) shows a schematic diagram of the current loop formed on the main antenna unit 21. As shown in FIG. 16(a), the current excited on the first radiation branch 211 is opposite in direction to the current excited on the portion of the first reference ground 61 close to the first radiation branch 211. Therefore, the current on the first radiation branch 211 and the current generated on the portion of the first reference ground 61 close to the first radiation branch 211 form a closed first radiation current loop, thereby forming the "current loop".

[0207] Meanwhile, the main antenna unit 21 also excites the radiation of the parasitic antenna unit 22. Specifically, under the excitation of the current on the first radiation branch 211, the first radiation branch 211 couples energy to the second radiation branch 221 through magnetic field coupling to achieve coupled feeding of the second radiation branch 221, thereby exciting the second radiation branch 221 to perform radiation with the radiation characteristics of a current loop antenna. For example, the second radiation branch 221 is excited to generate a uniform magnetic field for radiation. FIG. 16(b) shows a schematic diagram of the current loop formed on the parasitic antenna unit 22. As shown in FIG. 16(b), the current excited on the second radiation branch 221 of the parasitic antenna unit 22 is opposite in direction to the current excited on the portion of the second reference ground 62 close to the second radiation branch 221. Therefore, the current on the second radiation branch 221 and the current on the portion of the second reference ground 62 close to the second radiation branch 221 form a closed second radiation current loop, thereby also forming a "current loop".

[0208] Next, in combination with Figure 17 the schematic diagram shown, the principle of the electric field and current generated by exciting the eigenmode of the folded floor 60 in the antenna solution provided by the embodiment of the present application will be analyzed. As Figure 17As shown, when the electronic device 100 is in the folded state and the main antenna unit 21 is operating, a longitudinal current is excited on the first radiation branch 211, and the magnetic field induced around the first radiation branch 211 simultaneously surrounds the first radiation branch 211 and the second radiation branch 221. Since the first radiation branch 211 and the second radiation branch 221 share the same magnetic field, according to Lenz's law, a longitudinal current in the same direction can also be induced on the second radiation branch 221. That is to say, the first radiation branch 211 and the second radiation branch 221 are coupled through the magnetic field, and the first radiation branch 211 can couple a current in the same direction on the second radiation branch 221, that is, the current directions on the first radiation branch 211 and the second radiation branch 221 are the same.

[0209] Since both the main antenna unit 21 and the parasitic antenna unit 22 are antenna structures with the radiation characteristics of a current loop antenna, and, as described above, the current induced on the first radiation branch 211 is opposite to the current induced on the part of the first reference ground 61 close to the first radiation branch 211, and the current induced on the second radiation branch 221 of the parasitic antenna unit 22 is opposite to the current induced on the part of the second reference ground 62 close to the second radiation branch 221, therefore, the longitudinal current directions on the first reference ground 61 and the second reference ground 62 are the same, so as to achieve the purpose of enhancing the excitation of the longitudinal mode.

[0210] In addition, since the same-direction currents are generated on the first radiation branch 211 and the second radiation branch 221, the same-direction currents are also induced on the first reference ground 61 near the first radiation branch 211 and the second reference ground 62 near the second radiation branch 221, and the upper and lower ground planes are both positively charged. Thus, in the gap G0, the electric field induced by the first radiation branch 211 and the electric field induced by the second radiation branch 221 will cancel each other out, so that no electric field is generated in the gap G0, or the electric field generated by the main antenna unit 21 in the gap G0 will be weakened.

[0211] It can be understood that when the main antenna unit 21 and the parasitic antenna unit 22 are overlapped and their resonant structures are similar and the resonant points are close, the electric field in the gap G0 can achieve the effect of complete cancellation. When the electric field in the gap G0 is completely cancelled or weakened, no transverse current is generated on the inner surfaces of the upper and lower ground planes, or the transverse current is weakened. Thus, the transverse current distribution of the gap mode is destroyed, so as to achieve the purpose of suppressing the excitation of the gap mode of the folded ground plane 60.

[0212] FIG. 18(a) shows a simulation schematic diagram of the current distribution when the main antenna unit 21 and the parasitic antenna unit 22 are in resonance. As shown in FIG. 18(a), when both the main antenna unit 21 and the parasitic antenna unit 22 adopt an antenna structure capable of current loop radiation, when the electronic device 100 is in a folded state and the main antenna unit 21 is operating, the main antenna unit 21 excites a closed clockwise current loop on the first radiation branch 211 and the first reference ground 61, and also excites a closed clockwise current loop on the second radiation branch 221 and the second reference ground 62. Among them, the current direction on the first radiation branch 211 is the same as the current direction on the second radiation branch 221, the current direction on the first radiation branch 211 is opposite to the current direction on the first reference ground 61, the current direction on the second radiation branch 221 is opposite to the current direction on the second reference ground 62, and the current direction on the first reference ground 61 is the same as the current direction on the second reference ground 62.

[0213] FIG. 18(b) shows a simulation schematic diagram of the magnetic field distribution when the main antenna unit 21 and the parasitic antenna unit 22 are in resonance. As shown in FIG. 18(b), when both the main antenna unit 21 and the parasitic antenna unit 22 adopt an antenna structure capable of current loop radiation, the magnetic field in the gap G0 is basically distributed along the transverse direction of the folded floor 60, indicating that the current in the gap G0 is distributed along the longitudinal direction of the folded floor 60. Thus, the transverse current distribution of the gap mode is basically destroyed. That is to say, the gap mode of the folded floor 60 is suppressed, so it is difficult for the gap mode to be excited.

[0214] Based on the current distribution shown in FIG. 18(a) and the magnetic field distribution shown in FIG. 18(b), FIG. 18(c) shows a simulation schematic diagram of the current distribution corresponding to the eigenmode of the folded floor 60 excited by the main antenna unit 21 and the parasitic antenna unit 22. When both the main antenna unit 21 and the parasitic antenna unit 22 adopt an antenna structure capable of current loop radiation, since longitudinal currents in the same direction are simultaneously excited on the upper and lower reference grounds of the folded floor 60, that is, the first reference ground 61 and the second reference ground 62, a magnetic field perpendicular to the outside will basically not be generated in the gap G0. Therefore, the excitation of the transverse current will be reduced. As shown in FIG. 18(c), the longitudinal mode of the folded floor 60 is enhanced, while the gap mode is significantly weakened. Thus, when the gap mode is weakened and the transverse current is significantly reduced, the energy that can be absorbed or consumed by the high-loss material in the gap G0 is reduced. Therefore, the antenna efficiency of the electronic device 100 in the folded state can be improved, thereby enhancing the radiation ability.

[0215] Comparing FIG. 11(a) and FIG. 18(c), it can be seen that for the antenna structure provided in this embodiment, by adding parasitic antenna units, and both the main antenna unit and the parasitic antenna unit adopt antenna structures capable of current loop radiation, the excitation effect on the longitudinal mode of the folding floor 60 far exceeds that of a common IFA antenna on the longitudinal mode of the folding floor 60.

[0216] In addition, as can be seen from FIG. 18(c), there is still a small amount of transverse current at the corner position of the connecting portion 13. This is because the setting positions of the radiation branches of the main antenna unit 21 and the parasitic antenna unit 22 deviate from the middle of the edge of the corresponding main body. Through simulation results, it is found that when the first radiation branch 211 is provided at the middle of the edge of the first main body 11 opposite to the connecting portion 13, and the second radiation branch 221 is provided at the middle of the edge of the second main body 12 opposite to the connecting portion 13, that is, the first edge region B1 is located at the middle of the edge of the first main body 11 opposite to the connecting portion 13, and the second edge region B2 is located at the middle of the edge of the second main body 12 opposite to the connecting portion 13, the transverse current at the corner position of the connecting portion 13 will basically disappear. In this way, the antenna efficiency in the folded state can be further improved, enabling the electronic device to obtain better antenna performance in the folded state.

[0217] According to Figure 15 Based on the various implementation forms of the main antenna unit 21 and the parasitic antenna unit 22 listed, there are at least twenty-five pairwise combination implementation forms of the main antenna unit 21 and the parasitic antenna unit 22. Thus, in specific applications, according to the actual antenna design requirements in the foldable electronic device, various different antenna combination forms can be flexibly adopted to improve the antenna efficiency of the electronic device in the folded state, enabling the electronic device to obtain good antenna performance in the folded state.

[0218] Next, several combination implementation forms of the antenna structure will be used to give examples of the structures of the main antenna unit 21 and the parasitic antenna unit 22, so as to more clearly illustrate the magnetic field coupling antenna solution provided by the embodiments of the present application.

[0219] In one embodiment, as Figure 19 shown, the main antenna unit 21 is a current loop slot antenna, and the parasitic antenna unit 22 is a current loop left-handed antenna.

[0220] Please also refer to Figure 19As shown in FIGS. 20(a), the radiation branches 211 of the current loop slot antenna 21 include two radiators L11 and L12 with opposite ends, and the two radiators L11 and L12 are separated by a gap, and a gap is formed between the two radiators L11, L12 and the first reference ground 61. The opposite ends of the two radiators L11 and L12 are coupled by a first capacitor C1, and the other ends of the two radiators L11 and L12 are directly coupled to the first reference ground 61 respectively.

[0221] In different implementations, the capacitance value of the first capacitor C1 can be determined according to the operating frequency band of the current loop slot antenna 21. It can be understood that due to the setting of the first capacitor C1, based on the energy storage characteristic of the capacitor for electric energy, the difference in current distribution at different positions on the radiators L11 and L12 at the same moment is not too large, that is, uniform currents are generated on the radiators L11 and L12. Based on the uniform currents on the radiators L11 and L12, uniform currents can also be generated on the first reference ground 61, and the current direction on the first reference ground 61 is opposite to the current direction on the radiators L11 and L12, so as to form a closed uniform current loop between the radiators L11 and L12 and the first reference ground 61 in their vicinity, and thus a uniformly distributed magnetic field can be obtained in the space near the radiators L11 and L12, so that the effect of current loop radiation is achieved.

[0222] In Figure 19 the shown embodiment, the current loop slot antenna 21 is used as the main antenna unit, and the current loop slot antenna 21 further includes a feeding point P0 for feeding the radiation branches of the current loop slot antenna 21.

[0223] In one embodiment, the feeding form of the radiation branches of the current loop slot antenna 21 is a direct feeding form, that is, the radiation branches of the current loop slot antenna 21 are coupled to the feeding point P0 and are used to generate a current under the excitation of the feeding point P0 to perform radiation with the radiation characteristics of a current loop antenna. Specifically, as Figure 19 shown in FIGS. 20(a), the opposite ends of the two radiators L11 and L12 of the radiation branches 211 of the current loop slot antenna 21 are respectively coupled to the feeding point P0.

[0224] In another embodiment, the feeding form of the radiation branches 211 of the current loop slot antenna 21 is a coupled feeding form. Specifically, as shown in FIG. 20(b), the current loop slot antenna 21 further includes a feeding branch 212. The feeding branch 212 is arranged at an interval from the radiation branch 211, and the feeding branch 212 is arranged between the radiation branch 211 and the first reference ground 61. The feeding point P0 is arranged on the feeding branch 212. The feeding branch 212 is used to perform coupled feeding on the radiation branch 211, that is, the feeding branch 212 couples energy to the radiation branch 211 through electric field / magnetic field coupling to excite the radiation branch 211 to perform current loop radiation. More specifically, the feeding branch 212 includes a first feeding part L01 and a second feeding part L02 with opposite ends. One end of the first feeding part L01 is coupled to one end of the feeding point P0, and one end of the second feeding part L02 is coupled to the other end of the feeding point P0. The other ends of the first feeding part L01 and the second feeding part L02 are respectively coupled to the first reference ground 61.

[0225] Please refer to Figure 19 and FIG. 20(c). The radiation branch 221 of the current loop left-handed antenna 22 includes two radiators L21 and L22 with opposite ends. A gap is formed between the two radiators L21 and L22, and a gap is formed between the two radiators L21, L22 and the second reference ground 62. The opposite ends of the two radiators L21 and L22 are coupled through a first capacitor C1. One end of the radiator L21 far from the radiator L22 is coupled to the second reference ground 62 through a fourth capacitor C0 (such as a left-handed capacitor), and one end of the radiator L22 far from the radiator L21 is directly coupled to the second reference ground 62.

[0226] In different implementations, the capacitance values of the fourth capacitor C0 and the first capacitor C1 can be determined according to the operating frequency band of the current loop left-handed antenna 22. Among them, the setting of the fourth capacitor C0 can be used to excite the two radiators L21 and L22 to generate corresponding left-handed mode resonances for radiation.

[0227] For the principle of magnetic field coupling and radiation with the radiation characteristics of a current loop antenna between the current loop slot antenna 21 and the current loop left-handed antenna 22, please refer to the detailed introduction of the main antenna unit 21 and the parasitic antenna unit 22 shown above Figure 14 and no repeated description will be given here.

[0228] In another embodiment, as Figure 21 shown, the main antenna unit 21 is a current loop left-handed antenna, and the parasitic antenna unit 22 is a current loop monopole antenna.

[0229] Figure 21 The structure of the current-loop left-handed antenna 21 shown is the same as that of Figure 19 the current-loop left-handed antenna 22 shown, except that: Figure 21 The current-loop left-handed antenna 21 shown is used as the main antenna unit. The current-loop left-handed antenna 21 further includes a feeding point P0, and the feeding point P0 is used to feed the radiation branches of the current-loop left-handed antenna 21.

[0230] In one embodiment, the feeding form of the radiation branches of the current-loop left-handed antenna 21 is a direct feeding form, that is, the radiation branches of the current-loop left-handed antenna 21 are coupled to the feeding point P0 and are used to generate a current under the excitation of the feeding point P0 to perform radiation with the radiation characteristics of a current-loop antenna. Specifically, as Figure 21 shown in and Figure 22(a), one end of the radiator L21 of the radiation branch 211 of the current-loop left-handed antenna 21, which is far from the radiator L22, is coupled to the feeding point P0 through the fourth capacitor C0.

[0231] In another embodiment, the feeding form of the radiation branches of the current-loop left-handed antenna 21 is a coupled feeding form. Specifically, as shown in Figure 22(b), the current-loop left-handed antenna 21 further includes a feeding branch 212. The feeding branch 212 is arranged at an interval from the radiation branch 211, and the feeding branch 212 is arranged between the radiation branch 211 and the first reference ground 61. The feeding point P0 is arranged on the feeding branch 212. Among them, the structure and the coupled feeding principle of the feeding branch 212 shown in Figure 22(b) are the same as those of the feeding branch 212 shown in Figure 20(b). For specific technical details, please refer to the above specific introduction of the feeding branch 212 shown in Figure 20(b), and will not be repeated here.

[0232] Please refer to together Figure 21As shown in FIGS. 22(c), the radiation branch 221 of the current loop monopole antenna 22 includes at least one radiator L31, and the radiator L31 is spaced apart from the second reference ground 62 by a slit. In this embodiment, in order to be able to excite and obtain a uniform magnetic field, one end of the radiator L31 is coupled to the second reference ground 62 through a second capacitor C2, and the other end is coupled to the second reference ground 62 through a third capacitor C3. Wherein, the capacitance values of the second capacitor C2 and the third capacitor C3 may be the same or different. The length of the radiation branch 221 of the current loop monopole antenna 22, that is, the length of the radiator L31, may be related to the operating frequency band of the current loop monopole antenna 22. For example, the length of the radiator L31 may be less than or equal to 1 / 4 of the operating wavelength corresponding to the operating frequency band of the current loop monopole antenna 22. Wherein, the operating wavelength corresponding to the operating frequency band may be the wavelength corresponding to the center frequency point of the operating frequency band.

[0233] For the principle of magnetic field coupling between the current loop left-handed antenna 21 and the current loop monopole antenna 22 and the radiation having the radiation characteristics of the current loop antenna, please refer to the above description of Figure 14 the detailed introduction of the main antenna unit 21 and the parasitic antenna unit 22 shown, and will not be repeated here.

[0234] In another embodiment, as shown in Figure 23 the main antenna unit 21 is a current loop monopole antenna, and the parasitic antenna unit 22 is a left-handed antenna.

[0235] Figure 23 The structure of the current loop monopole antenna 21 shown in is similar to the structure of the current loop monopole antenna 22 shown in, except that: Figure 21 The current loop monopole antenna 21 shown in is used as the main antenna unit, and the current loop monopole antenna 21 further includes a feeding point P0, and the feeding point P0 is used to feed the radiation branch of the current loop monopole antenna 21. Figure 23 In one embodiment, the feeding form of the radiation branch of the current loop monopole antenna 21 is a direct feeding form, that is, the radiation branch of the current loop monopole antenna 21 is coupled to the feeding point P0 and is used to generate a current under the excitation of the feeding point P0 to perform radiation having the radiation characteristics of the current loop antenna. Specifically, as shown in FIGS. 24(a), one end of the radiator L31 of the radiation branch 211 of the current loop monopole antenna 21 is coupled to the feeding point P0 through the second capacitor C2.

[0236] Figure 23

[0237] ​​In another embodiment, the feeding form of the radiation branches of the current loop monopole antenna 21 is a coupled feeding form. Specifically, as shown in FIG. 24(b), the current loop monopole antenna 21 further includes a feeding branch 212. The feeding branch 212 is arranged at an interval from the radiation branch 211, and the feeding branch 212 is arranged between the radiation branch 211 and the first reference ground 61. The feeding point P0 is arranged on the feeding branch 212. Among them, the structure and the coupled feeding principle of the feeding branch 212 shown in FIG. 24(b) are the same as those of the feeding branch 212 shown in FIG. 20(b). For specific technical details, please refer to the above specific introduction of the feeding branch 212 shown in FIG. 20(b), and will not be repeated here.

[0238] Please refer to Figure 23 and FIG. 24(c). The radiation branch 221 of the left-handed antenna 22 includes a radiator L41. The radiator L41 is spaced apart from the second reference ground 62 by a gap. One end of the radiator L41 is coupled to the second reference ground 62 through a fourth capacitor C0 (such as a left-handed capacitor), and the other end is directly coupled to the second reference ground 62.

[0239] In different implementations, the capacitance value of the fourth capacitor C0 can be determined according to the operating frequency band of the left-handed antenna 22. Among them, the setting of the fourth capacitor C0 can be used to excite the radiator L41 to generate resonance in the corresponding left-handed mode for radiation.

[0240] For the principle of magnetic field coupling and the radiation with the radiation characteristics of the current loop antenna between the current loop monopole antenna 21 and the left-handed antenna 22, please refer to the above Figure 14 detailed introduction of the main antenna unit 21 and the parasitic antenna unit 22 shown, and will not be repeated here.

[0241] In another embodiment, as Figure 25 shown, the main antenna unit 21 is a current loop dipole antenna, and the parasitic antenna unit 22 is a current loop slot antenna.

[0242] Please refer to Figure 25As shown in FIGS. 26(a), the radiation branches 211 of the current loop dipole antenna 21 include two radiators L51 and L52 with opposite ends, and the two radiators L51 and L52 are spaced apart by a gap, and a gap is formed between the two radiators L51, L52 and the first reference ground 61. The opposite ends of the two radiators L51 and L52 are coupled by a first capacitor C1. One end of the radiator L51 far from the radiator L52 is coupled to the first reference ground 61 by a second capacitor C2, and one end of the radiator L52 far from the radiator L51 is coupled to the first reference ground 61 by a third capacitor C3.

[0243] In different implementations, the capacitance values of the first capacitor C1, the second capacitor C2, and the third capacitor C3 can be determined according to the operating frequency band of the current loop dipole antenna 21. It can be understood that due to the setting of the first capacitor C1, based on the energy storage characteristic of the capacitor for electric energy, the difference in the current distribution at different positions on the radiators L51 and L52 at the same moment is not too large, that is, uniform currents are generated on the radiators L51 and L52. Based on the uniform currents on the radiators L51 and L52, uniform currents can also be generated on the first reference ground 61, and the current direction on the first reference ground 61 is opposite to the current directions on the radiators L51 and L52, so as to form a closed uniform current loop between the radiators L51 and L52 and the first reference ground 61 in the vicinity thereof, and thus a uniformly distributed magnetic field can be obtained in the space near the radiators L51 and L52, and in this way, the effect of current loop radiation is achieved.

[0244] In some embodiments, the length of the radiation branches of the current loop dipole antenna 21, that is, the total length of the radiators L51 and L52, can be related to the operating frequency band of the current loop dipole antenna. For example, the total length can be less than 1 / 2 of the operating wavelength corresponding to the operating frequency band of the current loop dipole antenna 21 and greater than 1 / 4 of the operating wavelength.

[0245] It should be noted that in different embodiments, the length relationship between the radiators L51 and L52 can be flexible. For example, the radiators L51 and L52 can have the same size, or the length of the radiator L51 can be less than or greater than the length of the radiator L52. Thus, the position of the capacitor C1 provided between the radiators L51 and L52 can also be flexible.

[0246] In Figure 25In the embodiment shown, the current loop dipole antenna 21 is used as the main antenna unit. The current loop dipole antenna 21 further includes a feeding point P0, and the feeding point P0 is used to feed the radiation branches of the current loop dipole antenna 21.

[0247] In one embodiment, the feeding form of the radiation branches of the current loop dipole antenna 21 is a direct feeding form, that is, the radiation branches of the current loop dipole antenna 21 are coupled to the feeding point P0 and are used to generate a current under the excitation of the feeding point P0 to perform radiation with the radiation characteristics of a current loop antenna. Specifically, as Figure 25 shown in and Figure 26(a), the opposite ends of the two radiators L51 and L52 of the radiation branch 211 of the current loop dipole antenna 21 are also respectively coupled to the feeding point P0.

[0248] In another embodiment, the feeding form of the radiation branch 211 of the current loop dipole antenna 21 is a coupled feeding form. Specifically, as shown in Figure 26(b), the current loop dipole antenna 21 further includes a feeding branch 212. The feeding branch 212 is arranged at an interval from the radiation branch 211, and the feeding branch 212 is arranged between the radiation branch 211 and the first reference ground 61, and the feeding point P0 is arranged on the feeding branch 212. Among them, the structure of the feeding branch 212 shown in Figure 26(b) and the coupled feeding principle are the same as those of the feeding branch 212 shown in Figure 20(b). For specific technical details, please refer to the specific introduction of the feeding branch 212 shown in Figure 20(b) above, and will not be repeated here.

[0249] Figure 25 The structure of the current loop slot antenna 22 shown is the same as Figure 19 that of the current loop slot antenna 21 shown, the difference is that: Figure 25 The current loop slot antenna 22 shown is used as a parasitic antenna unit. As shown in Figure 26(c), only a first capacitor C1 is provided between the opposite ends of the two radiators L11 and L12 of the current loop slot antenna 22, and no feeding point P0 is provided.

[0250] For the principle of magnetic field coupling between the current loop dipole antenna 21 and the current loop slot antenna 22 and the radiation with the radiation characteristics of a current loop antenna, please refer to the detailed introduction of the main antenna unit 21 and the parasitic antenna unit 22 shown above, and will not be repeated here. Figure 14 shown, and will not be repeated here.

[0251] In another embodiment, as Figure 27 shown, the main antenna unit 21 is a left-handed antenna, and the parasitic antenna unit 22 is a current loop dipole antenna.

[0252] Figure 27 The structure of the left - hand antenna 21 shown is the same as that of Figure 23 the left - hand antenna 22 shown, except that: Figure 27 The current - loop left - hand antenna 21 shown is used as the main antenna unit. The current - loop left - hand antenna 21 further includes a feeding point P0, and the feeding point P0 is used to feed the radiation branches of the left - hand antenna 21.

[0253] In one embodiment, the radiation branches of the left - hand antenna 21 are coupled to the feeding point P0 and are used to generate a current under the excitation of the feeding point P0 to perform radiation with the radiation characteristics of a current - loop antenna. Specifically, as Figure 27 shown in and Figure 28(a), one end of the radiator L41 of the radiation branch 211 of the left - hand antenna 21 is coupled to the feeding point P0 through the fourth capacitor C0, and the other end is directly coupled to the first reference ground 61.

[0254] Figure 27 The structure of the current - loop dipole antenna 22 shown is the same as that of Figure 25 the current - loop dipole antenna 21 shown, except that: Figure 27 The current - loop dipole antenna 22 shown is used as a parasitic antenna unit. As shown in Figure 28(b), only the first capacitor C1 is provided between the opposite ends of the two radiators L51 and L52 of the current - loop dipole antenna 22, and the feeding point P0 is not provided.

[0255] For the principle of magnetic field coupling and the radiation with the radiation characteristics of a current - loop antenna between the left - hand antenna 21 and the current - loop dipole antenna 22, please refer to the above - mentioned detailed introduction to Figure 14 the main antenna unit 21 and the parasitic antenna unit 22 shown, and no repeated description will be given here.

[0256] In another embodiment, as Figure 29 shown, both the main antenna unit 21 and the parasitic antenna unit 22 are left - hand antennas. Among them, Figure 29 the structure of the left - hand antenna 21 shown is the same as that of Figure 27 the left - hand antenna 22 shown, Figure 29 the structure of the left - hand antenna 22 shown is the same as that of Figure 23 the left - hand antenna 22 shown. For the specific technical details, please refer to the above - mentioned detailed introduction to Figure 14 the main antenna unit 21 and the parasitic antenna unit 22 shown, and no repeated description will be given here.

[0257] As described above, according to Figure 15For the various implementation forms of the main antenna unit 21 and the parasitic antenna unit 22 listed, there are at least twenty-five implementation forms of pairwise combinations of the main antenna unit 21 and the parasitic antenna unit 22. Figure 14 and Figures 19 - 29 Only the structural diagrams of 7 combinations are given. Among them, the structural diagrams of various current loop antennas and left-handed antennas used as the main antenna unit and the parasitic antenna unit are respectively exemplified. On this basis, those skilled in the art can easily understand and obtain the structural diagrams of other combination implementation forms not shown in the drawings in this application. Therefore, the structural diagrams of other combinations will not be listed and introduced one by one herein.

[0258] In the above current loop antenna provided by the embodiment of the present application, for example Figure 19 as shown, one or more of the first capacitors C1 can be connected in series on the radiator, so that the magnetic field distribution obtained by exciting the current loop antenna is more uniform, so as to achieve the effect of improving the radiation efficiency of the antenna. Among them, the capacitance value of the first capacitor C1 connected in series on the radiator can be determined according to the operating frequency band of the corresponding current loop antenna. For example, when the operating frequency band of the current loop antenna is low frequency (Low Band, LB), the value range of the capacitance value of the series-connected first capacitor C1 provided on the radiator is [2 pF, 25 pF]. When the operating frequency band of the current loop antenna is medium frequency (Mid Band, MB), the value range of the capacitance value of the series-connected first capacitor C1 provided on the radiator is within [0.8 pF, 12 pF]. When the operating frequency band of the current loop antenna is high frequency (High Band, HB), the value range of the capacitance value of the series-connected first capacitor C1 provided on the radiator is [0.2 pF, 8 pF].

[0259] Among them, the low, medium, and high frequency bands include, but are not limited to, Bluetooth (BT) communication technology, global positioning system (GPS) communication technology, wireless fidelity (Wi-Fi) communication technology, global system for mobile communications (GSM) communication technology, wideband code division multiple access (WCDMA) communication technology, long term evolution (LTE) communication technology, 5G communication technology, SUB-6G communication technology, and other future communication technologies. The LB band can be a band covering 450 MHz - 1 GHz, the MB band can be a band covering 1 GHz - 3 GHz, and the HB band can be a band covering 3 GHz - 10 GHz, including common bands such as 5G NR, WiFi 6E, and UWB.

[0260] In the current loop antenna provided by the embodiment of the present application, in a specific design, for example Figure 21 As shown, at least one second capacitor C2 and / or third capacitor C3 can be provided at the end of the radiator. Among them, the capacitance values of the second capacitor C2 and the third capacitor C3 provided at the end can be determined according to the operating frequency band of the corresponding current loop antenna. For example, when the operating frequency band of the current loop antenna is the low frequency (Low Band, LB), the value range of the capacitance of the second capacitor C2 and the third capacitor C3 provided at the end of the radiator is [1.5 pF, 15 pF]. When the operating frequency band of the current loop antenna is the medium frequency (Mid Band, MB), the value range of the capacitance of the second capacitor C2 and the third capacitor C3 provided at the end of the radiator is within [0.5 pF, 15 pF]. When the operating frequency band of the current loop antenna is the high frequency (High Band, HB), the value range of the capacitance of the second capacitor C2 and the third capacitor C3 provided at the end of the radiator is [1.2 pF, 12 pF].

[0261] It should be noted that the above example of the value range of the capacitance is only an example, and in different environments, the capacitance value of the capacitor can also be set flexibly.

[0262] Figure 30 Shows a schematic diagram of the simulation efficiency curve of a conventional antenna scheme and a schematic diagram of the simulation efficiency curve of an antenna scheme provided by the embodiment of the present application. Among them, Figure 30 The curve S1 shown in represents Figures 7 - 10The radiation efficiency corresponding to the conventional antenna solution of the ordinary left - hand antenna shown without a parasitic structure. Curve S2 represents Figures 7 - 10 The system efficiency corresponding to the conventional antenna solution of the ordinary left - hand antenna shown without a parasitic structure. Curve S3 represents Figure 14 The radiation efficiency corresponding to the solution where both the main antenna unit and the parasitic antenna unit adopt current - loop slot antennas. Curve S4 represents Figure 14 The system efficiency corresponding to the solution where both the main antenna unit and the parasitic antenna unit adopt current - loop slot antennas.

[0263] Comparing the curves S1 and S3, it can be seen that for the antenna solution where both the main antenna unit and the parasitic antenna unit adopt current - loop slot antennas capable of current - loop radiation, compared with the conventional antenna solution of the ordinary left - hand antenna without a parasitic structure, the antenna radiation efficiency of the folded - state electronic device is improved in the low - frequency band. For example, the average value of the antenna radiation efficiency in the LTE B5 (0.824 GHz - 0.894 GHz) band is increased by about 4 dB.

[0264] Comparing the curves S2 and S4, it can be seen that for the antenna solution where both the main antenna unit and the parasitic antenna unit adopt current - loop slot antennas capable of current - loop radiation, compared with the conventional antenna solution of the ordinary left - hand antenna without a parasitic structure, the system efficiency of the folded - state electronic device is improved in the low - frequency band. For example, the average value of the system efficiency in the LTE B5 (0.824 GHz - 0.894 GHz) band is increased by about 4 - 5 dB.

[0265] Figure 31 Shows a schematic diagram of the simulation efficiency curve of a conventional antenna solution and a schematic diagram of the simulation efficiency curve of another antenna solution provided by the embodiment of the present application. Among them, Figure 31 The curve S1 shown in represents Figures 7 - 10 The radiation efficiency corresponding to the conventional antenna solution of the ordinary left - hand antenna shown without a parasitic structure. Curve S2 represents Figures 7 - 10 The system efficiency corresponding to the conventional antenna solution of the ordinary left - hand antenna shown without a parasitic structure. Curve S3 represents Figure 29 The radiation efficiency corresponding to the solution where both the main antenna unit and the parasitic antenna unit adopt left - hand antennas. Curve S4 represents Figure 29 The system efficiency corresponding to the solution where both the main antenna unit and the parasitic antenna unit adopt left - hand antennas.

[0266] Comparing the curves S1 and S3, it can be seen that both the main antenna unit and the parasitic antenna unit adopt the antenna scheme of a left-handed antenna capable of current loop radiation. Compared with the conventional antenna scheme of a common left-handed antenna without a parasitic structure, the antenna radiation efficiency of the foldable electronic device is improved in the low-frequency band. For example, the average value of the antenna radiation efficiency in the LTE B20 (0.791 GHz - 0.862 GHz) band is increased by about 2.5 dB.

[0267] Comparing the curves S2 and S4, it can be seen that both the main antenna unit and the parasitic antenna unit adopt the antenna scheme of a left-handed antenna capable of current loop radiation. Compared with the conventional antenna scheme of a common left-handed antenna without a parasitic structure, the system efficiency of the foldable electronic device is improved in the low-frequency band. For example, the average value of the system efficiency in the LTE B20 (0.791 GHz - 0.862 GHz) band is increased by about 1 - 2 dB.

[0268] Based on Figure 30 and Figure 31 it can be known that when both the main antenna unit and the parasitic antenna unit adopt an antenna structure with the characteristics of current loop antenna radiation, such as a current loop antenna or a left-handed antenna, the antenna efficiency of the electronic device 100 in the folded state can be significantly improved.

[0269] In summary, in the foldable electronic device provided in this application, by respectively arranging opposite main antenna units and parasitic antenna units in the edge regions of its two foldable bodies, and both the main antenna unit and the parasitic antenna unit adopt an antenna structure with the characteristics of current loop antenna radiation, magnetic field coupling between the main antenna unit and the parasitic antenna unit is utilized in the folded state to form current loop radiation on both the first radiation branch and the second radiation branch, and co-directional currents are excited on the radiation branches of the two antenna units. According to the characteristics of current loop radiation, co-directional longitudinal currents can be simultaneously excited on the two overlapping floors of the folded floor of the electronic device. In this way, on the one hand, the reverse transverse current generated by the gap mode in the folded state on the folded floor can be suppressed by the co-directional longitudinal currents on the two overlapping floors, so as to achieve the purpose of suppressing the excitation of the gap mode, reducing or eliminating the energy consumed in the folded state, and further improving the antenna efficiency in the folded state; on the other hand, the excitation effect of the longitudinal mode of the folded floor can be enhanced by the superposition effect of the co-directional longitudinal currents on the two overlapping floors, so as to achieve the purpose of further improving the antenna efficiency in the folded state, enabling the electronic device 100 to obtain better folded-state antenna performance and effectively solving the problem of poor low-frequency antenna efficiency of the foldable electronic device 100 in the folded state.

[0270] The above is only a partial implementation manner of the present application. The protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, and all should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An antenna system, applied to a foldable electronic device, the foldable electronic device comprising: A first body and a second body connected to each other and capable of being folded or unfolded relative to each other, and a first reference ground corresponding to the first body and a second reference ground corresponding to the second body; characterized in that the antenna system comprises: a main antenna unit, which is a current loop antenna, comprising a feeding point and a first radiation branch disposed on the first body, wherein the feeding point is used to feed the first radiation branch; and The parasitic antenna unit is a current loop antenna, and the parasitic antenna unit includes a second radiation branch disposed on the second body; When the electronic device is in a folded state, the main antenna unit is used to excite a closed current loop on the first radiation branch and the first reference ground, the current direction on the first radiation branch is opposite to the current direction on the first reference ground, the first radiation branch and the second radiation branch are at least partially overlapped, the first radiation branch is used to perform magnetic field coupling with the second radiation branch to form current loop radiation on both the first radiation branch and the second radiation branch, and to excite a closed current loop on the second radiation branch and the second reference ground, the current direction on the second radiation branch is opposite to the current direction on the second reference ground, the current direction on the first radiation branch is the same as the current direction on the second radiation branch, and the current directions on the first reference ground and the second reference ground are the same.

2. The antenna system according to claim 1, characterized in that The main antenna unit and the parasitic antenna unit are respectively any one of a current loop slot antenna, a current loop monopole antenna, a current loop dipole antenna, a current loop left-hand antenna, and a left-hand antenna.

3. The antenna system according to claim 2, characterized in that: The electronic device further comprises a connecting portion provided between the first body and the second body, and the first body and the second body are connected via the connecting portion; The first radiating branch is arranged at an edge of the first body opposite to the connecting portion, and the second radiating branch is arranged at an edge of the second body opposite to the connecting portion.

4. The antenna system according to claim 3, characterized in that: The first radiating branch is arranged at the middle of the edge where the first body and the connecting portion are arranged oppositely, and the second radiating branch is arranged at the middle of the edge where the second body and the connecting portion are arranged oppositely.

5. The antenna system according to any one of claims 1 to 4, characterized in that: The first radiation branch is coupled to the feeding point, and the first radiation branch is used to generate current under the excitation of the feeding point and perform radiation with the radiation characteristics of the current loop antenna; or, The main antenna unit also includes a feeding branch, the feeding point is arranged on the feeding branch, the feeding branch is spaced apart from the first radiating branch, and the feeding branch couples energy to the first radiating branch through electric field / magnetic field coupling to stimulate the first radiating branch to perform current loop radiation.

6. The antenna system according to any one of claims 1 to 4, characterized in that: The main antenna unit and / or the parasitic antenna unit is a current loop slot antenna, the radiation branch of the current loop slot antenna includes two radiators with opposite ends, the opposite ends of the two radiators are coupled through a first capacitor, the other ends of the two radiators are respectively coupled to corresponding reference grounds, and a gap is formed between the two radiators and the reference ground; or, The main antenna unit and / or the parasitic antenna unit is a current loop monopole antenna, the radiation branch of the current loop monopole antenna includes a radiator, one end of the radiator is coupled to the corresponding reference ground or the feeding point through a second capacitor, and the other end is coupled to the corresponding reference ground through a third capacitor; the length of the radiation branch of the current loop monopole antenna is less than one quarter of the working wavelength of the current loop monopole antenna; or, The main antenna unit and / or the parasitic antenna unit is a current loop dipole antenna, the radiation branch of the current loop dipole antenna includes two radiators with opposite ends, the opposite ends of the two radiators are coupled through a first capacitor, the other end of one of the two radiators is coupled to a corresponding reference ground through a second capacitor, and the other end of the other radiator is coupled to the corresponding reference ground through a third capacitor; the length of the radiation branch of the current loop dipole antenna is less than half of the working wavelength of the current loop dipole antenna; or, The main antenna unit and / or the parasitic antenna unit is a current loop left-hand antenna, the radiation branch of the current loop left-hand antenna includes two radiators with opposite ends, the opposite ends of the two radiators are coupled through a first capacitor, the other end of one of the two radiators is coupled to the corresponding reference ground or the feeding point through a fourth capacitor, and the other end of the other radiator is coupled to the corresponding reference ground; or, The main antenna unit and / or the parasitic antenna unit is a left-hand antenna, and the radiation branch of the left-hand antenna includes a radiator, one end of the radiator is coupled to the corresponding reference ground or the feeding point through a fourth capacitor, and the other end is coupled to the corresponding reference ground.

7. The antenna system according to claim 6, characterized in that: When the operating frequency band of the main antenna unit or the parasitic antenna unit is 450 MHz-1 GHz, the capacitance value of the first capacitor is in the range of [2 pF, 25 pF]; When the operating frequency band of the main antenna unit or the parasitic antenna unit is 1 GHz-3 GHz, the capacitance value of the first capacitor is in the range of [0.8 pF, 12 pF]; When the operating frequency band of the main antenna unit or the parasitic antenna unit is 3 GHz-10 GHz, the capacitance value of the first capacitor is in the range of [0.2 pF, 8 pF].

8. The antenna system according to claim 6, characterized in that When the operating frequency band of the main antenna unit or the parasitic antenna unit is 450 MHz-1 GHz, the capacitance values ​​of the second capacitor and the third capacitor are in the range of [1.5 pF, 15 pF]; When the operating frequency band of the main antenna unit or the parasitic antenna unit is 1 GHz-3 GHz, the capacitance values ​​of the second capacitor and the third capacitor are in the range of [0.5 pF, 15 pF]; When the operating frequency band of the main antenna unit or the parasitic antenna unit is 3 GHz-10 GHz, the capacitance values ​​of the second capacitor and the third capacitor are in the range of [1.2 pF, 12 pF].

9. An antenna system, applied to a foldable electronic device, wherein the foldable electronic device comprises a first body and a second body connected to each other and capable of being folded or unfolded relative to each other; characterized in that: The antenna system comprises: a main antenna unit, comprising a feeding point and a first radiating branch disposed on the first main body, wherein the feeding point is used to feed the first radiating branch; and A parasitic antenna unit, comprising a second radiation branch disposed on the second body; Wherein, when the electronic device is in a folded state, the first radiation branch and the second radiation branch are at least partially overlapped, and the first radiation branch is used to perform magnetic field coupling with the second radiation branch; The main antenna unit is any one of a current loop slot antenna, a current loop monopole antenna, a current loop dipole antenna, a current loop left-hand antenna, and a left-hand antenna; The parasitic antenna unit is any one of a current loop slot antenna, a current loop monopole antenna, a current loop dipole antenna, a current loop left-hand antenna, and a left-hand antenna; For the current loop slot antenna, the radiation branch of the current loop slot antenna includes two radiators with opposite ends, the opposite ends of the two radiators are coupled through a first capacitor, the other ends of the two radiators are respectively coupled to a reference ground, and a gap is formed between the two radiators and the reference ground; For the current loop monopole antenna, the radiation branch of the current loop monopole antenna includes a radiator, one end of the radiator is coupled to the reference ground or the feeding point through a second capacitor, and the other end is coupled to the reference ground through a third capacitor; the length of the radiation branch of the current loop monopole antenna is less than one quarter of the working wavelength of the current loop monopole antenna; For the current loop dipole antenna, the radiation branch of the current loop dipole antenna includes two radiators whose ends are arranged opposite to each other, the opposite ends of the two radiators are coupled through a first capacitor, the other end of one of the two radiators is coupled to a reference ground through a second capacitor, and the other end of the other radiator is coupled to the reference ground through a third capacitor; the length of the radiation branch of the current loop dipole antenna is less than half of the working wavelength of the current loop dipole antenna; For the current loop left-hand antenna, the radiation branch of the current loop left-hand antenna includes two radiators whose ends are arranged opposite to each other, the opposite ends of the two radiators are coupled through a first capacitor, the other end of one of the two radiators is coupled to a reference ground or the feeding point through a fourth capacitor, and the other end of the other radiator is coupled to the reference ground; For the left-hand antenna, the radiation branch of the left-hand antenna includes a radiator, one end of the radiator is coupled to the reference ground or the feeding point through a fourth capacitor, and the other end is coupled to the reference ground; When the electronic device is in a folded state, the main antenna unit and the parasitic antenna unit excite currents in the same direction on the two overlapping reference grounds.

10. The antenna system according to claim 9, characterized in that When the current loop slot antenna is used as the main antenna unit, The opposite ends of the two radiators are also coupled to the feeding point respectively; or The current loop slot antenna also includes a feeding branch, which is spaced apart from a radiating branch of the current loop slot antenna and is arranged between the radiating branch of the current loop slot antenna and the reference ground. The feeding point is arranged on the feeding branch, and the feeding branch is used to couple and feed the radiating branch of the current loop slot antenna.

11. The antenna system according to claim 9, characterized in that When the current loop left-hand antenna is used as the main antenna unit, The other end of one of the radiators is coupled to the feeding point via a fourth capacitor; or The current loop left-hand antenna also includes a feeding branch, which is spaced apart from a radiating branch of the current loop left-hand antenna and is arranged between the radiating branch of the current loop left-hand antenna and the reference ground. The feeding point is arranged on the feeding branch, and the feeding branch is used to couple and feed the radiating branch of the current loop left-hand antenna.

12. The antenna system according to claim 9, characterized in that When the current loop monopole antenna is used as the main antenna unit, One end of the radiator is coupled to the feeding point via the second capacitor; or The current loop monopole antenna also includes a feeding branch, which is spaced apart from a radiating branch of the current loop monopole antenna and is arranged between the radiating branch of the current loop monopole antenna and the reference ground. The feeding point is arranged on the feeding branch, and the feeding branch is used to couple and feed the radiating branch of the current loop monopole antenna.

13. The antenna system according to claim 9, characterized in that When the current loop dipole antenna is used as the main antenna unit, The opposite ends of the two radiators are also coupled to the feeding point respectively; or The current loop dipole antenna also includes a feeding branch, which is spaced apart from a radiating branch of the current loop dipole antenna and is arranged between the radiating branch of the current loop dipole antenna and the reference ground. The feeding point is arranged on the feeding branch, and the feeding branch is used to couple and feed the radiating branch of the current loop dipole antenna.

14. The antenna system according to claim 9, characterized in that When the left-hand antenna is used as a main antenna unit, one end of the radiator is coupled to the feeding point through the fourth capacitor.

15. The antenna system according to claim 9, characterized in that When the operating frequency band of the main antenna unit or the parasitic antenna unit is 450 MHz-1 GHz, the capacitance value of the first capacitor is in the range of [2 pF, 25 pF]; When the operating frequency band of the main antenna unit or the parasitic antenna unit is 1 GHz-3 GHz, the capacitance value of the first capacitor is in the range of [0.8 pF, 12 pF]; When the operating frequency band of the main antenna unit or the parasitic antenna unit is 3 GHz-10 GHz, the capacitance value of the first capacitor is in the range of [0.2 pF, 8 pF].

16. The antenna system according to claim 9, characterized in that When the operating frequency band of the main antenna unit or the parasitic antenna unit is 450 MHz-1 GHz, the capacitance values ​​of the second capacitor and the third capacitor are in the range of [1.5 pF, 15 pF]; When the operating frequency band of the main antenna unit or the parasitic antenna unit is 1 GHz-3 GHz, the capacitance values ​​of the second capacitor and the third capacitor are in the range of [0.5 pF, 15 pF]; When the operating frequency band of the main antenna unit or the parasitic antenna unit is 3 GHz-10 GHz, the capacitance values ​​of the second capacitor and the third capacitor are in the range of [1.2 pF, 12 pF].

17. The antenna system according to claim 9, characterized in that The electronic device further comprises a connecting portion provided between the first body and the second body, and the first body and the second body are connected via the connecting portion; The first radiating branch is arranged at an edge of the first body opposite to the connecting portion, and the second radiating branch is arranged at an edge of the second body opposite to the connecting portion.

18. The antenna system according to claim 17, characterized in that The first radiating branch is arranged at the middle of the edge where the first body and the connecting portion are arranged oppositely, and the second radiating branch is arranged at the middle of the edge where the second body and the connecting portion are arranged oppositely.

19. A foldable electronic device, comprising: The first body and the second body are connected to each other and can be folded or unfolded relative to each other; a first reference ground corresponding to the first body and a second reference ground corresponding to the second body; as well as The antenna system as described in any one of claims 1 to 18, wherein the main antenna unit included in the antenna system is arranged on the first body, and the parasitic antenna unit included in the antenna system is arranged on the second body.

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