Antenna system and folding terminal

Abstract

The present application belongs to the technical field of antennas. Disclosed are an antenna system and a folding terminal. The antenna system comprises a first antenna and a first antenna tuning unit, the first antenna being arranged on a first frame branch of a first device body, one end of the first antenna tuning unit being connected to a first position on a second frame branch of a second device body, and the other end of the first antenna tuning unit being grounded. The first device body is connected to the second device body by means of a shaft, the first frame branch being symmetrical or approximately symmetrical to the second frame branch about the shaft. The first position is the position on the second frame branch where the distance to a current grounding position of the first antenna is smaller than a preset distance when the first device body and the second device body are folded. The first antenna tuning unit is used for triggering a grounding plate to generate a current in a specified direction, so as to induce a current in the second frame branch that has the same current direction as the current the first frame branch.

Description

Antenna system and foldable terminal

[0001] Cross-references

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on September 18, 2023, with application number 202311203782.4 and invention name “Antenna System and Folding Terminal”. The entire contents of the application are incorporated by reference into this application. Technical Field

[0003] The present application belongs to the field of antenna technology, and in particular relates to an antenna system and a foldable terminal. Background Art

[0004] With the development of foldable screen technology, foldable devices (such as foldable phones) are attracting increasing attention as a new product form factor. Foldable devices consist of two parts (usually a main screen and a secondary screen) connected by a hinge. The foldable screen is opened and closed by rotating these two parts.

[0005] The antennas of foldable devices are typically located on the sides of the hinge. When the device is closed, the antenna on one side is affected by the other side and the screen, significantly absorbing the antenna's energy. This degrades antenna performance (such as radiation efficiency) and affects the user's communication experience.

[0006] How to improve the antenna performance of foldable terminals when they are in the folded state is a technical problem that needs to be solved urgently.

[0007] Summary of the Invention

[0008] The purpose of the embodiments of the present application is to provide an antenna system and a foldable terminal to improve the antenna performance of the foldable terminal when it is in a folded state.

[0009] In a first aspect, an embodiment of the present application provides an antenna system, comprising: a first antenna and a first antenna tuning unit;

[0010] The first antenna is arranged on the first frame branch of the first fuselage;

[0011] One end of the first antenna tuning unit is connected to the first position of the second frame branch in the second fuselage, and the other end of the first antenna tuning unit is grounded;

[0012] In which, the first body and the second body are connected by a rotating shaft; the first frame branch and the second frame branch are symmetrical or approximately symmetrical about the rotating shaft; the first position is the position on the second frame branch where the distance from the current return position of the first antenna to the ground is less than a preset distance when the first body and the second body are in a folded state; the first antenna tuning unit is used to trigger the floor to generate a current in a specified direction, so as to induce a current in the second frame branch with the same direction as the current in the first frame branch.

[0013] In a second aspect, a foldable terminal is provided, comprising: the antenna system as described in the first aspect.

[0014] In an embodiment of the present application, when the first antenna is arranged on the first frame branch of the first body, a first antenna tuning unit is introduced at a first position on the second frame branch symmetrical to the first frame branch about the rotation axis. The first antenna tuning unit can trigger the floor to generate a current in a specified direction, so as to induce a current in the second frame branch with the same direction as the current in the first antenna, so that the proportion or intensity of the current in the same direction as the first frame branch on the two frame branches is increased (there is also a current on the second frame branch that is opposite to the current in the first frame branch), thereby reducing the electric field energy coupling loss of the first antenna in the folded state, and thereby reducing the influence of the secondary second body environment in the folded state on the performance of the first body antenna, thereby improving the antenna performance of the folding terminal when it is in the folded state. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG1 is a schematic structural diagram of an antenna system provided in an embodiment of the present application.

[0016] FIG2 is a schematic structural diagram of another antenna system provided in an embodiment of the present application.

[0017] FIG3 is a schematic diagram of a three-dimensional structure of an antenna system in related art.

[0018] FIG4 is a schematic diagram of a three-dimensional structure of an antenna system provided in an embodiment of the present application.

[0019] FIG5 is a schematic structural diagram of the first antenna tuning unit 31 provided in an embodiment of the present application.

[0020] FIG6 is a schematic structural diagram of the second antenna tuning unit 32 provided in an embodiment of the present application.

[0021] FIG7 is a comparison curve of S parameters of an antenna system provided in an embodiment of the present application and a first antenna in a traditional antenna system in the B39 / B41 frequency band.

[0022] FIG8A is a comparison curve of the radiation efficiency of an antenna system provided in an embodiment of the present application and the first antenna in a traditional antenna system in the B39 frequency band.

[0023] FIG8B is a comparison curve of the radiation efficiency of the first antenna in the B41 frequency band between an antenna system provided in an embodiment of the present application and a traditional antenna system.

[0024] FIG9 is a schematic diagram of the three-dimensional structure of another antenna system provided in an embodiment of the present application.

[0025] FIG10 is a simplified schematic diagram of the cross-sectional electric field distribution in the first direction of the B41 frequency band of the first antenna of an antenna system provided by an embodiment of the present application in a folded state.

[0026] FIG11 is a schematic structural diagram of another antenna system provided in an embodiment of the present application.

[0027] FIG12 is a comparison curve of the radiation efficiency of the first antenna of an antenna system provided in an embodiment of the present application in the B3 frequency band.

[0028] FIG13A is a partial schematic diagram of current distribution of a first antenna in an antenna system provided in an embodiment of the present application at 1.8 GHz in the B3 frequency band.

[0029] FIG13B is a partial schematic diagram of the current distribution of the first antenna in the conventional antenna system of the present application at 1.8 GHz in the B3 frequency band.

[0030] FIG14 is a schematic structural diagram of another antenna system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0032] The terms "first," "second," and so on, in the specification and claims of this application are used to distinguish similar objects, not to describe a specific order or precedence. It should be understood that such terms are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein. Furthermore, the objects distinguished by "first," "second," and so on generally refer to a class and do not limit the number of objects. For example, the first object can be one or more. Furthermore, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the connected objects are in an "or" relationship.

[0033] In order to improve the antenna performance of a foldable terminal in a folded state, an embodiment of the present application provides a foldable terminal. The foldable terminal may include but is not limited to any electronic device such as a smartphone, a tablet computer, a smart wearable device, etc.

[0034] A foldable terminal provided by an embodiment of the present application is described in detail below with reference to the accompanying drawings through specific embodiments and application scenarios.

[0035] Figure 1 is a view of the foldable terminal in the unfolded state, wherein the left side of the hinge 100 is the back view of the main screen, and the right side of the hinge 100 is the front view of the sub-screen. The same is true for Figures 2, 11, and 14, which will not be repeated below.

[0036] As shown in FIG1 , an embodiment of the present application provides an antenna system, which may include: a first antenna 01 and a first antenna tuning unit 31 .

[0037] It should be noted that, in the embodiment of the present application, the first antenna may be any antenna of the foldable terminal. For example, the first antenna may be one of Ant1, Ant2, Ant3, and Ant10 mentioned below.

[0038] Specifically, the first antenna may include but is not limited to the following:

[0039] Low-frequency (LB) transceiver antenna;

[0040] Middle high band (MHB) transceiver antenna;

[0041] Ultra-high-band (UHB) transceiver antenna.

[0042] More specifically, the frequency band of the first antenna may include but is not limited to one of the following:

[0043] B1 / B3 / B39 / B40 / B41, such as the frequency band of Ant1 mentioned in this article;

[0044] N78 / wifi5G, such as the frequency band of Ant2 mentioned in this article;

[0045] N78 / 79, the frequency band of Ant2 mentioned in this article;

[0046] GPS L1, such as the frequency band of Ant3 mentioned in this article;

[0047] GPS L5, such as the frequency band of Ant10 mentioned in this article.

[0048] Generally speaking, as shown in Figure 1, since the main body 10 has a better environment and is more suitable for deploying antennas, the first body can be the main body 10 of the foldable terminal, and the second body can be the secondary body 20 of the foldable terminal. Of course, the reverse can also be true, with the first body being the secondary body 20 of the foldable terminal and the second body being the main body 10 of the foldable terminal.

[0049] The following description will be made by taking the first body as the main body 10 and the second body as the sub-body 20 as an example.

[0050] Referring to Figure 1, it can be seen that the first antenna 01 is arranged on the first frame branch 11 of the main body 10, and the first antenna 01 uses the first frame branch 11 as the radiation structure; one end of the first antenna tuning unit 31 is connected to the first position A′ of the second frame branch 21 in the secondary body 20, and the other end of the first antenna tuning unit 31 is grounded.

[0051] As an example, the first antenna tuning unit 31 may be grounded via the floor 23 in the sub-body 20 .

[0052] Among them, the main body 10 and the secondary body 20 are connected by a rotating shaft 100; the first frame branch 11 and the second frame branch 21 are symmetrical or approximately symmetrical about the rotating shaft 100; the first position A′ is the position on the second frame branch 21 where the distance from the current return position A of the first antenna 01 is less than a preset distance when the folding terminal is in a folded state; the first antenna tuning unit 31 is used to trigger the floor 23 to generate a current in a specified direction, so as to induce a current in the second frame branch 21 with the same direction as the current in the first antenna 01.

[0053] The first position A' is symmetrical or approximately symmetrical with the current return position A of the first antenna 01 about the rotation axis 100. In other words, the first position A' is located at the end of the second frame branch 21. It should be noted that the "end" here is not only the end of the physical structure, but also the position with high current and low electric field. In other words, this position is the high current return position, that is, the non-opening radiation area.

[0054] It can be understood that when the foldable terminal is in the folded state, the first antenna 01 located on the first frame branch 11 of the main body 10 will be affected by the second frame branch 21 and the screen of the secondary body 20. The electric field generated by the current in the first antenna 01 will induce the second frame branch 21, and a current will be formed in the second frame branch 21 in the opposite direction to the current in the first frame branch 11 (that is, the radiator of the first antenna 01), thereby generating energy coupling loss and degrading the performance of the first antenna 01.

[0055] The antenna system provided in the embodiment of the present application can trigger the floor 23 to generate a current in a specified direction by introducing a first antenna tuning unit 31 at a first position A′ on the second frame branch 21 that is symmetrical to the first frame branch 11 about the rotation axis 100, so as to induce a current in the second frame branch 21 with the same direction as the current in the first antenna 01, thereby increasing the proportion or intensity of the current in the same direction as the first frame branch 11 on the second frame branch 21 to offset the current in the opposite direction to the current in the first frame branch 11 that exists simultaneously on the second frame branch 21, thereby reducing the electric field energy coupling loss of the first antenna 01 in the folded state, and further reducing the influence of the secondary body 20 environment in the folded state on the antenna performance of the first antenna 01 in the main body 10, thereby improving the antenna performance of the folding terminal when it is in the folded state.

[0056] The structure and advantages of an antenna system provided by an embodiment of the present application are described in detail below with reference to FIG. 2 .

[0057] Figure 2 is a view of a foldable terminal in an unfolded state, showing a more detailed antenna system design scheme. As shown in Figure 2, an antenna system provided by an embodiment of the present application includes:

[0058] The first frame branch 11 and the third frame branch 12 on the main body 10, and the frame of the main body 10 are provided with fractures 1, 2, and 3;

[0059] The second frame branch 21 and the fourth frame branch 22 on the auxiliary body 20, and the frame of the auxiliary body 20 are provided with fractures 4, 5, and 6;

[0060] A first antenna tuning unit 31;

[0061] Axis (usually a hinge) 100;

[0062] a floor 13 on the main body 10 and a battery compartment area 14 in the main body 10;

[0063] A floor 23 on the sub-body 20 and a battery compartment area 24 in the sub-body 20 .

[0064] Generally, the floor panels 13 and 23 are both printed circuit boards (PCBs).

[0065] The main body 10 and the auxiliary body 20 are folded by rotating around the rotation axis 100. The slits 1 / 2 / 3 on the main body 10 are symmetrical with the slits 4 / 5 / 6 on the auxiliary body 20 before and after folding. The width of these slits is 1mm-4mm.

[0066] As shown in FIG. 2 , an antenna Ant1 (an example of a first antenna) is provided on the first frame branch 11 of the main body 10 , and Ant2 and Ant3 are further provided on the third frame branch 12 .

[0067] Ant1 is an MHB TRX antenna, whose feeding point is located at B, and the width BC from the break 2 is 1mm-4mm. It goes down to the ground through the metal connecting material at point A and returns to the floor 13, where the width of the metal connecting material at point A is 3mm-6mm; the AC branch (first frame branch 11) is the radiation structure of Ant1, and its length is 20mm-23mm (this length is generally one-quarter wavelength of its resonant frequency band).

[0068] Ant2's frequency bands include N78 / wifi5G or N78 / 79. Its feeding point is located at point E, the DE length is 1mm-2mm, and the DF length is 6mm-8mm.

[0069] The frequency band of Ant3 is GPS L1, its feeding point is located at point H, the HI length is 7mm-11mm, and the GI length is 19mm-23mm.

[0070] Ant2 and Ant3 are connected to the ground through capacitors C1 and C2 at points F and G on the third frame branch 12, respectively, and return to the floor 13, where the size of capacitor C1 is about 7.5pF-15pF, and the size of capacitor C2 is about 10pF-33pF. The use of capacitor return here is mainly to utilize the metal third frame branch 12 to suspend a compatible specific absorption rate sensor (SAR-sensor) to meet the SAR value in the relevant standards. The length of the third frame branch 12 is generally one-quarter the wavelength of its resonant frequency band.

[0071] As shown in Figure 2, the frame of the secondary body 20 is usually symmetrical with the frame of the main body 10 after folding, and a first antenna tuning unit 31 is provided on the second frame branch 21 of the secondary body 20. The first antenna tuning unit 31 is located at the first position A' of the second frame branch 21, and the first position A' is close to the break 4. The distance between the first position A' and the break 4 is 0mm-3mm. After folding, the first position A' is located near the return position A of Ant1. In other words, after folding, the distance between the first position A' and the return position A of Ant1 is less than the preset distance, for example, less than 1mm-3mm. Generally speaking, the length of the A'C' branch is 26mm-32mm (this length is generally less than one-quarter wavelength of the resonant frequency band of Ant1).

[0072] Among them, the first antenna tuning unit 31 is used to trigger the floor 23 in the secondary body 20 to generate a current in a specified direction, and the specified direction is the same as the current direction in the first frame branch 11 (the radiator of Ant1). After the first antenna tuning unit 31 is introduced into the antenna system provided in the embodiment of the present application, the proportion or intensity of the current in the same direction as that in the first frame branch 11 on the second frame branch 21 can be increased to offset the current in the opposite direction to the current in the first frame branch 11 that exists simultaneously on the second frame branch 21, thereby reducing the electric field energy coupling loss of Ant1 in the folded state, thereby reducing the impact of the secondary body 20 environment in the folded state on the antenna performance in the main body 10, and improving the performance of the antenna Ant1 when the folding terminal is in the folded state.

[0073] Optionally, an Ant 10 is provided on the fourth frame branch 22 of the secondary body 20. The frequency band of the Ant 10 is GPS L5, the feeding point D' thereof is close to the fracture 5, and the length of the D'E' branch is 34mm-38mm.

[0074] In order to more clearly understand the advantages of an antenna system provided by an embodiment of the present application, a brief introduction to a traditional antenna system is given below.

[0075] FIG3 is a schematic diagram of the three-dimensional structure of an antenna system in the related art. As shown in FIG3, in this antenna system, a second antenna tuning unit 32 is connected only at point B′ of the second frame branch 21 of the secondary body 20. The first position A′ is connected to the floor 23 via a metal connector 30. The second antenna tuning unit 32 adjusts the resonance generated by the second frame branch 21 to be lower than the resonance generated by the first frame branch 11, thereby helping to improve the antenna performance of Ant1 in the folded state. Because the second frame branch 21 and the first frame branch 11 are symmetrically arranged on the same side after folding and are close to each other, a strong reverse coupling current exists on the second frame branch 21. In fact, introducing the second antenna tuning unit 32 at position B′ near the fracture 5 can easily tune its auxiliary resonance point, but it is difficult to weaken the reverse current in the second frame branch 21, and thus cannot ensure that the electric field coupling of Ant1 is reduced to a minimum in the folded state.

[0076] Compared to the conventional antenna system shown in FIG3 , as shown in FIG4 , an antenna system provided in an embodiment of the present application further introduces a first antenna tuning unit 31. One end of the first antenna tuning unit 31 is connected to the first position A′ of the second frame branch 21 in the secondary body 20, and the other end of the first antenna tuning unit 31 is grounded through the floor 23 in the secondary body 20. The first position A′ is close to the slit 4, and the distance from the slit 4 is between 0 mm and 3 mm. After folding, the first position A′ is located near the ground-returning position A of Ant1.

[0077] It should be noted that the first antenna tuning unit 31 is different from the second antenna tuning unit 32. It not only simply adjusts the resonance generated by the secondary body 20, but also triggers the floor 23 to generate a current in a specified direction, so as to induce a current in the second frame branch 21 with the same direction as the current in Ant1, so that the proportion or intensity of the current in the same direction on the second frame branch 21 as the first frame branch 11 is increased to offset the current in the opposite direction of the current in the first frame branch 11 that exists on the second frame branch 21 at the same time, thereby reducing the electric field energy coupling loss of Ant1 in the folded state, thereby reducing the impact of the secondary body 20 environment in the folded state on the antenna performance in the main body 10, and improving the antenna performance of the folding terminal when it is in the folded state.

[0078] The first antenna tuning unit 31 includes multiple trigger circuits, wherein different trigger circuits are used to trigger the ground plane 23 to generate currents of different magnitudes in the specified direction to correspondingly improve the performance of Ant1 in different frequency bands. The multiple trigger circuits may include, but are not limited to, one or more of a resistance circuit, an inductance circuit, and a capacitance circuit.

[0079] Specifically, the first antenna tuning unit 31 can be a switch module including a multi-way trigger circuit, or a lumped component, such as an LC, including a multi-way trigger circuit. A lumped component is a passive component used in circuits that combines the functions of an inductor and a capacitor. LC is a common type of lumped component, where L represents the inductor and C represents the capacitor.

[0080] The following takes the first antenna tuning unit 31 as a switch module including a multi-channel trigger circuit as an example to explain how the first antenna tuning unit 31 triggers the floor 23 to generate current and correspondingly improves the antenna performance in which frequency band.

[0081] Assume that Ant1 is an MHB TRX. As shown in Figure 5 , the first antenna tuning unit 31 includes a first inductor circuit L10, a second inductor circuit L11, a first resistor circuit R1, and a first capacitor circuit C1 connected in parallel. In actual application, one end 310 of the first antenna tuning unit 31 is connected to the first position A′ in Figure 4 , and the other end 311 of the first antenna tuning unit 31 is connected to the floor 23 in Figure 4 .

[0082] As mentioned above, the first position A' is located at the end of the second frame branch 21. It should be noted that the "end" here is not only the end of the physical structure, but also the position with large current and small electric field, that is, the position where large current returns to the ground, that is, the non-opening radiation area.

[0083] As shown in Figure 5, by switching different inductance values, resistance values ​​or capacitance values ​​through the switch 1 in the first antenna tuning unit 31, the floor 23 can be triggered to generate currents of different sizes corresponding to different frequency bands of Ant1 in a specified direction. The changes in the strength of the current in the floor 23 are sensed on the second frame branch 21, thereby increasing the proportion or intensity of the current in the same direction as that in the first frame branch 11 on the frame branch.

[0084] As an example:

[0085] 1) The inductance adjustment range of the first inductor circuit L10 is between 2nH and 4nH. If the first antenna tuning unit 31 is switched to the first inductor circuit L10, the current generated by the first antenna tuning unit 31 triggering the ground plane 23 can improve the performance of the first antenna in the B3 / B39 frequency band;

[0086] 2) The inductance adjustment range of the second inductor circuit L11 is between 1nH and 3nH. If the first antenna tuning unit 31 is switched to the second inductor circuit L11, the current generated by the first antenna tuning unit 31 triggering the ground plane 23 can improve the performance of the first antenna in the B1 frequency band;

[0087] 3) The resistance adjustment range in the first resistance circuit R1 is above 0 ohm, and the capacitance adjustment range in the first capacitance circuit C1 is above 1 pF. If the first antenna tuning unit 31 is switched to the first resistance circuit R1 or the first capacitance circuit C1, the current generated by the first antenna tuning unit 31 triggering the floor 23 can improve the performance of the B40 / B41 frequency band of the first antenna.

[0088] From the above examples, it can be found that by switching different inductance values, resistance values ​​or capacitance values ​​through the switch 1 in the first antenna tuning unit 31, the floor 23 can be triggered to generate currents of different sizes corresponding to different frequency bands of Ant1 in a specified direction, thereby increasing the proportion or intensity of the current in the same direction as that in the first frame branch 11 on the second frame branch 21, thereby improving the performance of Ant1 in different frequency bands.

[0089] Optionally, an antenna system provided in an embodiment of the present application further includes: a second antenna tuning unit 32, one end of the second antenna tuning unit 32 is connected to point B' of the second frame branch 21, the length of point B' from the break 5 is 2mm-6mm, and the other end of the second antenna tuning unit 32 is grounded through the floor 23. The second antenna tuning unit 32 is used to adjust the resonance generated by the second frame branch 21 to be lower than the resonance generated by the first frame branch 11, or in other words, the second antenna tuning unit 32 is used to adjust the resonance generated by the second frame branch 21 so that the resonance generated by the second frame branch 21 falls in front of the resonance generated by the first frame branch 11. Introducing the second antenna tuning unit 32 in the antenna system provided in an embodiment of the present application can reduce the resonance generated by the second frame branch 21 on the secondary body 20, thereby achieving the purpose of assisting in improving the antenna performance of Ant1 in the folded state.

[0090] The second antenna tuning unit 32 may also be a switch module including a multi-channel trigger circuit, or the second antenna tuning unit 32 may also be a lumped element including a multi-channel trigger circuit, such as an LC.

[0091] The structure of the second antenna tuning unit 32 will be briefly described below by also taking the second antenna tuning unit 32 as a switch module including a multi-channel trigger circuit as an example.

[0092] As shown in FIG6 , the second antenna tuning unit 32 includes a third inductor circuit L1, a fourth inductor circuit L2, a fifth inductor circuit L3, and a second resistor circuit R0 connected in parallel. In actual application, one end 320 of the second antenna tuning unit 32 is connected to position B′ in FIG4 , and the other end 321 of the second antenna tuning unit 32 is connected to the floor 23 in FIG4 .

[0093] Generally speaking, the smaller the inductance / resistance value provided by the second antenna tuning unit 32 (the resistance can be cut to the limit of 0 ohms in the B41 frequency band), the higher the resonance generated by the second frame branch 21. This is conventional tuning and will not be described in detail.

[0094] The advantages of an antenna system provided in an embodiment of the present application are further described below by taking the B39 / B41 frequency band of Ant1 (an example of the first antenna) as an example.

[0095] Figure 7 is a comparison curve of the S parameters of an antenna system provided by an embodiment of the present application and the first antenna in a conventional antenna system in the B39 / B41 frequency band in the folded state. In Figure 7, the feed paths of the antenna system provided by the embodiment and Ant1 (an example of the first antenna) in the conventional antenna system are the same.

[0096] From the comparison curve of the S parameter (S11) in FIG7 , it can be seen that the antenna system provided in the embodiment of the present application can optimize the impedance, the resonance in the B39 / B41 frequency band is relatively deeper, and the impedance is closer to 50 ohms.

[0097] Figure 8A is a comparison curve of the radiation efficiency of the first antenna in the B39 frequency band of an antenna system provided by an embodiment of the present application and a conventional antenna system in the folded state. As can be seen from Figure 8A, in the folded state, the B39 peak efficiency of Ant1 (an example of the first antenna) in the antenna system provided by an embodiment of the present application can be improved by 0.7dB.

[0098] Figure 8B is a comparison curve of the radiation efficiency of the first antenna in the B41 frequency band of an antenna system provided by an embodiment of the present application and a conventional antenna system in the folded state. As can be seen from Figure 8B, in the folded state, the B41 peak efficiency of Ant1 (an example of the first antenna) in the antenna system provided by an embodiment of the present application can be improved by 1.1dB.

[0099] Table 1 shows the final antenna efficiency in each frequency band for an antenna system provided by an embodiment of the present application and Ant1 (an example of the first antenna) in a conventional antenna system in the folded state. As can be seen from Table 1, in the folded state, the average MHB performance of Ant1 (an example of the first antenna) in the antenna system provided by an embodiment of the present application can be improved by 0.8dB, with B41 improving by a maximum of 1.1dB.

[0100] Table 1

[0101] Taking B41 as an example, the following further analyzes the principle by which an antenna system provided in an embodiment of the present application can improve antenna performance.

[0102] Figure 9 is a schematic diagram of the three-dimensional structure of another antenna system provided in an embodiment of the present application. Figure 9 shows a schematic diagram of the local current distribution in the B41 frequency band of Ant1 (an example of the first antenna) of an antenna system provided in an embodiment of the present application when the screen is in a folded state. In Figure 9, the thickness of the arrow represents the intensity of the current.

[0103] As can be seen from Figure 9, by introducing the first antenna tuning unit 31 on the second frame branch 21, the floor 23 of the secondary body 20 can be triggered to generate a strong current, as shown by the dotted arrow. At the same time, a strong current Ia will be induced on the inner wall of the second frame branch 21. In addition, the AB segment on the first frame branch 11 in the main body 10, which is the radiation body of Ant1 (an example of the first antenna), also has a strong body current distribution. Since the gap 101 between the first frame branch 11 and the second frame branch 21 is small after folding, generally 1.5mm-2.5mm, there is a strong coupling between the two. Therefore, the current on the first frame branch 11 of Ant1 (an example of the first antenna) will also couple a completely opposite current Ib on the second frame branch 21, and the current Ib is mainly concentrated on the side close to the folding gap 101.

[0104] Generally, the stronger the reverse current Ib on the second frame branch 21, the more energy is coupled to it by the first frame branch 11. This is mainly manifested in increased electric field coupling and increased antenna energy loss. A portion of the energy radiation from Ant1 (an example of the first antenna) will be trapped in gap 101 and absorbed by the lossy metal or screen, resulting in a decrease in antenna radiation efficiency. If the reverse current Ib on the second frame branch 21 can be reduced, the energy coupling loss of Ant1 (an example of the first antenna) in the folded state can be reduced, thereby improving its radiation efficiency.

[0105] As can be seen from Figure 9, in an antenna system provided in an embodiment of the present application, a strong current Ia is triggered on the second frame branch 21 of the secondary body 20, and Ia is approximately opposite to Ib, and Ia is approximately in the same direction as the current on the radiating body AB (first frame branch 11) of Ant1 (an example of the first antenna). Among them, the strong current Ia is determined by the current on the floor 23, and the current on the floor 23 is triggered by the first antenna tuning unit 31 added to the second frame branch 21. Different from the reverse current of the second frame branch 21 mainly considered in the related art, the embodiment of the present application adopts a large current back-to-ground position loading method, which can trigger the current Ia between the gap between the second frame branch 21 and the floor 23, and the distribution of the current Ia is stronger than the coupling current on the second frame branch 21. Therefore, the embodiment of the present application can increase the proportion of the same-direction current on the second frame branch 21 in the secondary body 20, and at the same time offset part of the reverse current Ib, so it can weaken the energy of Ant1 (an example of the first antenna) B41 coupled to the secondary body 20 in the folded state, thereby achieving the purpose of improving the frequency band performance of Ant1 (an example of the first antenna) B41.

[0106] Figure 10 is a simplified schematic diagram of the cross-sectional electric field distribution in the first direction of the B41 frequency band of Ant1 (an example of the first antenna) in a folded state of an antenna system provided by an embodiment of the present application. In Figure 10, the thickness of the arrow represents the intensity of the current, 300 is the main screen, 302 is the sub-screen, and when the two are unfolded, a complete screen is formed. 303 is the battery back cover, 301 is the sub-screen back cover, and 101 is the gap between the main screen 300 and the sub-screen 302 after folding. The first direction is parallel to the long side of the sub-screen 301, the second direction is parallel to the short side of the sub-screen 301, and the third direction is perpendicular to the sub-screen 301. The cross-sectional electric field distribution diagram is a view in the first direction.

[0107] From the electric field distribution shown in Figure 10, there is a strong electric field coupling at the gap 101 between the folded first frame branch 11 and the second frame branch 21. According to the previous analysis, it is not difficult to understand that this is caused by a strong coupling reverse current Ib on the second frame branch 21; further analysis of the electric field distribution on the second frame branch 21, wherein the first arrow 41 represents the coupling electric field of the first frame branch 11 coupled to the second frame branch 21, and the second arrow 42 represents the electric field triggered by the first antenna tuning unit 31. It can be seen that the coupled electric field is completely opposite to the triggered electric field, so that the coupled electric field can be greatly offset by the triggered electric field. In particular, due to the presence of a strong unidirectional current Ia on the inner wall of the second frame branch 21, the coupled electric field caused by the first frame branch 11 is almost completely offset, so the distribution of the electric field strength is very weak.

[0108] From the above analysis, it can be concluded that an antenna system provided in an embodiment of the present application can effectively trigger the current on the side of its floor 23 by adding a tuning unit, the first antenna tuning unit 31, at the return position of the second frame branch 21 of the secondary body 20, thereby increasing the proportion or intensity of the unidirectional current on the second frame branch 21, thereby reducing the energy coupling loss of the electric field in the folded state, thereby reducing the impact of the secondary body 20 environment in the folded state on the antenna performance in the main body 10.

[0109] In addition, from the far field perspective, currents in the same direction are generated and superimposed on the main body 10 and the auxiliary body 20, thereby further improving the radiation efficiency of the first antenna, thereby achieving the purpose of improving the antenna performance.

[0110] FIG11 is a schematic diagram of the structure of another antenna system provided by an embodiment of the present application, showing the layout of three first antennas (Ant1, Ant2 and Ant3) at different positions on the main body 10 and the secondary body 20.

[0111] As shown in Figure 11, Ant1, Ant2 and Ant3 can be arranged on the frame branch 111, frame branch 112 and frame branch 113 of the main body 10, respectively, wherein these three frame branches are respectively located on the non-rotating axis side, top and bottom of the frame of the main body 10. In other words, the first antenna can be set on different branches of the frame of the main body 10, specifically, it can be set on the non-rotating axis side, top or bottom position of the frame of the main body 10. In other words, the first antenna can be set on the first frame branch 11 of the main body 10, wherein the first frame branch 11 can be any branch located on the top, bottom or non-rotating axis side of the frame of the main body 10, that is, the first frame branch 11 can be any branch of the frame branch 111, frame branch 112 and frame branch 113. In other words, the first antenna can be any antenna among Ant1, Ant2 and Ant3.

[0112] Specifically, as shown in FIG11 , Ant1 can be arranged on the frame branch 111, the feeding point of Ant1 is point B, the current return point is point A, and C is the end point. Accordingly, an antenna tuning unit 2111 can be added at point A′ on the frame branch 211 of the secondary body 20, and an antenna tuning unit 2112 can be added at point B′ on the frame branch 211 of the secondary body 20; Ant2 can be arranged on the frame branch 112, the feeding point of Ant2 is point B2, the current return point is point A2, and C2 is the end point. Accordingly, an antenna tuning unit 2112 can be added at point B′ on the frame branch 211 of the secondary body 20. An antenna tuning unit 2121 is added at point A2′ on the frame branch 212, and an antenna tuning unit 2122 is added at point B2′ on the frame branch 211 of the secondary body 20; Ant3 can be arranged on the frame branch 113, the feeding point of Ant3 is point B3, the current return point is point A3, and C3 is the end point - the antenna opening position. Accordingly, an antenna tuning unit 2131 can be added at point A3′ on the frame branch 213 of the secondary body 20, and an antenna tuning unit 2132 can be added at point B3′ on the frame branch 213 of the secondary body 20.

[0113] Among them, the antenna tuning unit 2111, the antenna tuning unit 2121 and the antenna tuning unit 2131 are the first antenna tuning unit mentioned above; the antenna tuning unit 2112, the antenna tuning unit 2122 and the antenna tuning unit 2132 are the second antenna tuning unit mentioned above.

[0114] It can be understood that the three arrangements of the first antenna in FIG11 can all improve the performance of the first antenna, as described in detail below.

[0115] Taking the first antenna as Ant1 and Ant1 as MHB as an example, the radiating body of Ant1 is the frame branch 111 of the main body (main body 10). The frame branch 111 is located on the non-rotating axis side of the main body, its feeding point is located at point B of the frame branch 111, the lower point is located at point A of the frame branch 111, the antenna opening is located at point C, and the antenna length of Ant1 is the length of the AC branch (this length is generally one-quarter wavelength of its resonant frequency band). After Ant1 is folded through the rotating shaft 101, the corresponding frame branch 211 of the secondary body (secondary body 20) is located on the non-rotating axis side of the secondary screen area and is approximately symmetrically distributed with the frame branch 111 of the main body after folding, wherein the end point C' of the fracture is aligned with C. The antenna tuning switch 2112 is arranged at position B' of the frame branch 211 of the secondary body. Note that the position of B' here does not need to be symmetrical with the position of point B on the frame branch 111 of the main body. The position of point B' can be adjusted according to actual debugging needs. Additionally, an antenna tuning unit 2111 is located at position A' on the secondary body's frame branch 211. Note that the position of A' does not need to be strictly symmetrical with point A on the primary body's frame branch 111. Generally, after folding, position A' is as close to point A as possible, ensuring that the length of the A'C' branch is no less than that of the AC branch. This ensures that the unidirectional current path excited on the A'C' branch is sufficiently long to offset more coupled reverse current.

[0116] As an example, assuming that an antenna tuning unit 2111 including an inductor circuit with an inductance of 1nH-2nH is added at point A′ on the frame branch 211 of the secondary body 20, the effect on the B3 frequency band of Ant1 is shown in Figure 12. Figure 12 is a comparative curve of the radiation efficiency of the first antenna of an antenna system provided in an embodiment of the present application in the B3 frequency band.

[0117] As can be seen from Figure 12, an antenna system provided by an embodiment of the present application can improve the radiation efficiency peak of Ant1 in the B3 band by up to 1.3dB compared with the traditional antenna system. Both schemes have an efficiency pit at 1.66GHz, and the position of this pit can be controlled by the antenna tuning switch 2112 at the B′ position of the frame branch 211 of the sub-body. Here, the efficiency pits of the two schemes are adjusted to the same position for comparison.

[0118] Figure 13A is a partial schematic diagram of the current distribution of the first antenna in an antenna system provided by an embodiment of the present application at 1.8 GHz in the B3 frequency band. Figure 13B is a partial schematic diagram of the current distribution of the first antenna in a conventional antenna system provided by the present application at 1.8 GHz in the B3 frequency band. In Figures 13A and 13B, the thickness of the arrows represents the current intensity, and the first antenna is Ant1.

[0119] As can be seen from Figure 13A, an antenna system provided in an embodiment of the present application can trigger a strong current I1 on the floor 23 of the secondary body, and at the same time induce a strong current Ia on the metal wall of the second frame branch 21 of the secondary body. This Ia is exactly opposite to the current Ib on the second frame branch 21 sensed by the first frame branch 11 of the main body, and is in the same direction as the current I0 on the first frame branch 11 of the main body. This can thereby achieve an increase in the proportion and intensity of the same-direction current on the second frame branch 21 of the secondary body in the folded state, reduce the loss of electric field coupling energy in the B3 frequency band in the folded state, and achieve the purpose of improving the antenna radiation efficiency.

[0120] As can be seen from Figure 13B, in the traditional solution, the intensity of the current I1 generated by the floor 23 of the secondary fuselage when triggered is relatively weak, and there is a reverse current. The current Ia induced on the metal wall of the second frame branch 21 is also relatively weak, and there is also a reverse current. Ultimately, the proportion of the reverse current of the second frame branch 21 in the folded state is much greater than the proportion of the unidirectional current (with the current I0 on the first frame branch 11 as a reference), resulting in an increase in the electric field energy coupling loss, so the antenna radiation efficiency will decrease.

[0121] As can be seen from the above description, in the embodiment of the present application, for antennas Ant1, Ant2, and Ant3 arranged at different positions on the main body, if the first antenna tuning unit is introduced at the corresponding position of the sub-body, the antenna performance can be improved. In addition, as can be seen from Figure 11, the antenna system provided in the embodiment of the present application can be flexibly arranged in a foldable terminal. The antenna layout is less restricted by the foldable screen device, and the antenna solution layout can be better adjusted according to the motherboard (floor) stacking.

[0122] FIG14 is a schematic structural diagram of another antenna system provided in an embodiment of the present application.

[0123] As shown in Figure 14, different from the embodiment described above, in an antenna system provided in the present application, the first antenna 01 can also be set on the second frame branch 21 of the secondary body 20, and accordingly, the first antenna tuning unit 31 can be correspondingly set on the first frame branch 11 of the main body 10.

[0124] Specifically, in the embodiment described above, the feed for the first antenna 01 is located on the frame branch of the main body 10, that is, the frame branch of the main body 10 serves as the frame radiating structure of the first antenna 01. In the embodiment shown in FIG14 , the feed for the first antenna 01 is located at point B′ of the second frame branch 21 of the secondary body 20, that is, the frame branch of the secondary body 20 serves as the radiating structure of the first antenna 01, connected to the ground via a metal reinforcement at point A′. The antenna length of the first antenna 01 is the length of the A′C′ branch, and is formed by a 1 / 4 IFA pattern of the A′C′ branch. When the first antenna 01 is folded by the hinge 101, the corresponding first frame branch 11 of the main body 10 is located on the side of the main screen area on the non-hinge side. After folding, the first frame branch 11 and the second frame branch 21 of the secondary body 20 are approximately symmetrically distributed, with the endpoints C′ and C of the fracture aligned. Correspondingly, the second antenna tuning unit 32 mentioned above is arranged at point B of the first frame branch 11 of the main body 10, and the first antenna tuning unit 31 mentioned above is arranged at point A. After such arrangement, by means of the first antenna tuning unit 31 arranged at the first frame branch 11 of the main body 10, a stronger current can be triggered on the floor side of the AC branch of the main body 10, thereby increasing the proportion and intensity of the unidirectional current on its AC branch (the unidirectional current is based on the current direction on the A′C′ branch of the radiation body structure of the folded first antenna 01 as a reference), which can effectively reduce the energy coupling loss of the electric field in the folded state, thereby reducing the influence of the main body environment in the folded state on the performance of the secondary body antenna, and improving the performance of the first antenna 01 arranged on the frame of the secondary body 20 in the folded state.

[0125] In addition, in Figure 14, in addition to placing the first antenna 01 on the non-rotating axis side frame of the secondary body 10, it can also be placed at the bottom and top of the frame of the secondary body 10. The first antenna tuning unit is correspondingly deployed at the corresponding position of the main body, and the same technical effect of improving the antenna performance can be achieved, which will not be described in detail.

[0126] In summary, the antenna system provided in Figure 14 shows that by placing the first antenna's feed on the branch of the secondary fuselage frame near the secondary screen, and adding the antenna tuning unit to the branch of the main fuselage frame, optimizing the antenna tuning unit can improve the proportion and intensity of the same-direction current on the branch of the main fuselage frame in the folded state, thereby reducing the impact of the main fuselage environment on the performance of the secondary fuselage antenna in the folded state, and improving the performance of the antenna arranged on the secondary fuselage frame in the folded state. In addition, the same technical effect can be achieved by placing the first antenna on the top or bottom of the secondary fuselage frame. Furthermore, placing the antenna on the secondary fuselage can further broaden the application scenarios of the antenna system provided in the embodiments of the present application.

[0127] The above describes an antenna system provided in an embodiment of the present application.

[0128] The embodiments of the present application also provide a foldable terminal, including an antenna system provided by the embodiments of the present application, which can improve the antenna performance in the folded state.

[0129] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0130] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), including a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0131] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. An antenna system, comprising: A first antenna (01) and a first antenna tuning unit (31); The first antenna (01) is arranged on a first frame branch (11) of the first body (10); One end of the first antenna tuning unit (31) is connected to a first position (A′) of a second frame branch (21) in the second body (20), and the other end of the first antenna tuning unit (31) is grounded; The first body (10) and the second body (20) are connected via a rotating shaft (100); the first frame branch (11) and the second frame branch (21) are symmetrical or approximately symmetrical about the rotating shaft (100); the first position (A′) is a position on the second frame branch (21) where the distance from the current return position (A) of the first antenna (01) to the ground is less than a preset distance when the first body (10) and the second body (20) are in a folded state; and the first antenna tuning unit (31) is used to trigger the floor (23) to generate a current in a specified direction, so as to induce a current in the second frame branch (21) with the same direction as the current in the first frame branch (11).

2. The antenna system according to claim 1, wherein: The first position (A′) and the current return position (A) are symmetrical about the rotation axis (100).

3. The antenna system according to claim 1, wherein: The first antenna tuning unit (31) comprises a multi-channel trigger circuit, wherein: Different trigger circuits in the first antenna tuning unit are used to trigger the floor (23) to generate currents of different magnitudes in the specified direction.

4. The antenna system according to claim 3, wherein: The trigger circuit includes one of the following: Resistor circuit; Inductive circuits; Capacitor circuit.

5. The antenna system according to claim 4, wherein: The first antenna is a medium-high frequency MHB transceiver antenna, and the first antenna tuning unit (31) comprises a first inductance circuit (L10), a second inductance circuit (L11), a first resistance circuit (R1) and a first capacitance circuit (C1) connected in parallel, wherein: The inductance adjustment range of the first inductance circuit (L10) is between 2nH and 4nH; The inductance adjustment range of the second inductance circuit (L11) is between 1nH and 3nH; The resistance adjustment range of the first resistance circuit (R1) is above 0 ohm; The capacitance adjustment range of the first capacitance circuit (C1) is above 1 pF.

6. The antenna system according to claim 1, wherein: The first frame branch (11) comprises any frame branch located at the top, bottom and non-rotating axis side of the frame of the first body (10).

7. The antenna system according to claim 1, wherein: The first antenna includes one of the following: Low frequency LB transceiver antenna; Medium and high frequency MHB transceiver antenna; Ultra-high frequency UHB transceiver antenna.

8. The antenna system according to claim 7, wherein: The frequency band of the first antenna specifically includes one of the following: B1 / B3 / B39 / B40 / B41; N78 / wifi5G; N78 / 79； GPS L1; GPS L5.

9. The antenna system according to any one of claims 1 to 8, wherein: The first body (10) is a main body of the foldable terminal, and the second body (20) is a secondary body of the foldable terminal; or, The first body (10) is a secondary body of the foldable terminal, and the second body (20) is a main body of the foldable terminal.

10. The antenna system according to any one of claims 1 to 8, wherein: The antenna system further comprises: a second antenna tuning unit (32); One end of the second antenna tuning unit (32) is connected to the second position (B′) of the second frame branch (21), and the other end of the second antenna tuning unit (32) is grounded, wherein the second antenna tuning unit (32) is used to adjust the resonance generated by the second frame branch (21) to be lower than the resonance generated by the first frame branch (11).

11. A foldable terminal, comprising: The antenna system according to any one of claims 1 to 10.

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