Balun antenna unit and terminal equipment

Abstract

This application provides a balun antenna element and a terminal device, which can be applied in the field of antenna technology. The balun antenna element includes: a first balun antenna disposed inside a first side of a base of the terminal device; and a second balun antenna disposed inside a second side of a base, wherein the first side and the second side are adjacent sides of the base; wherein the length direction of the first balun antenna is perpendicular to the length direction of the second balun antenna; both the first balun antenna and the second balun antenna are disposed in the non-grounded area of ​​the base, and the radiators of the first balun antenna and the second balun antenna are respectively spaced apart from the mounting surface of the base.

Description

Technical Field

[0001] This application relates to the field of antenna technology, and in particular to a balun antenna element and terminal device. Background Technology

[0002] As wireless communication systems place increasingly higher demands on antenna performance, antenna design faces more stringent challenges in terms of cost control and performance improvement. However, existing antenna technologies still suffer from numerous drawbacks. For example, while possessing good performance, antennas often suffer from high design costs and layout limitations. Furthermore, when covering a wide frequency band, antennas can cause electromagnetic interference and frequency shift, leading to instability. Therefore, it is difficult for antenna designs in existing technologies to simultaneously achieve high performance, low design cost, high isolation, high stability, and low SAR (Specific Absorption Rate) risk. Summary of the Invention

[0003] In view of the above problems, this application provides a balun antenna unit and a terminal device.

[0004] According to a first aspect of this application, a balun antenna unit is provided, comprising: a first balun antenna disposed inside a first side of a base of a terminal device; and a second balun antenna disposed inside a second side of the base, wherein the first side and the second side are adjacent sides of the base; wherein the length direction of the first balun antenna and the length direction of the second balun antenna are perpendicular; both the first balun antenna and the second balun antenna are disposed in a non-grounded area of ​​the base, and the radiators of the first balun antenna and the second balun antenna are respectively spaced apart from the mounting surface of the base.

[0005] According to an embodiment of this application, both the first balun antenna and the second balun antenna include a main radiating stub and a balun stub. The main radiating stub includes a first radiating arm and a second radiating arm. A first feed point is provided on the first radiating arm and is electrically connected to the outer conductor of the coaxial cable. A second feed point is provided on the second radiating arm and is electrically connected to the inner conductor of the coaxial cable. The two ends of the balun stub are respectively provided at the first feed point and the second feed point to form a short-circuit stub.

[0006] According to an embodiment of this application, the balun stub of the balun antenna is configured to be 1 / 4 of the wavelength corresponding to the operating center frequency of the balun antenna, wherein the balun antenna is either the first balun antenna or the second balun antenna.

[0007] According to an embodiment of this application, the aforementioned Baron branch is embedded into the aforementioned main radiating branch and integrated with the aforementioned main radiating branch to form a radiator.

[0008] According to the embodiments of this application, both the first radiating arm and the second radiating arm have a bending structure. The bending structure of the first radiating arm is configured as either a U-shaped structure or an L-shaped structure, and the bending structure of the second radiating arm is configured as either a U-shaped structure or an L-shaped structure.

[0009] According to an embodiment of this application, the bending structure includes a first segment and a second segment. The first segment is parallel to the length direction of the balun antenna, and the second segment is disposed in the inner region of the first segment in the width direction of the balun antenna.

[0010] According to an embodiment of this application, the effective height of the radiated electric field of the first balun antenna is the same as the length of the first balun antenna, and the effective height of the radiated electric field of the second balun antenna is the same as the length of the second balun antenna.

[0011] According to an embodiment of this application, the sum of the bending lengths of the second segments of the first radiating arm and the second radiating arm in the first balun antenna is matched with the difference between the physical length of the main radiating segment in the first balun antenna and the effective height of the radiated electric field of the first balun antenna; the sum of the bending lengths of the second segments of the first radiating arm and the second radiating arm in the second balun antenna is matched with the difference between the physical length of the main radiating segment in the second balun antenna and the effective height of the radiated electric field of the second balun antenna.

[0012] According to an embodiment of this application, the first radiating arm and the second radiating arm are spaced apart along the length direction of the balun antenna, the first segment of the first radiating arm and the first segment of the second radiating arm are collinear in the length direction of the balun antenna, and the physical lengths of the first radiating arm and the second radiating arm are the same.

[0013] A second aspect of this application provides a terminal device, which includes the aforementioned balun antenna element disposed on the base of the terminal device.

[0014] According to the balun antenna unit provided in this application, the first and second balun antennas are located in the non-grounded area of ​​the terminal equipment's base, reducing electrical connections with the metal casing. Furthermore, the radiators of both the first and second balun antennas are spaced apart from the mounting surface of the base, thus preventing interference caused by current flowing through the ground loop. Based on the ungrounded design of the first and second balun antennas, there is no need to use grounding copper or aluminum foil or other metal grounding layers, saving antenna development and design costs. The ungrounded design also allows the first and second balun antennas to be placed in suitable locations on the base, improving antenna layout flexibility. Simultaneously, the first and second balun antennas are placed vertically on the base to achieve dual polarization, further improving antenna directivity and coverage performance. Attached Figure Description

[0015] Figure 1 A schematic diagram of a PIFA antenna in the related art according to an embodiment of this application is shown;

[0016] Figure 2 A schematic diagram of a balun antenna element according to an embodiment of this application is shown.

[0017] Figure 3 A schematic diagram of the structure of a balun antenna according to an embodiment of this application is shown.

[0018] Figure 4 This schematically illustrates a simulation result of the surface current distribution of an antenna without balun stubs according to an embodiment of this application;

[0019] Figure 5 This schematically illustrates a simulation result of the surface current distribution of an antenna with balun stubs according to an embodiment of this application;

[0020] Figure 6 The illustration shows a schematic diagram of an antenna according to an embodiment of this application under different cable routing scenarios;

[0021] Figure 7 The schematic diagram illustrates the S11 parameters of an antenna without balun stubs according to an embodiment of this application under different cable routing scenarios;

[0022] Figure 8 The schematic diagram illustrates the S11 parameters of a balun antenna with a balun structure according to an embodiment of this application under different cable routing scenarios;

[0023] Figure 9 This schematic diagram illustrates a comparison of S11 parameter simulation results for antennas with and without balun stubs according to embodiments of this application.

[0024] Figure 10 A schematic diagram of a bending structure according to an embodiment of this application is shown;

[0025] Figure 11 This illustration schematically shows a diagram illustrating the setting principle of a bending structure according to an embodiment of this application;

[0026] Figure 12 The diagram illustrates different bending lengths in a balun antenna according to an embodiment of this application.

[0027] Figure 13 The schematic diagram illustrates the peak gain of balun antennas with different bending lengths according to embodiments of this application;

[0028] Figure 14 This illustration shows a comparison of the simulation results of the S21 parameters of a balun antenna and a PIFA antenna under the same conditions according to an embodiment of this application.

[0029] Figure 15 A schematic diagram illustrating the surface current distribution of a balun antenna element according to an embodiment of this application is shown.

[0030] Figure 16 A schematic diagram illustrating the surface electric field distribution of a balun antenna element according to an embodiment of this application is shown.

[0031] Figure 17 A schematic diagram illustrating the surface current distribution of a PIFA antenna according to an embodiment of this application is shown.

[0032] Figure 18 A schematic diagram illustrating the surface electric field distribution of a PIFA antenna according to an embodiment of this application is shown.

[0033] Figure 19 The schematic diagram illustrates the dual-polarization simulation results of a balun antenna element according to an embodiment of this application;

[0034] Figure 20 This schematic diagram illustrates a comparison of gain simulation results between a single-polarization horizontal distribution and a dual-polarization orthogonal distribution according to an embodiment of this application.

[0035] Figure 21 The diagram illustrates the S21 parameters between the first balun antenna and the second balun antenna in the open-circuit condition according to an embodiment of this application.

[0036] Figure 22 The diagram illustrates the S21 parameters between the first balun antenna and the second balun antenna under short-circuit conditions according to an embodiment of this application.

[0037] Figure 23 The radiation pattern of a balun antenna element at 2.45 GHz is schematically shown according to an embodiment of this application;

[0038] Figure 24 The radiation pattern of a balun antenna element at 5.47 GHz is schematically shown according to an embodiment of this application;

[0039] Figure 25 The radiation pattern of a balun antenna element at 6.525 GHz is schematically shown according to an embodiment of this application. Detailed Implementation

[0040] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0041] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0042] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0043] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0044] In the process of developing this application, it was discovered that while PIFA (Planar Inverted-F Antenna) antennas possess good performance, their additional grounding system increases design costs; furthermore, their grounding method can easily lead to limitations in system layout; simultaneously, the common grounding configuration of PIFA antennas means that current return between antennas affects isolation, thus impacting the overall antenna system performance. Dipole antennas, although requiring no grounding, are relatively large in size when covering a wide frequency band; furthermore, current from dipole antennas can easily flow back to the cable, causing electromagnetic interference and frequency shift, leading to antenna instability; dipole antennas also have a high peak gain, resulting in a greater SAR risk. While dual-polarized antennas offer advantages such as good coverage, high spectral efficiency, and strong anti-interference capabilities, there is still room for improvement in cost, stability, and size in related technologies.

[0045] Therefore, embodiments of this application provide a balun antenna element that simultaneously achieves high performance, low design cost, high isolation, high stability, and low SAR risk.

[0046] Figure 1 A schematic diagram of a PIFA antenna in the related art according to an embodiment of this application is shown.

[0047] like Figure 1 As shown, a PIFA antenna 110 and a PIFA antenna 120 are provided on the base 100. The PIFA antenna 110 transmits signals through a cable 111, and the PIFA antenna 120 transmits signals through a cable 121. The design of the PIFA antenna 110 requires copper foil 112 and aluminum foil 113, and the design of the PIFA antenna 120 requires copper foil 122 and aluminum foil 123.

[0048] In one embodiment, in the PIFA antenna, copper foil serves as the antenna's radiating conductor to ensure stable electrical performance; aluminum foil serves as a shielding material to suppress electromagnetic interference and as an auxiliary grounding material to increase the grounding area by utilizing its conductivity.

[0049] The PIFA antenna is mounted on the base of the device. Figure 1 The PIFA antennas 110 and 120 shown are only used to illustrate their positional relationship with the copper foil, aluminum foil, and cable, and do not directly show the specific structure of the PIFA antennas.

[0050] Figure 2 A schematic diagram of a balun antenna element according to an embodiment of this application is shown.

[0051] like Figure 2As shown, the balun antenna element includes a first balun antenna 210 and a second balun antenna 220.

[0052] According to an embodiment of this application, a first balun antenna 210 is disposed inside the first side of the base 200 of the terminal device; a second balun antenna 220 is disposed inside the second side of the base 200, wherein the first side and the second side are adjacent sides of the base. The first balun antenna 210 transmits signals via cable 211, and the second balun antenna 220 transmits signals via cable 221.

[0053] In one embodiment, the length direction of the first balun antenna 210 is perpendicular to the length direction of the second balun antenna 220. Specifically, in Figure 2 The angle between the direction indicated by arrow X and the direction indicated by arrow Y is 90°. Therefore, the length direction of the first balun antenna 210 can be the direction indicated by arrow Y, and the length direction of the second balun antenna 220 can be the direction indicated by arrow X. Figure 2 The shape of the base 200 is only an illustrative embodiment. The first side of the base 200 may be parallel to the length direction of the first balun antenna 210, or it may not be parallel to the length direction of the first balun antenna 210. The second side of the base 200 may be parallel to the length direction of the second balun antenna 220, or it may not be parallel to the length direction of the second balun antenna 220.

[0054] Based on this, the first balun antenna 210 and the second balun antenna 220 are vertically placed on the base 200 of the terminal device. The first balun antenna 210 can be placed as an Aux (auxiliary) antenna along the direction indicated by arrow Y to achieve vertical polarization; the second balun antenna 220 can be placed as a Main antenna along the direction indicated by arrow X to achieve horizontal polarization. Thus, the balun antenna element adopts an orthogonal dual-polarization design.

[0055] According to an embodiment of this application, the first balun antenna 210 and the second balun antenna 220 are specifically disposed on the mounting surface 230 of the base 200. Furthermore, both the first balun antenna 210 and the second balun antenna 220 are disposed in the non-grounded area of ​​the base 200, that is, the first balun antenna 210 and the second balun antenna 220 are designed to be ungrounded.

[0056] The non-grounded area of ​​the base 200 refers to the area on the base 200 that does not have a grounding copper foil or other metal grounding layer, no metal structure, no metallized vias or metal traces.

[0057] For example, Figure 1 The area where the copper foil 112 and aluminum foil 113 are located is the grounding area of ​​the base.

[0058] In one embodiment, both the first balun antenna 210 and the second balun antenna 220 adopt a suspended antenna element design, that is, the radiators of the first balun antenna 210 and the second balun antenna 220 are respectively spaced apart from the mounting surface 230 of the base 200. Specifically, a certain gap is maintained between the radiators of the first balun antenna 210 and the second balun antenna 220 and the mounting surface 230, so that the radiators of the first balun antenna 210 and the second balun antenna 220 do not directly contact the mounting surface 230 of the base 200.

[0059] In one embodiment, the radiators of the first balun antenna 210 and the second balun antenna 220 can both be supported by insulating supports fixed on the base 200, so that the radiators of the first balun antenna 210 and the second balun antenna 220 are respectively spaced apart from the mounting surface 230 of the base 200.

[0060] in, Figure 2 The first balun antenna 210 and the second balun antenna 220 are only used to show the positional relationship between the first balun antenna 210 and the second balun antenna 220 and their positional relationship with the base 200, and do not directly show the specific structure of the first balun antenna 210 and the second balun antenna 220. Figure 2 The positions of the first balun antenna 210 and the second balun antenna 220 on the base 200 are merely illustrative embodiments. The first balun antenna 210 and the second balun antenna 220 should be placed vertically on the base 200.

[0061] In one embodiment, both the first balun antenna 210 and the second balun antenna 220 can be fabricated using PCB (Printed Circuit Board) etching technology and fixed to the non-grounded area of ​​the base 200 by an insulating support.

[0062] by Figure 1 Taking the PIFA antenna shown as an example, the design of a PIFA antenna requires the use of copper foil and aluminum foil materials, and... Figure 2 The balun antenna element shown does not require the use of copper foil and aluminum foil materials. Therefore, the balun antenna element of this application saves copper foil and aluminum foil materials, reducing material costs and assembly labor costs.

[0063] According to embodiments of this application, the first and second balun antennas in the balun antenna unit are disposed in the non-grounded area of ​​the base of the terminal device, reducing electrical connections with the metal housing. Furthermore, the radiators of both the first and second balun antennas are spaced apart from the mounting surface of the base, thus preventing interference caused by current flowing through the ground loop. Based on the ungrounded design of the first and second balun antennas, there is no need to use grounding copper or aluminum foil or other metal grounding layers, saving antenna development and design costs. The ungrounded design also allows the first and second balun antennas to be placed in suitable locations on the base, improving antenna layout flexibility. Simultaneously, the first and second balun antennas are placed vertically on the base to achieve dual polarization, further improving antenna directivity and coverage performance.

[0064] According to embodiments of this application, both the first balun antenna and the second balun antenna include a main radiating stub and a balun stub.

[0065] Figure 3 A schematic diagram of the structure of a balun antenna according to an embodiment of this application is shown.

[0066] Among them, the balun antenna can be either the first balun antenna or the first balun antenna.

[0067] like Figure 3 As shown, the balun antenna 300 includes a main radiating stub 310 and a balun stub 320.

[0068] According to an embodiment of this application, the main radiating stub 310 includes a first radiating arm 311 and a second radiating arm 312. A first feed point 331 is provided on the first radiating arm 311, and the first feed point 331 is electrically connected to the outer conductor 341 of the coaxial cable. A second feed point 332 is provided on the second radiating arm 312, and the second feed point 332 is electrically connected to the inner conductor 342 of the coaxial cable. The two ends of the balun stub 320 are respectively provided at the first feed point 331 and the second feed point 332 to form a short-circuit stub.

[0069] exist Figure 3 In this design, the length direction of the balun antenna 300 is horizontal, and the width direction is vertical. For example, the length of the balun antenna 300 can be set to 35mm, and the width can be set to 8.5mm. The length and width of the balun antenna 300 can be set as needed. Furthermore, the balun stub 320 in the balun antenna 300 serving as the first balun antenna on the base can, for example, face inwards towards the base, and the balun stub 320 in the balun antenna 300 serving as the second balun antenna can also, for example, face inwards towards the base.

[0070] In one embodiment, the inner conductor of the coaxial cable is the core of the coaxial cable, and the outer conductor of the coaxial cable is the shielding layer of the coaxial cable. The coaxial cable is used to feed the balun antenna.

[0071] Because the outer conductor of the coaxial cable is connected to the first feed point and the inner conductor is connected to the second feed point, current may flow back to the coaxial cable, especially to the outer surface of the outer conductor, thus disrupting the antenna's normal radiation performance. Therefore, the balun antenna of this application incorporates a balun stub, with its two ends positioned at the first and second feed points respectively to form a short-circuit stub. Specifically, when current flows through the first feed point 331, the balun stub 320 can shunt the current through a short-circuit effect, forcing the current to short-circuit to the radiator and suppressing current flow back to the coaxial cable. In other words, the balun stub in the balun antenna can serve as a current guiding channel.

[0072] Figure 4 The schematic diagram illustrates the simulation results of the surface current distribution of an antenna without balun stubs according to an embodiment of this application.

[0073] like Figure 4 As shown, the small arrows represent the current intensity (A / m) on the antenna surface, and the direction of the small arrows indicates the actual flow direction of the current on the antenna surface; the large arrows represent a simplified diagram of the main current path to highlight "current injection" and "abnormal backflow".

[0074] exist Figure 4 In this configuration, the antenna has a symmetrical radiating structure, while the coaxial cable is an asymmetrical transmission line. A potential difference exists between the inner and outer conductors of the coaxial cable, with the outer conductor serving as both the signal return path and ground. Therefore, without a balun stub, due to the feed mismatch between the balanced antenna and the unbalanced coaxial cable, the current injected into the antenna radiating arm through the feed point cannot form an ideal differential return current. Some of the current will excite the outer surface of the coaxial cable's outer conductor, forming a common-mode return current. This current can flow along the cable's outer surface towards the signal source, thus causing the cable to participate in parasitic radiation. The feed point corresponds to a high-current region.

[0075] Figure 5 The schematic diagram illustrates the simulation results of the surface current distribution of an antenna with balun stubs according to an embodiment of this application.

[0076] like Figure 5 As shown, due to the presence of the balun stub 510, when current flows through the antenna feed point, the balun stub diverts the current through the short-circuit effect, suppressing the current from flowing back to the cable.

[0077] In one embodiment, when a coaxial cable is used to transmit signals for an antenna, changes in the distance between the coaxial cable and the metal structure in the terminal device will alter the characteristic impedance of the cable and the distribution of the surrounding electromagnetic field, thereby disrupting the impedance matching of the antenna and ultimately leading to a decrease in antenna radiation efficiency or a deterioration in signal stability.

[0078] The metal in the terminal device can be, for example, the metal casing or metal parts of the terminal device.

[0079] Based on this, the balun stub in the balun antenna of this application can improve the stability of the antenna.

[0080] Figure 6 The illustration shows schematic diagrams of antennas according to embodiments of this application under different cable routing scenarios.

[0081] like Figure 6 As shown, antenna 610 is mounted on base 600. Antenna 610 can be a balun antenna with balun stubs, or it can be an antenna without balun stubs, i.e., antenna 610 has no balun stubs. Figure 3 The Baron branch 320 is shown.

[0082] exist Figure 6 In this configuration, antenna 610 can transmit signals via cable 620 under cable wiring 1, cable 610 can also transmit signals via cable 630 under cable wiring 2, and cable 610 can also transmit signals via cable 640 under cable wiring 3. Cable wiring 1 of cable 620 can represent being away from metal, cable wiring 2 of cable 630 can represent being close to metal, and cable wiring 3 of cable 640 can represent passing through metal.

[0083] Based on this, the S11 parameter of an antenna characterizes the reflection coefficient at the antenna port, reflecting the impedance matching degree between the antenna and the feed line (i.e., cable). Specifically, the smaller the S11 parameter, the less signal reflection at the antenna port and the better the impedance matching. When the cable position and the distance between the cable and the metal change, the smaller the change in the S11 parameter, the stronger the antenna's anti-interference capability and stability. Therefore, as shown in... Figure 6 Taking cable routing 1 to cable routing 3 as examples, the S11 parameters of antennas with and without balun stubs were tested under different cable routings.

[0084] Figure 7 The diagram illustrates the S11 parameters of an antenna without balun stubs according to an embodiment of this application under different cable routing scenarios.

[0085] like Figure 7As shown, the horizontal axis represents frequency (in GHz), ranging from 2 to 7.94, which covers the core operating frequency band of the WIFI antenna; the vertical axis represents the S11 parameter of the WIFI antenna (in dB). Figure 7 The figure shows the S11 parameters of the antenna without baluns as a function of frequency under cable routing 1 (without BL_cable routing1, cable routing 1 without baluns), cable routing 2 (without BL_cable routing2, cable routing 2 without baluns), and cable routing 3 (without BL_cable routing3, cable routing 3 without baluns).

[0086] Figure 8 The schematic diagram illustrates the S11 parameters of a balun antenna with a balun structure according to an embodiment of this application under different cable routing scenarios.

[0087] like Figure 8 As shown, the horizontal axis represents frequency (in GHz), and the range of the horizontal axis is 2GHz to 7.92GHz, which covers the core operating frequency band of the WIFI antenna; the vertical axis represents the S11 parameter of the WIFI antenna (in dB). Figure 8 The table shows the S11 parameters of antennas with balun branches under cable routing 1 (with BL_cable routing1, cable routing 1 with balun branches), cable routing 2 (with BL_cable routing2, cable routing 2 with balun branches), and cable routing 3 (with BL_cable routing3, cable routing 3 with balun branches) as a function of frequency.

[0088] Based on such Figure 7 and Figure 8 As shown, the balun antenna with balun stubs has the most stable S11 parameter under different cable routing scenarios, with little fluctuation in the S11 parameter and very stable antenna performance; while the antenna without balun stubs has extremely unstable S11 parameter under different cable routing scenarios, with huge fluctuations in the S11 parameter and extremely unstable antenna performance.

[0089] According to an embodiment of this application, the balun antenna includes a main radiating stub and a balun stub. The balun stub is disposed at the feed end of the main radiating stub. Specifically, both ends of the balun stub are electrically connected to the first feed point and the second feed point of the main radiating stub, respectively, to form a short-circuit stub and thus a current guiding channel. This allows the balun stub to divert the current through a short-circuit effect when current flows through the antenna feed points (the first feed point and the second feed point), forcing the current to short-circuit to the radiator and suppressing the current from flowing back to the cable. Therefore, the balun stub configuration improves the stability of the balun antenna and makes it unaffected by the cable layout.

[0090] According to an embodiment of this application, the branch length of the balun stub of the balun antenna is configured to be 1 / 4 of the wavelength corresponding to the operating center frequency of the balun antenna. The balun antenna is either a first balun antenna or a second balun antenna.

[0091] In one embodiment, the branch length of the Baron branch represents the physical length of the Baron branch unfolding.

[0092] For example, when the operating center frequency of the balun antenna is 2.45 GHz, the length of the balun stub can be 31 mm.

[0093] Specifically, the balun antenna operates in the WIFI 2.4GHz, 5GHz and 6GHz bands, which belong to the microwave and millimeter wave bands. In terms of its operating characteristics, 1 / 4 wavelength corresponds to a short circuit in the circuit. Therefore, the length of the balun stub is set to 1 / 4 of the wavelength corresponding to the operating center frequency of the balun antenna, so as to form a short-circuit stub at the first feed point and the second feed point.

[0094] According to an embodiment of this application, by setting the length of the balun stub to 1 / 4 of the wavelength corresponding to the operating center frequency of the balun antenna, the balun stub can be formed as a short-circuit stub to suppress current backflow into the cable, thereby improving the stability of the antenna.

[0095] According to an embodiment of this application, the Baron branch is embedded into the main radiating branch and integrated with the main radiating branch to form a radiator.

[0096] In one embodiment, the base is provided with such Figure 3 The first and second balun antennas shown in the diagram can fully utilize the radiation generated by the balun antenna itself by balancing the current distribution of the balun antenna itself, reducing dependence on the ground. The long arm (i.e. the main radiating stub) of the balun antenna radiates WIFI 2.4GHz. The current coupling of the balun stub in the balun antenna will generate high-frequency resonance, thereby effectively expanding the antenna bandwidth.

[0097] Figure 9 The illustration shows a comparison of the S11 parameter simulation results of an antenna with and without a balun stub according to an embodiment of this application.

[0098] like Figure 9 As shown, the horizontal axis represents Frequency (in GHz), and the vertical axis represents the S11 parameter (in dB). Figure 9 The figure shows the variation of S11 parameters with frequency under S1,1-with balun (antenna with balun stub) and S1,1-without balun (antenna without balun stub).

[0099] In one embodiment, in antenna engineering, the core criterion for determining whether an antenna "effectively covers" a certain frequency band is that the absolute value of the S11 parameter in that frequency band must be greater than 10dB (i.e., the S11 parameter is less than or equal to -10dB).

[0100] Based on this, from Figure 9 As can be seen, compared with an antenna without a balun stub, an antenna with a balun stub can generate high-frequency resonance through current coupling, thereby extending the antenna coverage frequency band from WIFI 2.4GHz to 5GHz and 6GHz (specifically 5.15GHz~7.125GHz) to meet the needs of multi-band communication.

[0101] According to an embodiment of this application, the balun stub is integrated into the main radiating stub, so that the balun stub not only acts as a balancer, but also as part of the antenna radiator, which resonates at high frequencies and widens the antenna's operating bandwidth.

[0102] Based on the above, the balun stub can adopt an embedded inner balun structure to directly embed the balun stub into the antenna. On the one hand, it acts as a short-circuit stub, short-circuiting the current flowing into the coaxial cable end of the antenna, preventing the coaxial cable from directly participating in the antenna operation and thus interfering with the overall antenna performance, such as the stability of the S11 parameter. In other words, the balun stub can act as a balancer. On the other hand, as part of the antenna radiator, the balun stub is directly coupled with the main radiating stub of the antenna to create the 6GHz resonance of the WIFI band, thus expanding the antenna bandwidth.

[0103] According to an embodiment of this application, both the first radiating arm and the second radiating arm have a bending structure. The bending structure of the first radiating arm is configured as either a U-shaped structure or an L-shaped structure, and the bending structure of the second radiating arm is configured as either a U-shaped structure or an L-shaped structure.

[0104] like Figure 3 As shown, the bending structure of the first radiating arm 311 is configured as a U-shaped structure, and the bending structure of the second radiating arm 312 is configured as a U-shaped structure.

[0105] According to embodiments of this application, by designing a bending structure, the length dimension of the balun antenna is reduced while maintaining the overall physical dimensions of the antenna (i.e., the physical unfolded length of the antenna remains unchanged). Based on this, since the peak gain of the antenna is related to the antenna size, the peak gain of the antenna is reduced to a certain extent.

[0106] According to an embodiment of this application, the bending structure includes a first segment and a second segment. The first segment is parallel to the length direction of the balun antenna, and the second segment is disposed in the inner region of the first segment in the width direction of the balun antenna.

[0107] Figure 10 A schematic diagram of a bending structure according to an embodiment of this application is shown.

[0108] like Figure 10 As shown, the bending structure of the first radiating arm 311 of the balun antenna includes a first stub segment 1011 and a second stub segment 1012, and the bending structure of the second radiating arm 312 of the second balun antenna includes a first stub segment 1021 and a second stub segment 1022.

[0109] exist Figure 10 In the example of the second balun antenna set in the horizontal direction of the base, the first branch segment 1011 of the first radiating arm 311 and the second branch segment 1021 of the second radiating arm 312 are parallel to the length direction of the balun antenna, that is, the first branch segment 1011 of the first radiating arm 311 and the second branch segment 1021 of the second radiating arm 312 are parallel to the direction indicated by the arrow X.

[0110] In one embodiment, the second branch segment is disposed within the inner region of the first branch segment. Figure 10 As shown in the example, the direction pointed to by arrow Y is the inner region of the first branch segment, and the opposite direction pointed to by arrow Y is the outer region of the first branch segment.

[0111] in, Figure 10 The directions indicated by the middle arrows X and Y are merely illustrative examples.

[0112] According to an embodiment of this application, if the second stub is located in the outer region of the first stub, the width of the balun antenna will increase, thereby increasing the antenna size. However, the second stub is located in the inner region of the first stub so as not to affect the width of the balun antenna.

[0113] According to an embodiment of this application, the effective height of the radiated electric field of the first balun antenna is the same as the length of the first balun antenna, and the effective height of the radiated electric field of the second balun antenna is the same as the length of the second balun antenna.

[0114] In one embodiment, the bending structure can be set using the principle of equivalent circle transformation.

[0115] Figure 11 The schematic diagram illustrates the setting principle of the bending structure according to an embodiment of this application.

[0116] like Figure 11 As shown, the principle of equivalent circular transformation mainly involves converting the radiated electric field of a balun antenna into a circular electric field. The diameter of this circular electric field is the effective height of the radiated electric field of the antenna, which is also the length of the antenna.

[0117] Based on this, by setting a bending structure on the antenna to adjust the radius of the equivalent circular electric field, the effective height of the entire radiated electric field can be controlled, thereby achieving the effect of controlling the radiated field strength of the balun antenna.

[0118] exist Figure 11 In this process, a bending structure is set on the antenna, that is, the bending length of the antenna is increased (such as changing the straight segment to an "L" or "U" shaped bend), thereby introducing reverse current and reducing the effective height of the radiated electric field, thereby reducing the antenna peak gain and antenna size.

[0119] Figure 12 The diagram illustrates different bending lengths in a balun antenna according to an embodiment of this application.

[0120] like Figure 12 As shown, by increasing the bending length of the balun antenna, the effective height of the radiated electric field of the balun antenna is reduced from 40mm to 35mm.

[0121] In one embodiment, taking the effective height of the radiated electric field of the balun antenna as 40 mm and 35 mm as examples, the peak gain of the balun antenna with different bending lengths was tested.

[0122] Figure 13 The schematic diagram illustrates the peak gain of balun antennas with different bending lengths according to embodiments of this application.

[0123] like Figure 13 As shown, the horizontal axis represents frequency (in MHz), and the vertical axis represents Aux Antenna H-plan PeakGain (peak gain of the auxiliary antenna in the horizontal plane, in dBi).

[0124] In one embodiment, a balun antenna with a length of 40 mm is used as the antenna with a short bend, and a balun antenna with a length of 35 mm is used as the antenna with a long bend. Based on this, in Figure 13 The peak gain of the short-bend antenna and the long-bend antenna at different frequencies, as well as the maximum gain limit (Spec(MAX)) required by the design specifications, are shown in the figure.

[0125] exist Figure 13 In the study, the peak gain of the antenna in the 2GHz (2.4GHz) band was significantly higher than that in the 5GHz / 6GHz (5150MHz~7125MHz) band, showing a decreasing trend with increasing frequency. This trend was particularly pronounced in antennas with long bends, where the peak gain in the 5GHz band was even lower than 0dBi, demonstrating the physical law that the peak gain of the antenna decreases with increasing frequency under the frequency doubling effect.

[0126] based on Figure 13 As shown, compared to a short-bent antenna, a long-bent antenna reduces the effective length of its radiated electric field by about 12.5% ​​and the antenna peak gain by about 1 dBi, greatly reducing the SAR risk (specific absorption rate risk) of the balun antenna; at the same time, the antenna size is shortened by 12.5% ​​(the antenna length is shortened from 40 mm to 35 mm), which is suitable for the needs of miniaturized equipment.

[0127] According to embodiments of this application, based on equivalent circular transformation, the radiated electric field of the balun antenna is equivalent to a circular electric field, making the effective height of the radiated electric field of the balun antenna equal to the length of the balun antenna. Therefore, by controlling the bending length of the balun antenna's bending structure, the effective height of the radiated electric field can be controlled, thereby controlling the balun antenna's radiated field strength. Based on this, by increasing the bending length of the balun antenna, the actual trace length of the balun antenna remains unchanged while increasing the reverse current and reducing the effective height of the radiated electric field. This effectively reduces the antenna's size (i.e., antenna length) and peak gain, thereby reducing the antenna's SAR risk value.

[0128] In one embodiment, by increasing the bending length of the balun antenna, the effective height of the radiated electric field can be reduced, thereby reducing the peak gain and SAR risk value of the antenna. However, if the bending length of the bending structure is too long, it will reduce the antenna efficiency. Therefore, in the actual design of the balun antenna, the bending length needs to be set according to the antenna performance requirements in order to reduce the peak gain and SAR risk value while ensuring antenna efficiency.

[0129] According to an embodiment of this application, the sum of the bending lengths of the second stubs of the first and second radiating arms in the first balun antenna is matched with the difference between the physical length of the main radiating stub in the first balun antenna and the effective height of the radiated electric field of the first balun antenna; the sum of the bending lengths of the second stubs of the first and second radiating arms in the second balun antenna is matched with the difference between the physical length of the main radiating stub in the second balun antenna and the effective height of the radiated electric field of the second balun antenna.

[0130] In one embodiment, based on Figure 10As shown, for the first balun antenna, the bending length of the second stub 1012 of the first radiating arm 311 is the physical unfolded length of the second stub 1012, and the bending length of the second stub 1022 of the second radiating arm 312 is the physical unfolded length of the second stub 1022. The physical length of the main radiating stub in the first balun antenna is the physical unfolded length of the main radiating stub, specifically, the sum of the physical unfolded lengths of the first radiating arm 311 and the second radiating arm 312.

[0131] Therefore, since the effective height of the radiated electric field of the first balun antenna is equal to the length of the first balun antenna, the sum of the bending lengths of the second segments of the first and second radiating arms can be determined to some extent based on the difference between the physical length of the main radiating stub and its effective height of the radiated electric field. Thus, by changing the bending length, the change in bending length can be determined based on the change in the effective height of the radiated electric field. Similarly, the second balun antenna will not be discussed further here.

[0132] According to an embodiment of this application, the bending length can be determined based on the difference between the physical length of the main radiating stub and the effective height of the electric field. Based on this, by increasing the bending length, the peak gain of the strip and the size of the balun antenna (i.e., the antenna length) can be reduced, thereby reducing the SAR risk value of the antenna.

[0133] According to an embodiment of this application, the first radiating arm and the second radiating arm are spaced apart along the length direction of the balun antenna, the first segment of the first radiating arm and the first segment of the second radiating arm are collinear in the length direction of the balun antenna, and the physical lengths of the first radiating arm and the second radiating arm are the same.

[0134] In one embodiment, such as Figure 10 As shown, the first radiating arm 311 and the second radiating arm 312 are spaced apart along the length of the balun antenna, meaning there is a gap between the first radiating arm 311 and the second radiating arm 312 along the length of the balun antenna. Based on this, when determining the bending length based on the physical length of the main radiating stub of the balun antenna and the effective height of the radiated electric field of the balun antenna, the gap between the first and second radiating arms along the length of the balun antenna is further considered.

[0135] In one embodiment, while the first branch segment 1011 of the first radiating arm 311 is parallel to the length direction of the balun antenna and the first branch segment 1021 of the second radiating arm 321 is parallel to the length direction of the balun antenna, the first branch segment 1011 of the first radiating arm 311 and the first branch segment 1021 of the second radiating arm 312 are also collinear in the length direction of the balun antenna, so as to avoid unnecessary increase in the size of the balun antenna (i.e., antenna width) due to the first branch segment 1011 and the first branch segment 1021 not being collinear.

[0136] In one embodiment, the main radiating stub of the balun antenna is similar to a dipole structure, with a symmetrical design, and the first radiating arm and the second radiating arm each have the same physical length, that is, the first radiating arm and the second radiating arm each have the same physical unfolded length.

[0137] According to the embodiments of this application, the first and second radiating arms of the main radiating branch adopt an approximately symmetrical design and have the same physical length, so as to ensure that the current distribution and radiation performance of the first and second radiating arms tend to be consistent, thereby giving the balun antenna a symmetrical radiation pattern and improving the stability and reliability of the antenna operation.

[0138] Based on the above, the balun antenna unit of this application includes a first balun antenna and a second balun antenna disposed on the base of the terminal device. Therefore, it is necessary to consider the degree of signal interference and coupling between the first balun antenna and the second balun antenna, that is, to measure the isolation between the first balun antenna and the second balun antenna to ensure that the mutual interference between the first balun antenna and the second balun antenna in the balun unit of this application is small.

[0139] Figure 14 The diagram illustrates a comparison of the simulation results of the S21 parameters of a balun antenna and a PIFA antenna under the same conditions, according to embodiments of this application.

[0140] like Figure 14 As shown, the horizontal axis represents frequency (in GHz), and the vertical axis represents the S21 parameter (in dB). In the antenna field, the S21 parameter measures the isolation between antennas; the isolation is equal to the absolute value of the S21 parameter, and a higher isolation value indicates better isolation. Figure 14 The diagram shows the relationship between the S21 parameters of the balun antenna (S2,1-BL) and the PIFA antenna (S2,1-PIFA) and the frequency.

[0141] based on Figure 14Taking the antenna's operating frequency of 2.45GHz as an example, the isolation of the balun antenna has been improved from 16.97dB of PIFA to 27.24dB, and the isolation throughout the entire WIFI band is above 25dB, completely avoiding the common ground current interference problem of PIFA.

[0142] Based on the above, the electromagnetic interference between the first balun antenna and the second balun antenna can also be intuitively reflected by the distribution of current and electric field on the antenna surface.

[0143] Figure 15 A schematic diagram illustrating the surface current distribution of a balun antenna element according to an embodiment of this application is shown.

[0144] like Figure 15 As shown, since neither the first nor the second balun antenna in the balun antenna unit has a grounding structure, the current does not flow back to ground.

[0145] Figure 16 A schematic diagram illustrating the surface electric field distribution of a balun antenna element according to an embodiment of this application is shown.

[0146] like Figure 16 As shown, the isolation effect between the first balun antenna and the second balun antenna is good.

[0147] Figure 17 A schematic diagram illustrating the surface current distribution of a PIFA antenna according to an embodiment of this application is shown.

[0148] like Figure 17 As shown, the PIFA antenna uses a common ground structure, with current flowing back to ground.

[0149] Figure 18 A schematic diagram illustrating the surface electric field distribution of a PIFA antenna according to an embodiment of this application is shown.

[0150] like Figure 18 As shown, the isolation between PIFA antennas is poor.

[0151] Therefore, since the first balun antenna and the second balun antenna in the balun antenna element of this application adopt a non-common ground design, the electromagnetic interference between the first balun antenna and the second balun antenna, especially the low-frequency interference caused by the dual antenna current returning to ground structure, is reduced, thereby improving the isolation between the first balun antenna and the second balun antenna.

[0152] Meanwhile, laptops have specific design requirements for Wi-Fi antennas. Therefore, gain simulation was performed on the balun antenna element of this application to ensure that the performance of the balun antenna element meets the design requirements for Wi-Fi antennas. The gain simulation results of the first balun antenna (Aux) are shown in Table 1 below.

[0153] Table 1

[0154]

[0155] In one embodiment, the simulation efficiency of the main antenna (Simulation_Efficiency_MAIN (plus line loss)) is determined based on the gain simulation results of the first balun antenna, which serves as the main antenna, according to Table 1. The antenna gain is a key indicator for measuring antenna efficiency; the higher the gain, the better the efficiency.

[0156] Table 1 shows the antenna gain at different bands / frequencys. Specifically, Table 1 shows the required 3D gain specifications (Gain Spec 3D, in dB) and the simulated H-plane average gain, H-plane peak gain, and antenna average gain of the first balun antenna.

[0157] In Table 1, the open circuits of H-Plane avg.Gain in the third column and H-Plane Peak Gain in the fourth column can refer to simulations performed on the reference plane of the antenna radiating element, representing only the radiation performance of the antenna itself; the open circuits of H-Plane average Gain in the sixth column and H-Plane Peak Gain in the seventh column can refer to simulations performed at the feed port.

[0158] In one embodiment, Table 1 shows the antenna gain simulation results and design requirements under open and short-circuit conditions. Simulations were also performed for the 802.11b / g / n / ax (2.4GHz band, 2400MHz–2500MHz), 802.11a / n / ac / ax (5GHz band, 5150MHz–5850MHz), and WIFI 6E (6GHz band, 5925MHz–7125MHz) frequency bands.

[0159] Based on this, the gain values ​​corresponding to the frequencies involved in Table 1 all meet the design requirements and exhibit stable performance under different protocol frequency bands.

[0160] In one embodiment, the gain simulation results of the second balun antenna (Main) can be shown in Table 2 below.

[0161] Table 2

[0162]

[0163] In one embodiment, the simulation efficiency (Simulation_Efficiency_Aux(plus line loss)) of the auxiliary antenna is determined based on the gain simulation results of the second balun antenna, which serves as the auxiliary antenna, using Table 2.

[0164] Table 2 shows the antenna gain at different bands / frequencys. It also shows the design requirements for 3D gain (Gain Spec 3D, in dB) and the simulated H-plane average gain, H-plane peak gain, and average antenna gain of the second balun antenna.

[0165] In one embodiment, Table 2 shows the antenna gain simulation results and design requirements under open and short-circuit conditions. Simulations were also performed for the 802.11b / g / n / ax (2.4GHz band, 2400MHz–2500MHz), 802.11a / n / ac / ax (5GHz band, 5150MHz–5850MHz), and WIFI 6E (6GHz band, 5925MHz–7125MHz) frequency bands.

[0166] Based on this, the gain values ​​corresponding to the frequencies involved in Table 2 all meet the design requirements and perform stably under different protocol frequency bands.

[0167] Based on the above, the balun antenna unit of this application achieves good performance, and its performance meets the design requirements of notebook computers for WIFI antenna performance.

[0168] According to embodiments of this application, the first and second balun antennas in the balun antenna element are placed vertically on the base to achieve orthogonal dual polarization. Based on this, simulation tests are performed on the balun antenna element to ensure that the balun antenna element of this application can achieve orthogonal dual polarization.

[0169] Figure 19 The schematic diagram illustrates the dual-polarization simulation results of a balun antenna element according to an embodiment of this application.

[0170] like Figure 19 As shown, the first balun antenna in the balun antenna element serves as the auxiliary antenna (Aux), and the second balun antenna serves as the main antenna (Main). Figure 19 The image shows the far-field orientation of the main antenna and the auxiliary antenna at 2.45 GHz. Figure 11D Results (farfield pattern / 2.45GHz) are used to represent the relationship between elevation angle (Theta, in degrees) and gain (dBi). Specifically, the gain distribution of the main antenna and auxiliary antenna in the horizontal and vertical directions is shown.

[0171] based on Figure 19 As shown, the balun antenna element of this application has stable radiation performance and meets the design requirements.

[0172] In one embodiment, the gain simulation results of single-polarization horizontal distribution and dual-polarization orthogonal distribution can be shown in Table 3 below, where the unit of gain is dBi.

[0173] Table 3

[0174]

[0175] Figure 20 The diagram illustrates a comparison of gain simulation results between a single-polarization horizontal distribution and a dual-polarization orthogonal distribution according to an embodiment of this application.

[0176] like Figure 20 As shown, the horizontal axis represents frequency, specifically, the frequencies on the horizontal axis correspond to the frequencies shown in Table 3; the vertical axis represents gain, in dBi. Figure 20 The figure shows the simulation results of H-plane average gain under single-polarization horizontal distribution and dual-polarization orthogonal distribution. Figure 20 The average gain at each frequency under both single-polarization horizontal and dual-polarization orthogonal distributions is shown in Table 3. Figure 20 The simulation results show that, based on the non-interference and complementary characteristics of orthogonally polarized electromagnetic waves, the H-Plane average-gain of the dual-polarized orthogonal balun antenna is improved by about 0.5 dBi, which improves the antenna directivity. Within the specified range, the directivity of the orthogonal dual-polarized balun antenna element at 5 GHz is significantly stronger than that of the single-polarized horizontally distributed antenna.

[0177] Therefore, the balun antenna element of this application utilizes the transmission line principle and adopts a 1 / 4 wavelength short-circuit stub structure to form the balun stub. The balun stub not only acts as a balancer but is also embedded in the main radiating stub. At this point, the balun stub is no longer an independent part of the antenna, nor is it achieved by designing a special coaxial cable. It is part of the antenna radiator, effectively overcoming the complexity of traditional balun designs and achieving integration with the antenna, resulting in a smaller antenna size. Furthermore, through the coupling effect between the balun stub and the main radiating stub, the high-frequency antenna bandwidth is effectively expanded. The balun stub is no longer just a simple balancer but also participates in the antenna's signal transmission and reception as part of the radiating body. Meanwhile, the balun antenna element adopts a dual-polarized orthogonal balun antenna configuration. While maintaining the good performance of the PIFA antenna, the structure does not require grounding, saving antenna design costs, improving antenna layout, and suppressing antenna current return to ground, thus improving isolation. The balun antenna adopts a special balun structure, which improves antenna stability and bandwidth. It also uses the equivalent circular transformation principle to reduce the antenna's peak-gain value, solving some of the defects of dipole antennas. Furthermore, the first and second balun antennas are orthogonally and vertically placed on the base to achieve dual polarization, further improving antenna performance.

[0178] Based on the foregoing, this application also discloses a terminal device. This terminal device includes, for example: Figures 2-3 The balun antenna element shown is disposed on the base of the terminal device.

[0179] The above content is based on the establishment of a simulation model of the balun antenna element and the antenna efficiency, gain, isolation, and radiation pattern obtained by testing the simulation model. However, since the balun antenna element is ultimately to be applied in a real environment, the antenna efficiency, gain, isolation, and radiation pattern of the balun antenna element are tested when the balun antenna element is placed on the base of the terminal device to determine whether the dual-polarized orthogonal balun antenna of this application meets the conventional requirements of WIFI antennas under the actual test environment.

[0180] In one embodiment, under the actual working environment of the balun antenna element, the gain simulation results of the first balun antenna (Aux) in the balun antenna element can be shown in Table 4 below.

[0181] Table 4

[0182]

[0183] In one embodiment, under the actual working environment of the balun antenna element, the gain simulation results of the second balun antenna (Main) in the balun antenna element can be shown in Table 5 below.

[0184] Table 5

[0185]

[0186] Figure 21 The diagram illustrates the S21 parameters between the first balun antenna and the second balun antenna in the open-circuit condition according to an embodiment of this application.

[0187] like Figure 21 As shown, the horizontal axis represents frequency (in GHz), with a range of 2 GHz to 8 GHz, and the vertical axis represents the S21 parameters (in dB). Figure 21 The diagram illustrates the variation of the S21 parameter between the first and second balun antennas with frequency when isolation is disconnected (with added line loss), where the isolation between the first and second balun antennas is the absolute value of the corresponding S21 parameter. Specifically, Figure 21 The S21 parameters between the first and second balun antennas are shown at 2.40 GHz, 2.45 GHz, 2.50 GHz, 5.15 GHz, 5.85 GHz, 6.15 GHz, and 7.125 GHz.

[0188] Among them, isolation disconnection means that the antenna feed port is not connected to a load and is in an open circuit state.

[0189] Figure 22 The diagram illustrates the S21 parameters between the first balun antenna and the second balun antenna under short-circuit conditions according to an embodiment of this application.

[0190] like Figure 22 As shown, the horizontal axis represents frequency (in GHz), with a range of 2 GHz to 8 GHz, and the vertical axis represents the S21 parameters (in dB). Figure 22 The diagram illustrates the variation of the S21 parameter between the first and second balun antennas with frequency under the condition of metal isolation (with added line loss), where the isolation between the first and second balun antennas is the absolute value of the corresponding S21 parameter. Specifically, Figure 22 The S21 parameters between the first and second balun antennas are shown at 2.40 GHz, 2.45 GHz, 2.50 GHz, 5.15 GHz, 5.85 GHz, 6.15 GHz, and 7.125 GHz.

[0191] Metal isolation closure refers to the antenna feed port being directly connected to ground through metal conduction, thus being in a short-circuit state.

[0192] In one embodiment, Figure 21 and Figure 22All results were obtained at an IFBW (Intermediate Frequency Bandwidth) of 70kHz.

[0193] Figure 23 The radiation pattern of a balun antenna element at 2.45 GHz is schematically shown according to an embodiment of this application.

[0194] like Figure 23 As shown, the first balun antenna in the balun antenna element serves as the auxiliary antenna (Aux), and the second balun antenna serves as the main antenna (Main). Figure 23 The diagram shows the radiation patterns of the main and auxiliary antennas at 2.45 GHz, illustrating the relationship between elevation angle (Theta, in degrees) and gain (dBi). Specifically, it shows the gain distribution of the main and auxiliary antennas in the horizontal and vertical directions.

[0195] In one embodiment, Figure 23 The following figures sequentially illustrate the far-field realized absolute gain abbreviated in the horizontal plane (XOY plane, Theta=90), the far-field realized absolute gain abbreviated in the XOZ plane (Phi=0), and the far-field realized absolute gain abbreviated in the YOZ plane (Phi=90).

[0196] Figure 24 The radiation pattern of a balun antenna element at 5.47 GHz is schematically shown according to an embodiment of this application.

[0197] like Figure 24 As shown, the first balun antenna in the balun antenna element serves as the auxiliary antenna (Aux), and the second balun antenna serves as the main antenna (Main). Figure 24 The diagram shows the radiation patterns of the main and auxiliary antennas at 5.47 GHz, illustrating the relationship between elevation angle (Theta, in degrees) and gain (dBi). Specifically, it shows the gain distribution of the main and auxiliary antennas in the horizontal and vertical directions.

[0198] In one embodiment, Figure 24 The following figures sequentially illustrate the far-field realized absolute gain abbreviated in the horizontal plane (XOY plane, Theta=90), the far-field realized absolute gain abbreviated in the XOZ plane (Phi=0), and the far-field realized absolute gain abbreviated in the YOZ plane (Phi=90).

[0199] Figure 25The radiation pattern of a balun antenna element at 6.525 GHz is schematically shown according to an embodiment of this application.

[0200] like Figure 25 As shown, the first balun antenna in the balun antenna element serves as the auxiliary antenna (Aux), and the second balun antenna serves as the main antenna (Main). Figure 25 The diagram shows the radiation patterns of the main and auxiliary antennas at 6.525 GHz, illustrating the relationship between elevation angle (Theta, in degrees) and gain (dBi). Specifically, it shows the gain distribution of the main and auxiliary antennas in the horizontal and vertical directions.

[0201] In one embodiment, Figure 25 The following figures sequentially illustrate the far-field realized absolute gain abbreviated in the horizontal plane (XOY plane, Theta=90), the far-field realized absolute gain abbreviated in the XOZ plane (Phi=0), and the far-field realized absolute gain abbreviated in the YOZ plane (Phi=90).

[0202] Based on the above, the test results for antenna efficiency and gain, antenna isolation, and antenna pattern show that the balun antenna element of this application also exhibited good antenna performance in the actual test environment, fully meeting the conventional requirements of WIFI antennas.

[0203] Those skilled in the art will understand that the features described in the various embodiments of this application can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this application. In particular, the features described in the various embodiments of this application can be combined and / or combined in various ways without departing from the spirit and teachings of this application. All such combinations and / or combinations fall within the scope of this application.

[0204] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of this application, those skilled in the art can make various substitutions and modifications, all of which should fall within the scope of this application.

Claims

1. A balun antenna element, characterized in that, include: The first balun antenna is located on the inner side of the first side of the base of the terminal device; The second balun antenna is disposed inside the second side of the base, and the first side and the second side are adjacent sides of the base; Wherein, the length direction of the first balun antenna is perpendicular to the length direction of the second balun antenna; Both the first balun antenna and the second balun antenna are disposed in the non-grounded area of ​​the base, and the radiators of the first balun antenna and the second balun antenna are respectively spaced apart from the mounting surface of the base.

2. The balun antenna element according to claim 1, characterized in that, Both the first and second balun antennas include a main radiating stub and a balun stub. The main radiating stub includes a first radiating arm and a second radiating arm. A first feed point is provided on the first radiating arm and is electrically connected to the outer conductor of the coaxial cable. A second feed point is provided on the second radiating arm and is electrically connected to the inner conductor of the coaxial cable. The two ends of the balun stub are respectively located at the first feed point and the second feed point to form a short-circuit stub.

3. The balun antenna element according to claim 2, characterized in that, The balun stub of the balun antenna is configured to be 1 / 4 of the wavelength corresponding to the operating center frequency of the balun antenna, wherein the balun antenna is either the first balun antenna or the second balun antenna.

4. The balun antenna element according to claim 2, characterized in that, The Baron branch is embedded into the main radiating branch and integrated with the main radiating branch to form a radiator.

5. The balun antenna element according to claim 3, characterized in that, Both the first radiating arm and the second radiating arm have a bending structure. The bending structure of the first radiating arm is configured as either a U-shaped structure or an L-shaped structure, and the bending structure of the second radiating arm is configured as either a U-shaped structure or an L-shaped structure.

6. The balun antenna element according to claim 5, characterized in that, The bending structure includes a first segment and a second segment. The first segment is parallel to the length direction of the balun antenna, and the second segment is disposed in the inner region of the first segment in the width direction of the balun antenna.

7. The balun antenna element according to claim 6, characterized in that, The effective height of the radiated electric field of the first balun antenna is the same as the length of the first balun antenna, and the effective height of the radiated electric field of the second balun antenna is the same as the length of the second balun antenna.

8. The balun antenna element according to claim 7, characterized in that, The sum of the bending lengths of the second stubs of the first and second radiating arms in the first balun antenna is matched with the difference between the physical length of the main radiating stub in the first balun antenna and the effective height of the radiated electric field of the first balun antenna. The sum of the bending lengths of the second stubs of the first and second radiating arms in the second balun antenna is matched with the difference between the physical length of the main radiating stub in the second balun antenna and the effective height of the radiated electric field of the second balun antenna.

9. The balun antenna element according to claim 6, characterized in that, The first radiating arm and the second radiating arm are spaced apart along the length direction of the balun antenna. The first segment of the first radiating arm and the first segment of the second radiating arm are collinear along the length direction of the balun antenna. The physical lengths of the first radiating arm and the second radiating arm are the same.

10. A terminal device, characterized in that, The terminal device includes a balun antenna unit as described in any one of claims 1 to 9, wherein the balun antenna unit is disposed on the base of the terminal device.

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