Transmission line structure, method for preparing transmission line structure and terminal device

Abstract

The embodiments of the present application relate to the technical field of high-frequency transmission lines, and provide a transmission line structure, a method for preparing the transmission line structure, and a terminal device. The transmission line structure includes a high-frequency transmission segment, an impedance matching segment, and a stripline segment. Among them, the high-frequency transmission segment is a transmission line that takes into account the advantages of both waveguide and microstrip structures, and can realize a high-performance high-frequency signal planar circuit. At the same time, it can transmit higher frequency signals with lower insertion loss and thinner thickness. The transmission line structure provided in the embodiments of the present application can meet the requirements of high-frequency signal transmission while having lower transmission loss. Moreover, compared with the traditional flexible circuit board transmission line, the thickness of the high-frequency transmission segment is thinner, and therefore, it is also convenient for the transmission line structure to be routed inside the terminal device, and the space occupied is smaller.

Description

Technical Field

[0001] The present application relates to the technical field of high-frequency transmission lines, and in particular to a transmission line structure, a method for preparing the transmission line structure, and a terminal device. Background Art

[0002] At present, the types and numbers of antennas in terminal devices are increasing. Usually, these antennas are arranged around the middle frame of the terminal device. Radio frequency signals need to be transmitted between the antenna modules on the main circuit board and the auxiliary circuit board, and between the antenna modules on the main circuit board and the frame.

[0003] The current transmission carriers and methods include the following: for example, using wired signal lines in the frame area, but the outer diameter of the wired signal line itself and the corresponding avoidance space required result in a large space being occupied, which is not conducive to increasing the battery capacity of the terminal device; or, using FPC (Flexible Printed Circuit) to connect between the battery compartment and the back cover of the terminal device, or between the battery compartment and the frame.

[0004] However, the FPC is used to transmit signals between the main circuit board and other small boards or antenna modules. The transmission signal frequency is generally below 15GHz, mainly due to the large high-frequency loss. In order to reduce the loss of high-frequency signals in the FPC segment, the general sampling method is to increase the thickness of the FPC stacking layer and use the stripline structure as a reference for the interlayer. Therefore, the current FPC structure cannot take into account the problem of reducing its thickness and transmitting high-frequency signals with lower loss. Summary of the invention

[0005] The embodiments of the present application provide a transmission line structure, a method for preparing the transmission line structure, and a terminal device, aiming to improve the technical problems that the thickness of the existing transmission line structure is difficult to reduce and the insertion loss of high-frequency signals is large.

[0006] To achieve the above purpose, the embodiment of the present application adopts the following technical solution:

[0007] In a first aspect, the present application provides a transmission line structure, including a high-frequency transmission segment, an impedance matching segment, and a stripline segment.

[0008] Among them, the high-frequency transmission section is a transmission line that combines the advantages of waveguide and microstrip structures. It can realize high-performance high-frequency signal planar circuits. At the same time, it can transmit higher frequency signals with less insertion loss and thinner thickness.

[0009] Specifically, the high-frequency transmission section includes a dielectric substrate, a first conductive layer and a second conductive layer respectively arranged on opposite sides of the dielectric substrate, and a plurality of conductive tubes. The opposite sides of the dielectric substrate refer to the top surface and the bottom surface of the dielectric substrate. It can be understood that the first conductive layer is arranged on the top surface of the dielectric substrate, and the second conductive layer is arranged on the bottom surface of the dielectric substrate. Each conductive tube is penetrated through the first conductive layer, the dielectric substrate, and the second conductive layer, and one end of the conductive tube is electrically connected to the first conductive layer, and the other end of the conductive tube is electrically connected to the second conductive layer, and each conductive tube is divided into two groups and is respectively located on the opposite edge sides of the first conductive layer. Each conductive tube in the same group is arranged at intervals along the signal transmission direction, and corresponds to each conductive tube in the other group one by one. Here, the two groups of conductive tubes, the first conductive layer, and the second conductive layer enclose a receiving cavity, so that the electromagnetic wave is confined between the first conductive layer, the second conductive layer, and each conductive tube, and the field is transmitted in the dielectric substrate in a waveguide manner.

[0010] The impedance matching section is arranged at two opposite ends of the first conductive layer along the signal transmission direction.

[0011] The stripline segments are arranged at two opposite ends of the first conductive layer along the signal transmission direction and are placed on the dielectric substrate. The stripline segments are connected to the first conductive layer through corresponding impedance matching segments.

[0012] Here, the impedance matching segment is used to achieve impedance connection between the stripline segment and the high-frequency transmission segment to ensure impedance matching. The stripline segment is used to make electrical connections with the connection points of the circuit board. The stripline segment can be composed of at least one dielectric layer and a metal layer, the bottom dielectric layer is placed on the impedance matching segment, and then the metal layer and other dielectric layers are alternately arranged from bottom to top, with the top layer being the metal layer.

[0013] The above technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

[0014] The transmission line structure provided in the embodiment of the present application has stripline segments at both ends for electrical connection to the connection points of the circuit board; in the high-frequency transmission section, two groups of conductive columns, the first conductive layer and the second conductive layer enclose a receiving cavity, and the electromagnetic wave is confined in the dielectric substrate in the receiving cavity, and the field is transmitted in a waveguide manner; the impedance matching section is used to achieve impedance matching between the high-frequency transmission section and the stripline segment. Since the high-frequency transmission section takes into account the advantages of both waveguide and microstrip structures, while being able to meet the high-frequency signal transmission, its transmission loss is lower, and compared with the traditional flexible circuit board transmission line, the thickness of the high-frequency transmission section is thinner, so it is also convenient for the transmission line structure to be routed inside the terminal device, and the space occupied is smaller.

[0015] In some embodiments, the first conductive layer and the second conductive layer are both planar structure layers.

[0016] It can be understood that the planar structure layer refers to a layer structure with a planar outer surface and a high degree of flatness. That is, the side of the first conductive layer away from the dielectric substrate should be planar, and the side of the second conductive layer away from the dielectric substrate should be planar. In this way, the high-frequency transmission section can better adapt to the corresponding installation requirements. For example, the high-frequency transmission section can be set between the battery and the shell of the terminal device, and the gap between the battery and the shell is used for routing. Compared with the traditional flexible circuit board transmission line, the spacing between the first conductive layer and the second conductive layer of the high-frequency transmission section is smaller, that is, the overall thickness of the high-frequency transmission section is smaller, providing a larger accommodation space for the battery.

[0017] In some embodiments, at least one first thinning groove is formed on the first conductive layer, and the width of the first thinning groove is the same as the width of the first conductive layer; or,

[0018] At least one second thinning groove is formed on the second conductive layer, and the width of the second thinning groove is the same as the width of the second conductive layer; or,

[0019] At least one first thinning groove is formed on the first conductive layer, and the width of the first thinning groove is the same as the width of the first conductive layer. At least one second thinning groove is formed on the second conductive layer, and the width of the second thinning groove is the same as the width of the second conductive layer.

[0020] It can be understood that, according to actual use requirements, one or more thinning grooves can be formed on the first conductive layer and / or the second conductive layer. Here, the thinning groove is a groove structure formed by inward depression of the conductive layer, and the groove width of the thinning groove is the same as the width of the corresponding conductive layer, that is, the thinning groove penetrates the conductive layer in the width direction. Therefore, in actual assembly scenarios, the thinning groove can be used for routing.

[0021] In some embodiments, the first thinning groove corresponds to the second thinning groove, or the length of the first thinning groove is equal to the length of the second thinning groove.

[0022] It can be understood that in the actual assembly scenario, the first thinning groove and the second thinning groove are made to correspond to each other, that is, routing can be set at both the upper and lower ends of the high-frequency transmission section to pass through the corresponding thinning groove. In addition, the length of the thinning groove refers to the groove length of the thinning groove in the length direction of the conductive layer. When the lengths of the two thinning grooves are equal, routings of the same width can pass through.

[0023] In some embodiments, the distance between the first conductive layer and the second conductive layer is h, the distance from the bottom surface of the first thinning groove to the surface of the second conductive layer is p, and 2 / 3h<p<h.

[0024] It can be understood that the distance between the first conductive layer and the second conductive layer is h, which means that the thickness of the dielectric substrate between the first conductive layer and the second conductive layer is h; the distance from the bottom surface of the first thinning groove to the surface of the second conductive layer is p, which means that the thickness of the dielectric substrate between the first thinning groove and the second conductive layer is p. The propagation characteristics of the high-frequency transmission section are similar to those of the rectangular waveguide, with only a slight difference in the propagation constant. Therefore, it can be considered that when the width of the high-frequency transmission section is constant, its equivalent impedance should be proportional to the thickness of the dielectric substrate. As for the matching requirements of the transmission line structure, the standing wave ratio should be as close to 1 as possible, then the reflection system is basically 0, and in practice, the standing wave ratio needs to be less than 1.5, otherwise the link risk caused by impedance adaptation is relatively large. Therefore, within the range of 2 / 3h<p<h, the link risk caused by impedance difference can be reduced.

[0025] In some embodiments, the distance between the first conductive layer and the second conductive layer is h, the distance from the bottom surface of the second thinning groove to the surface of the first conductive layer is q, and 2 / 3h<q<h.

[0026] It can be understood that the distance between the first conductive layer and the second conductive layer is h, which means that the thickness of the dielectric substrate between the first conductive layer and the second conductive layer is h; the distance from the bottom surface of the second thinning groove to the surface of the first conductive layer is q, which means that the thickness of the dielectric substrate between the second thinning groove and the first conductive layer is q. Similarly, within the range of 2 / 3h<q<h, the link risk caused by impedance difference can be reduced.

[0027] In some embodiments, at least one third thinning groove is formed on the bottom surface of the first thinning groove, the groove width of the third thinning groove is the same as the width of the first conductive layer, and the groove length of the third thinning groove is less than the groove length of the first thinning groove; or,

[0028] At least one fourth thinning groove is formed on the bottom surface of the second thinning groove, the groove width of the fourth thinning groove is the same as the width of the second conductive layer, and the groove length of the fourth thinning groove is less than the groove length of the second thinning groove; or,

[0029] At least one third thinning groove is formed on the bottom surface of the first thinning groove, the groove width of the third thinning groove is the same as the width of the first conductive layer, and the groove length of the third thinning groove is smaller than the groove length of the first thinning groove; and at least one fourth thinning groove is formed on the bottom surface of the second thinning groove, the groove width of the fourth thinning groove is the same as the width of the second conductive layer, and the groove length of the fourth thinning groove is smaller than the groove length of the second thinning groove.

[0030] It can be understood that, according to actual use requirements, secondary thinning can be performed in the thinning area of ​​the high-frequency transmission section, and the goal of the secondary thinning can be to increase the thinning range so as to accommodate a target object with a thicker thickness.

[0031] In some embodiments, the distance between the first conductive layer and the second conductive layer is h, the distance from the bottom surface of the first thinning groove to the surface of the second conductive layer is p, the distance from the bottom surface of the third thinning groove to the surface of the second conductive layer is m, and p= .

[0032] It can be understood that the distance between the first conductive layer and the second conductive layer is h, which means that the thickness of the dielectric substrate between the first conductive layer and the second conductive layer is h; the distance from the bottom of the first thinning groove to the surface of the second conductive layer is p, which means that the thickness of the dielectric substrate between the first thinning groove and the second conductive layer is p; the distance from the bottom of the third thinning groove to the surface of the second conductive layer is m, which means that the thickness of the dielectric substrate between the third thinning groove and the second conductive layer is m. Since the proportion of secondary thinning is large, an impedance matching section should be added between the secondary thinning area and the non-thinning area. Then, the equivalent impedance of the impedance matching section is equal to the square root of the product of the equivalent impedance of the non-thinning area and the equivalent impedance of the secondary thinning area. Therefore, when the width of the high-frequency transmission section is constant, the thickness of the dielectric substrate corresponding to each area should have the above relationship, that is, p= .

[0033] In some embodiments, the distance between the first conductive layer and the second conductive layer is h, the distance from the bottom surface of the second thinning groove to the surface of the first conductive layer is q, and the distance from the bottom surface of the fourth thinning groove to the surface of the first conductive layer is n, q= .

[0034] It can be understood that the distance between the first conductive layer and the second conductive layer is h, which means that the thickness of the dielectric substrate between the first conductive layer and the second conductive layer is h; the distance from the bottom surface of the second thinning groove to the surface of the first conductive layer is q, which means that the thickness of the dielectric substrate between the second thinning groove and the first conductive layer is q; the distance from the bottom surface of the fourth thinning groove to the surface of the first conductive layer is n, which means that the thickness of the dielectric substrate between the fourth thinning groove and the first conductive layer is n. Similarly, when the width of the high-frequency transmission section is constant, the thickness of the dielectric substrate corresponding to each area should have the above relationship, that is, q=

[0035] In some embodiments, the spacing between corresponding conductive columns in two groups is w, the spacing between two adjacent conductive columns in the same group is s, and the inner diameter of each conductive column is d;

[0036] Among them, d / w<0.2, s / d<2.

[0037] It can be understood that after the operating frequency is determined, the operating wavelength can be confirmed. If the high-frequency transmission section is equivalent to a rectangular waveguide, then there is a certain relationship between w and the operating wavelength. At the same time, in order to reduce the risk of electromagnetic leakage, d and w should satisfy d / w<0.2, and s and d should satisfy s / d<2.

[0038] In a second aspect, the present application provides a method for preparing a transmission line structure, comprising the following steps:

[0039] Incoming materials are pressed and etched, two first incoming materials are pressed together, and the metal layer on the first end surface of the pressed first incoming materials is etched to expose the dielectric layer, so as to form a high-frequency transmission section area;

[0040] Spraying a seed metal layer on the dielectric layer exposed in the high-frequency transmission section to form a seed metal layer;

[0041] Drilling, drilling in the high-frequency transmission section area to form a plurality of first through holes, and each of the first through holes passes through the seed metal layer;

[0042] Electroplating: electroplating the entire first end surface to form a metal plating layer on the first end surface and in each first through hole;

[0043] Secondary pressing, pressing the second incoming material onto the first end surface, so that the pressed second incoming material has a second end surface away from the first end surface;

[0044] The cover is removed, and the metal layer corresponding to the second end surface and the high-frequency transmission area is etched, so that the second material forms two convex parts protruding from the first end surface, and the medium covering the high-frequency transmission section area is removed to expose the high-frequency transmission section area;

[0045] Secondary drilling: drilling holes in the two convex parts to form second through holes, and the second through holes penetrate the convex parts and the first incoming material;

[0046] Secondary electroplating to form a metal plating layer in the second through hole;

[0047] Surface circuit etching: the metal layer corresponding to the high-frequency transmission section area is etched to form the corresponding circuit.

[0048] The above technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

[0049] The transmission line structure prepared by the method for preparing the transmission line structure provided in the embodiment of the present application can meet the requirements of high-frequency signal transmission while having smaller insertion loss and a thinner overall thickness.

[0050] In some embodiments, between the step of the incoming material press etching and the step of spraying the seed metal layer, the following steps are further included:

[0051] The dielectric layer is thinned, and the dielectric layer in the high-frequency transmission section is locally thinned.

[0052] It is understandable that when the local area of ​​the high-frequency transmission segment needs to be thinned once or multiple times, the dielectric layer needs to be thinned first, for example, by CNC machining to determine the length and depth of the thinned area, and then a seed metal layer is formed in the subsequent spraying process.

[0053] In a third aspect, the present application provides a terminal device, comprising a shell, a main control circuit board, a sub-circuit board, a battery and the above-mentioned transmission line structure, the main control circuit board, the sub-circuit board, the battery and the transmission line structure are all arranged in the shell, one end of the transmission line structure is connected to the main control circuit board, and the other end is connected to the sub-circuit board, and the transmission line structure is located between the outer wall of the battery and the inner wall of the shell.

[0054] The above technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

[0055] The terminal device provided in the embodiment of the present application, based on the above-mentioned transmission line structure, has a shell that can accommodate batteries with higher energy density and has lower insertion loss while meeting high-frequency signal transmission requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A cross-sectional view of a terminal device provided in Embodiment 1 of the present application;

[0057] Figure 2 A bottom view of the terminal device provided in Embodiment 1 of the present application;

[0058] Figure 3 A cross-sectional view of a terminal device provided in Embodiment 2 of the present application;

[0059] Figure 4 A bottom view of a terminal device provided in Embodiment 2 of the present application;

[0060] Figure 5 A cross-sectional view of a terminal device provided in Embodiment 3 of the present application;

[0061] Figure 6 A bottom view of a terminal device provided in Embodiment 3 of the present application;

[0062] Figure 7 A schematic diagram of the structure of the transmission line provided in Example 1 of the present application;

[0063] Figure 8 A cross-sectional view of the transmission line structure provided in Example 1 of the present application;

[0064] Fig. 9A schematic diagram of the structure of the transmission line provided in the second embodiment of the present application;

[0065] Fig.10 A cross-sectional view of the transmission line structure provided in Embodiment 2 of the present application;

[0066] Fig.11 A schematic diagram of the structure of the transmission line provided in the third embodiment of the present application;

[0067] Fig.12 A cross-sectional view of the transmission line structure provided in Embodiment 3 of the present application;

[0068] Fig.13 A cross-sectional view of a transmission line structure provided in Embodiment 4 of the present application;

[0069] Fig.14 A cross-sectional view of a transmission line structure provided in Embodiment 5 of the present application;

[0070] Fig.15 A partial diagram of a transmission structure provided in an embodiment of the present application;

[0071] Fig.16 A flow chart of a method for preparing a transmission line structure provided in an embodiment of the present application;

[0072] Fig.17 A schematic diagram of insertion loss of a stripline segment of a transmission line structure provided in an embodiment of the present application at different frequencies;

[0073] Fig.18 A schematic diagram of the insertion loss of the high-frequency transmission segment of the transmission line structure provided in an embodiment of the present application at different frequencies.

[0074] Among them, the reference numerals in the figure are:

[0075] 1000. terminal equipment;

[0076] 100, transmission line structure; 200, housing; 201, bottom shell; 202, middle frame; 203, cover glass; 300, main control circuit board; 400, auxiliary circuit board; 500, battery;

[0077] 10. high-frequency transmission section; 11. dielectric substrate; 12. first conductive layer; 13. second conductive layer; 14. conductive column; 15. first thinning groove; 16. second thinning groove; 17. third thinning groove; 18. fourth thinning groove;

[0078] 20. Impedance matching section;

[0079] 30. Strip segment. DETAILED DESCRIPTION

[0080] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0081] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0082] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "top", "bottom", "inside", "outside", "upper", "lower", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0083] The terms "first", "second", "third", "fourth", "fifth", "sixth", etc. are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, the first deformation space and the second deformation space are only used to distinguish different deformation spaces, and their order is not limited. The first deformation space can also be named as the second deformation space, and the second deformation space can also be named as the first deformation space without departing from the scope of the various described embodiments. In addition, the terms "first", "second", etc. do not limit the indicated features to be necessarily different.

[0084] In this application, unless otherwise clearly specified and limited, the terms "connected", "connection" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0085] In this application, "and / or" is only a description of the association relationship of associated objects, indicating that there can be three relationships; for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0086] It should be noted that, in this application, words such as "in some embodiments", "exemplarily", "for example", etc. are used to indicate examples, illustrations or descriptions. Any embodiment or design described in this application as "in some embodiments", "exemplarily", "for example" should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "in some embodiments", "exemplarily", "for example", etc. is intended to present related concepts in a specific way.

[0087] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0088] The number and types of antennas in terminal devices are increasing. Usually, these antennas are set around the middle frame of the terminal device. It is necessary to transmit radio frequency signals between the antenna modules on the main circuit board and the auxiliary circuit board, and between the antenna modules on the main circuit board and the frame.

[0089] Current transmission carriers and methods include: using wired signal lines in the frame area, but the outer diameter of the wired signal line itself and the corresponding avoidance space required result in a large space being occupied, which is not conducive to increasing the battery capacity of the terminal device; or using FPC (Flexible Printed Circuit) to connect between the battery compartment and the back cover of the terminal device, or between the battery compartment and the frame.

[0090] Among them, FPC is used for signal transmission between the main circuit board and the antenna module. The transmission signal is generally below 15GHz. In order to reduce the loss of the intermediate frequency signal in the FPC segment, the general method is to increase the stacking thickness of the FPC. At the same time, due to the dielectric loss, the insertion loss also increases significantly when transmitting higher frequency signals. Therefore, there is a problem that the thickness of the current FPC cannot be reduced and it is difficult to transmit higher frequency signals.

[0091] In view of this, the present application provides a transmission line structure, including a high-frequency transmission section, stripline segments arranged at opposite ends of the high-frequency transmission section, and impedance matching end sections for achieving impedance matching. Among them, the stripline segment is used to electrically connect to the connection point of the circuit board or the connection point of the antenna module. The high-frequency transmission section is used for signal transmission, and the transmission line that takes into account the advantages of waveguide and microstrip structures can realize high-performance high-frequency signal planar circuits. At the same time, it can transmit higher frequency signals, with less insertion loss and thinner thickness. In this way, it replaces the traditional FPC transmission line and has the characteristics of occupying less space in the terminal equipment, meeting the high-frequency signal transmission requirements, and low loss.

[0092] The terminal device 1000 involved in the embodiments of the present application may include a handheld device, a vehicle-mounted device, a wearable device, a computing device, or other processing devices connected to a wireless modem. It may also include a cellular phone, a smart phone, a personal digital assistant (PDA) computer, a tablet computer, a laptop computer, a machine type communication (MTC) terminal, a point of sales (POS), a vehicle-mounted computer, and other terminal devices 1000 with imaging functions.

[0093] The embodiment of the present application does not impose any special restrictions on the specific form of the terminal device 1000. For the convenience of description and understanding, the following description is made by taking the terminal device 1000 as a mobile phone as an example.

[0094] Please refer to Figures 1 to 6 , Figure 1 , Figure 3 , Figure 5 The terminal device 1000 provided for the embodiment of the present application is a cross-sectional view of a mobile phone, which includes a housing 200 , a main control circuit board 300 , a sub-circuit board 400 , a battery 500 and a transmission line structure 100 .

[0095] Among them, the shell 200 should include a bottom shell 201, a middle frame 202 arranged on the bottom shell 201, and a cover glass 203 covering the middle frame 202. The battery 500 is arranged on the bottom shell 201. The main control circuit board 300 and the auxiliary circuit board 400 are respectively located at opposite ends of the battery 500. The main control circuit board 300 and the auxiliary circuit board 400 are both provided with a connection position for connecting to the transmission line structure 100, and the connection position is a board to board (BTB) connector.

[0096] Meanwhile, the main control circuit board 300 and the auxiliary circuit board 400 are respectively located on opposite sides of the battery 500 , and the connection positions of the main control circuit board 300 and the auxiliary circuit board 400 are respectively electrically connected to opposite ends of the transmission line structure 100 .

[0097] Since the transmission line structure 100 can meet the requirements of high-frequency signal transmission while having lower transmission loss, and compared with the traditional flexible circuit board transmission line, the thickness of the high-frequency transmission section 10 of the transmission line structure 100 is thinner, it is also convenient for the transmission line structure 100 to be routed inside the terminal device and occupies less space. In this way, the thickness of the battery 500 can be thicker, providing space for a battery 500 with a higher energy density.

[0098] For example, Figure 1 and Figure 2 As shown, the high-frequency transmission section 10 of the transmission line structure 100 is in a straight state, and the high-frequency transmission section 10 of the transmission structure is located between the inner wall of the bottom shell 201 of the shell 200 and the outer wall of the battery 500. Compared with the traditional flexible circuit board transmission line, the high-frequency transmission section 10 of the transmission line structure 100 is thinner and can be used to increase the capacity of the battery 500.

[0099] For example, Figure 3 and Figure 4 As shown, local thinning is performed on the high-frequency transmission section 10 of the transmission line structure 100. The thinned area is used for various FPCs with a certain thickness and corresponding avoidance structures to pass through, such as FPC transmission lines. Further thinning the thickness of the high-frequency transmission section 10 of the transmission line structure 100 can be used to increase the capacity of the battery 500.

[0100] For example, Figure 5 and Figure 6 As shown, the high-frequency transmission section 10 of the transmission line structure 100 is thinned for a second time, and a gradient is formed with the unthinned area, and the structural gradient matches the corresponding impedance. The second thinned area is used for various FPCs and avoidance structures with a certain thickness to pass through, such as a charging FPC. The thickness of the high-frequency transmission section 10 of the transmission line structure 100 is further thinned, which can be used to increase the capacity of the battery 500.

[0101] Please refer to Figures 7 to 12 A transmission line structure 100 provided in an embodiment of the present application includes a high-frequency transmission segment 10, an impedance matching segment 20 and a stripline segment 30.

[0102] Among them, the high-frequency transmission section 10 is a transmission line that combines the advantages of waveguide and microstrip structures, and can realize high-performance high-frequency signal planar circuits. At the same time, it can transmit higher frequency signals with smaller insertion loss and thinner thickness.

[0103] Specifically, the high-frequency transmission section 10 includes a dielectric substrate 11, a first conductive layer 12 and a second conductive layer 13 respectively arranged on opposite sides of the dielectric substrate 11, and a plurality of conductive columns 14. Here, the dielectric substrate 11 can be ceramics (barium aluminum titanate, lithium niobate, etc.), polytetrafluoroethylene, silicon, aluminum nitride, magnesium fluoride, etc. Among them, ceramics such as barium aluminum titanate and lithium niobate have the advantages of high dielectric constant and low loss; polytetrafluoroethylene has the advantages of low dielectric constant and low loss, and is widely used in high-frequency signal transmission; silicon is used in integrated circuits, especially in high-frequency and millimeter-wave bands; aluminum nitride can provide good electrical performance and thermal management; fluoride has low loss and high frequency stability.

[0104] The opposite sides of the dielectric substrate 11 refer to the top surface and the bottom surface of the dielectric substrate 11. It can be understood that the first conductive layer 12 is provided on the top surface of the dielectric substrate 11, and the second conductive layer 13 is provided on the bottom surface of the dielectric substrate 11. Each conductive layer can be a metal layer, such as a copper layer, a silver layer, etc.; or a non-metal layer, such as a graphite layer, etc.

[0105] Each conductive column 14 is disposed through the first conductive layer 12, the dielectric substrate 11, and the second conductive layer 13, and one end of the conductive column 14 is electrically connected to the first conductive layer 12, and the other end of the conductive column 14 is electrically connected to the second conductive layer 13. The conductive column 14 refers to a metal structural member with a hollow structure. In the actual manufacturing process, holes can be drilled on the first conductive layer 12, the dielectric substrate 11, and the second conductive layer 13, and a conductive layer is formed in the hole by electroplating, spraying, etc. For example, the conductive layer is a metal layer, so that one end of the metal layer is connected to the first conductive layer 12, and the other end of the metal layer is connected to the second conductive layer 13.

[0106] Furthermore, each conductive column 14 is divided into two groups and is respectively located on the opposite edge sides of the first conductive layer 12. Each conductive column 14 in the same group is arranged at intervals along the signal transmission direction and corresponds to each conductive column 14 in the other group. Here, the two groups of conductive columns 14, the first conductive layer 12 and the second conductive layer 13 enclose a receiving cavity, so that the electromagnetic wave is confined between the first conductive layer 12, the second conductive layer 13 and each conductive column 14, and the field is transmitted in the dielectric substrate 11 in a waveguide manner.

[0107] It should be noted that each group of conductive columns 14 should be distributed on the long edge side of the first conductive layer 12, which is the edge side of the first conductive layer 12 in the length direction, and the long edge side is also the edge side extending along the signal transmission direction. The conductive columns 14 in the same group should be arranged at intervals along the length direction of the first conductive layer 12, and the spacing between the conductive columns 14 can be equal spacing or variable spacing, and the spacing between two adjacent conductive columns 14 should be the distance between the central axes of the two conductive columns 14.

[0108] Here, the plane where the first conductive layer 12 is located and the plane where the second conductive layer 13 is located can be arranged in parallel. Then, when each conductive column 14 is penetrated perpendicular to the first conductive layer 12, each conductive column 14 is also perpendicular to the second conductive layer 13. At this time, it is also feasible to use the second conductive layer 13 as a reference system. For example, each conductive column 14 is divided into two groups and is respectively located on opposite edge sides of the second conductive layer 13.

[0109] Of course, in other embodiments, the penetration direction of the conductive column 14 may be non-perpendicular to the plane where the first conductive layer 12 is located.

[0110] The impedance matching section 20 is disposed at two opposite ends of the first conductive layer 12 along the signal transmission direction.

[0111] It can be understood that the two opposite ends of the first conductive layer 12 along the signal transmission direction refer to the two opposite ends in the length direction of the first conductive layer 12. The impedance matching section 20 is used to achieve impedance matching between the stripline section 30 and the high-frequency transmission section 10, and also has a feeding function. At the same time, the impedance matching section 20 should be at the same level as the first conductive layer 12. In this way, the impedance matching section 20 is also placed on the dielectric substrate 11.

[0112] For example, Fig.15 As shown, the impedance matching section 20 is a strip structure, which includes two parts, one part is a trapezoidal structure connected to the middle position of the end of the first conductive layer 12, and the other part is a rectangular structure connected to the trapezoidal structure.

[0113] For example, the impedance matching section 20 is a strip structure having a uniform width, one end of which is connected to the middle of the end of the first conductive layer, and a notch corresponding to the strip structure is formed on the end of the first conductive layer.

[0114] The stripline segments 30 are disposed at two opposite ends of the first conductive layer 12 along the signal transmission direction and are placed on the dielectric substrate 11 . The stripline segments 30 are connected to the first conductive layer 12 via corresponding impedance matching segments 20 .

[0115] It can be understood that there is a feeding connection point between the stripline segment 30 and the impedance matching segment 20 , for example, a conductive member can be connected to the stripline segment 30 and the impedance matching segment 20 .

[0116] The stripline segment 30 is used to electrically connect to the connection point of the circuit board. The stripline segment 30 can be composed of at least one dielectric layer and a metal layer, wherein the bottom dielectric layer is placed on the impedance matching segment 20, and then metal layers and other dielectric layers are alternately arranged from bottom to top, with the topmost layer being the metal layer.

[0117] For example, Fig.17 and Fig.18 As shown, at the same width, for example, 3.5 mm, the insertion loss of the stripline segment 30 and the high-frequency transmission segment 10 in different frequency bands are compared.

[0118] Among them, the total thickness of the stripline segment 30 is 268 microns, and when the frequency band signals are 15 GHz, 30 GHz, and 35 GHZ, the corresponding insertion losses are -0.038 dB / mm, -0.065 dB / mm, and -0.073 dB / mm, respectively; and the total thickness of the high-frequency transmission segment 10 is 169 microns, and when the frequency band signals are 15 GHz, 30 GHz, and 35 GHZ, the corresponding insertion losses are 0 dB / mm, -0.054 dB / mm, and -0.035 dB / mm, respectively.

[0119] In summary, it can be seen that the insertion loss of the high-frequency transmission section 10 is related to the thickness of the dielectric substrate 11 . As the thickness of the dielectric substrate 11 increases, the transmission power increases, and the insertion loss decreases.

[0120] The transmission line structure 100 provided in the embodiment of the present application has stripline segments 30 at both ends for electrical connection to the connection points of the circuit board; in the high-frequency transmission segment 10, two groups of conductive columns 14, the first conductive layer 12 and the second conductive layer 13 enclose a receiving cavity, and the electromagnetic wave is confined in the dielectric substrate 11 in the receiving cavity, and the field is transmitted in a waveguide manner; the impedance matching segment 20 is used to achieve impedance matching between the high-frequency transmission segment 10 and the stripline segment 30. Since the high-frequency transmission segment 10 takes into account the advantages of both waveguide and microstrip structures, while being able to meet the high-frequency signal transmission, its transmission loss is lower, and, compared with the traditional flexible circuit board transmission line, the high-frequency transmission segment 10 is thinner, so it is also convenient for the transmission line structure 100 to be routed inside the terminal device, and the space occupied is smaller.

[0121] Please refer to Figure 7 and Figure 8 In some embodiments, the first conductive layer 12 and the second conductive layer 13 are both planar structure layers.

[0122] It can be understood that the planar structure layer refers to a layer structure with a planar outer surface and a high degree of flatness. That is, the side of the first conductive layer 12 away from the dielectric substrate 11 should be planar, and the side of the second conductive layer 13 away from the dielectric substrate 11 should be planar. In this way, the high-frequency transmission section 10 can better adapt to the corresponding installation requirements. For example, the high-frequency transmission section 10 can be set between the battery 500 and the shell of the terminal device, and the gap between the battery 500 and the shell is used for routing. Compared with the traditional flexible circuit board transmission line, the spacing between the first conductive layer 12 and the second conductive layer 13 of the high-frequency transmission section 10 is smaller, that is, the overall thickness of the high-frequency transmission section 10 is smaller, providing a larger accommodating space for the battery 500.

[0123] Please refer to Fig. 9 , Fig.10 and Fig.13 In some embodiments, at least one first thinning groove 15 is formed on the first conductive layer 12, and the width of the first thinning groove 15 is the same as the width of the first conductive layer 12; or

[0124] At least one second thinning groove 16 is formed on the second conductive layer 13, and the width of the second thinning groove 16 is the same as the width of the second conductive layer 13; or,

[0125] At least one first thinning groove 15 is formed on the first conductive layer 12 , and the width of the first thinning groove 15 is the same as the width of the first conductive layer 12 . At least one second thinning groove 16 is formed on the second conductive layer 13 , and the width of the second thinning groove 16 is the same as the width of the second conductive layer 13 .

[0126] It can be understood that, according to actual use requirements, one or more thinning grooves can be formed on the first conductive layer 12 and / or the second conductive layer 13. Here, the thinning groove is a groove structure formed by inward depression of the conductive layer, and the groove width of the thinning groove is the same as the width of the corresponding conductive layer, that is, the thinning groove penetrates the conductive layer in the width direction. Therefore, in actual assembly scenarios, the thinning groove can be used for routing.

[0127] For example, Fig. 9 and Fig.10 As shown, the transmission line structure 100 is applied to a mobile phone to connect the main control circuit board 300 and the auxiliary circuit board 400, and the high-frequency transmission section 10 is located between the battery 500 and the shell 200. At this time, a first thinning groove 15 is formed in the middle of the first conductive layer 12. The width of the first thinning groove 15 is the same as the width of the first conductive layer 12, and the opening of the first thinning groove 15 is facing the battery 500. Therefore, the first thinning groove 15 can be used for FPC routing or accommodating avoidance structure, etc.

[0128] In other embodiments, a second thinning groove 16 may also be formed on the second conductive layer 13 . In this case, the opening of the second thinning groove 16 faces the housing 200 .

[0129] In other embodiments, a first thinning groove 15 may be formed on the first conductive layer 12, and a second thinning groove 16 may be formed on the second conductive layer 13. The two thinning grooves may be overlapped or staggered in accordance with actual usage scenarios.

[0130] In some embodiments, the first thinning groove 15 corresponds to the second thinning groove 16 , or the length of the first thinning groove 15 is equal to the length of the second thinning groove 16 .

[0131] It can be understood that in an actual assembly scenario, the first thinning groove 15 and the second thinning groove 16 are made to correspond to each other, that is, wiring can be set at both the upper and lower ends of the high-frequency transmission section to pass through the corresponding thinning grooves. In addition, the length of the thinning groove refers to the length of the groove of the thinning groove in the length direction of the conductive layer. When the lengths of the two thinning grooves are equal, wiring of the same width can pass through.

[0132] Please refer to Fig.10 In some embodiments, the distance between the first conductive layer 12 and the second conductive layer 13 is h, the distance from the bottom surface of the first thinning groove 15 to the surface of the second conductive layer 13 is p, and 2 / 3h<p<h.

[0133] It can be understood that the distance between the first conductive layer 12 and the second conductive layer 13 is h, which means that the thickness of the dielectric substrate 11 between the first conductive layer 12 and the second conductive layer 13 is h; the distance from the bottom surface of the first thinning groove 15 to the surface of the second conductive layer 13 is p, which means that the thickness of the dielectric substrate 11 between the first thinning groove 15 and the second conductive layer 13 is p. The propagation characteristics of the high-frequency transmission section 10 are similar to those of the rectangular waveguide, with only a slight difference in the propagation constant. Therefore, it can be considered that when the width of the high-frequency transmission section 10 is constant, its equivalent impedance should be proportional to the thickness of the dielectric substrate 11. As for the matching requirements of the transmission line structure 100, the standing wave ratio should be as close to 1 as possible, then the reflection system is basically 0, and in practice, the standing wave ratio needs to be less than 1.5, otherwise the link risk caused by impedance adaptation is relatively large. Therefore, within the range of 2 / 3h<p<h, the link risk caused by impedance difference can be reduced.

[0134] Please refer to Fig.13 In some embodiments, the distance between the first conductive layer 12 and the second conductive layer 13 is h, the distance from the bottom surface of the second thinning groove 16 to the surface of the first conductive layer 12 is q, and 2 / 3h<q<h.

[0135] It can be understood that the distance between the first conductive layer 12 and the second conductive layer 13 is h, which means that the thickness of the dielectric substrate 11 between the first conductive layer 12 and the second conductive layer 13 is h; the distance from the bottom surface of the second thinning groove 16 to the surface of the first conductive layer 12 is q, which means that the thickness of the dielectric substrate 11 between the second thinning groove 16 and the first conductive layer 12 is q. Similarly, within the range of 2 / 3h<q<h, the link risk caused by the impedance difference can be reduced.

[0136] Please refer to Fig.11 , Fig.12 and Fig.14 In some embodiments, at least one third thinning groove 17 is formed on the bottom surface of the first thinning groove 15, the groove width of the third thinning groove 17 is the same as the width of the first conductive layer 12, and the groove length of the third thinning groove 17 is less than the groove length of the first thinning groove 15; or,

[0137] At least one fourth thinning groove 18 is formed on the bottom surface of the second thinning groove 16, the groove width of the fourth thinning groove 18 is the same as the width of the second conductive layer 13, and the groove length of the fourth thinning groove 18 is less than the groove length of the second thinning groove 16; or,

[0138] At least one third thinning groove 17 is formed on the bottom surface of the first thinning groove 15, the groove width of the third thinning groove 17 is the same as the width of the first conductive layer 12, and the groove length of the third thinning groove 17 is smaller than the groove length of the first thinning groove 15; and at least one fourth thinning groove 18 is formed on the bottom surface of the second thinning groove 16, the groove width of the fourth thinning groove 18 is the same as the width of the second conductive layer 13, and the groove length of the fourth thinning groove 18 is smaller than the groove length of the second thinning groove 16.

[0139] It can be understood that, according to actual use requirements, secondary thinning can be performed in the thinned area of ​​the high-frequency transmission section 10, and the goal of the secondary thinning can be to increase the thinning range so as to accommodate a target object with a thicker thickness.

[0140] For example, Fig.11 and Fig.12As shown, the transmission line structure 100 is applied to a mobile phone to connect the main control circuit board 300 and the auxiliary circuit board 400, and the high-frequency transmission section 10 is located between the battery 500 and the shell 200. At this time, a first thinning groove 15 is formed in the middle of the first conductive layer 12, and the width of the first thinning groove 15 is the same as the width of the first conductive layer 12. At the same time, a third thinning groove 17 is formed on the groove bottom surface of the first thinning groove 15, and the groove width of the third thinning groove 17 is the same as the width of the first conductive layer 12, and the groove length of the third thinning groove 17 is less than the groove length of the first thinning groove 15, and the opening of the first thinning groove 15 and the opening of the third thinning groove 17 are both facing the battery 500. Therefore, through the secondary thinning method, a thicker FPC can be routed or a avoidance structure can be accommodated.

[0141] In other embodiments, a second thinning groove 16 may also be formed on the second conductive layer 13, and, further, a fourth thinning groove 18 may be formed on the bottom surface of the second thinning groove 16, the groove width of the fourth thinning groove 18 is the same as the width of the second conductive layer 13, and the groove length of the fourth thinning groove 18 is less than the groove length of the second thinning groove 16. At this time, the opening of the second thinning groove 16 and the opening of the fourth thinning groove 18 are facing the shell 200.

[0142] In other embodiments, a first thinning groove 15 may be formed on the first conductive layer 12, and a third thinning groove 17 may be formed on the bottom surface of the first thinning groove 15. At the same time, a second thinning groove 16 may be formed on the second conductive layer 13, and a fourth thinning groove 18 may be formed on the bottom surface of the second thinning groove 16. The two secondary thinning grooves may be arranged to overlap or staggered in accordance with actual usage scenarios.

[0143] Please refer to Fig.12 In some embodiments, the distance between the first conductive layer 12 and the second conductive layer 13 is h, the distance from the bottom surface of the first thinning groove 15 to the surface of the second conductive layer 13 is p, and the distance from the bottom surface of the third thinning groove 17 to the surface of the second conductive layer 13 is m, p= .

[0144] It can be understood that the distance between the first conductive layer 12 and the second conductive layer 13 is h, which means that the thickness of the dielectric substrate 11 between the first conductive layer 12 and the second conductive layer 13 is h; the distance from the bottom surface of the first thinning groove 15 to the surface of the second conductive layer 13 is p, which means that the thickness of the dielectric substrate 11 between the first thinning groove 15 and the second conductive layer 13 is p; the distance from the bottom surface of the third thinning groove 17 to the surface of the second conductive layer 13 is m, which means that the thickness of the dielectric substrate 11 between the third thinning groove 17 and the second conductive layer 13 is m. Since the proportion of secondary thinning is large, an impedance matching section 20 should be added between the secondary thinning area and the non-thinning area. Then, the equivalent impedance of the impedance matching section 20 is equal to the square root of the product of the equivalent impedance of the non-thinning area and the equivalent impedance of the secondary thinning area. Therefore, when the width of the high-frequency transmission section is constant, the thickness of the dielectric substrate 11 corresponding to each area should have the above relationship, that is, p= .

[0145] Please refer to Fig.14 In some embodiments, the distance between the first conductive layer 12 and the second conductive layer 13 is h, the distance from the bottom surface of the second thinning groove 16 to the surface of the first conductive layer 12 is q, and the distance from the bottom surface of the fourth thinning groove 18 to the surface of the first conductive layer 12 is n, q= .

[0146] It can be understood that the distance between the first conductive layer 12 and the second conductive layer 13 is h, which means that the thickness of the dielectric substrate 11 between the first conductive layer 12 and the second conductive layer 13 is h; the distance from the bottom surface of the second thinning groove 16 to the surface of the first conductive layer 12 is q, which means that the thickness of the dielectric substrate 11 between the second thinning groove 16 and the first conductive layer 12 is q; the distance from the bottom surface of the fourth thinning groove 18 to the surface of the first conductive layer 12 is n, which means that the thickness of the dielectric substrate 11 between the fourth thinning groove 18 and the first conductive layer 12 is n. Similarly, when the width of the high-frequency transmission section is constant, the thickness of the dielectric substrate 11 corresponding to each region should have the above relationship, that is, q= .

[0147] Please refer to Fig.15 In some embodiments, the spacing between corresponding conductive columns 14 in two groups is w, the spacing between two adjacent conductive columns 14 in the same group is s, and the inner diameter of each conductive column 14 is d;

[0148] Among them, d / w<0.2, s / d<2.

[0149] It can be understood that after the operating frequency is determined, the operating wavelength can be confirmed. If the high-frequency transmission section is equivalent to a rectangular waveguide, then there is a certain relationship between w and the operating wavelength. At the same time, in order to reduce the risk of electromagnetic leakage, d and w should satisfy d / w<0.2, and s and d should satisfy s / d<2.

[0150] For example, d=0.075 mm, s=1.5d=0.1125 mm.

[0151] There is a corresponding relationship between the operating frequency and the dielectric substrate 11, for example, λ=c / ,in, is the operating frequency, is a constant of the dielectric substrate 11, and λ is the working wavelength. That is, when the working frequency and the constant of the dielectric substrate 11 are determined, the working wavelength can be determined. In addition, the high-frequency transmission section is equivalent to a rectangular waveguide, and the equivalent width of the rectangular waveguide also has a corresponding relationship with w, d, and s. w eff =w-1.08d 2 / s+0.1d 2 / w, where w eff is the equivalent width of the rectangular waveguide. At a certain operating frequency, w eff <λ<2w eff .

[0152] Please refer to Fig.16 The present application provides a method for manufacturing a transmission line structure 100, comprising the following steps:

[0153] S001, pressing and etching the incoming materials, pressing two first incoming materials together, etching the metal layer on the first end surface of the pressed first incoming materials to expose the dielectric layer, so as to form a high-frequency transmission section area.

[0154] Here, the first end surface refers to the end surface after the two first incoming materials are pressed together. The first end surface is etched to remove the metal layer on the first end surface, and the area where the dielectric layer is exposed is the high-frequency transmission section area.

[0155] S002, spraying a seed metal layer, spraying on the dielectric layer exposed in the high-frequency transmission section area to form a seed metal layer.

[0156] S003, drilling: drilling in the high-frequency transmission section area to form a plurality of first through holes, and each of the first through holes passes through the seed metal layer.

[0157] Here, each first through hole penetrates the seed metal layer, the dielectric layer and another metal layer of the first material. Meanwhile, parameters such as the spacing between each first through hole can be determined according to the frequency and wavelength of the transmission signal.

[0158] S004, electroplating: electroplating the entire first end surface to form a metal plating layer on the first end surface and in each first through hole.

[0159] It can be understood that, in terms of spatial structure, the metal plating layer formed in the first through hole can also be connected to the seed metal layer on the first end surface, and can also be connected to another metal layer of the first incoming material.

[0160] S005, secondary pressing, pressing the second incoming material onto the first end face, so that the pressed second incoming material has a second end face away from the first end face.

[0161] Here, the purpose of the secondary lamination is to form the stripline segment 30 in the non-high frequency transmission segment area of ​​the first end surface.

[0162] S006, uncovering, etching the metal layer corresponding to the second end surface and the high-frequency transmission area, forming two convex parts protruding from the first end surface with the second material, and removing the medium covering the high-frequency transmission section area to expose the high-frequency transmission section area.

[0163] Here, the two protrusions are formed on the first end surface of two strip line segments 30, and the strip line segment 30 is composed of a metal layer and a dielectric layer. Of course, in other embodiments, multiple metal layers and multiple dielectric layers can be provided, that is, the number of second incoming materials in the secondary lamination is increased.

[0164] S007, secondary drilling, drilling holes in the two protrusions to form second through holes, and the second through holes penetrate the protrusions and the first incoming material.

[0165] Here, the second through hole is used to penetrate the stripline segment 30 and the feeding portion of the non-high frequency transmission segment area on the first end face, that is, the impedance matching segment 20 .

[0166] S008. Secondary electroplating to form a metal plating layer in the second through hole.

[0167] Here, the metal plating layer formed in the second through hole is used to connect the stripline segment 30 and the feeding portion (impedance matching segment 20) in the non-high frequency transmission segment area on the first end face, thereby realizing signal transmission.

[0168] S009, surface circuit etching: etching the metal layer corresponding to the high-frequency transmission section area to form a corresponding circuit.

[0169] The transmission line structure 100 manufactured by the manufacturing method of the transmission line structure 100 provided in the embodiment of the present application can meet the requirements of high-frequency signal transmission while having a smaller insertion loss and a thinner overall thickness.

[0170] In some embodiments, between the steps of etching the incoming material and spraying the seed metal layer, the following steps are further included:

[0171] S00101. Thinning the dielectric layer: locally thinning the dielectric layer in the high-frequency transmission section.

[0172] It is understandable that when a local area of ​​the high-frequency transmission segment 10 needs to be thinned once or multiple times, the dielectric layer needs to be thinned first, for example, by CNC machining to determine the length and depth of the thinned area, and then a seed metal layer is formed in the subsequent spraying process.

[0173] For example, a primary thinning may be performed on one side of the dielectric substrate 11 , or a secondary thinning may be performed on a region where a primary thinning has been completed.

[0174] Please refer to Figure 1 and Figure 2 The present application provides a terminal device, including a shell 200, a main control circuit board 300, a sub-circuit board 400, a battery 500 and the above-mentioned transmission line structure 100, the main control circuit board 300, the sub-circuit board 400, the battery 500 and the transmission line structure 100 are all arranged in the shell 200, one end of the transmission line structure 100 is connected to the main control circuit board 300, and the other end is connected to the sub-circuit board 400, and the transmission line structure 100 is located between the outer wall of the battery 500 and the inner wall of the shell 200.

[0175] The terminal device provided in the embodiment of the present application has the above-mentioned transmission line structure 100, and the shell 200 of the terminal device can accommodate a battery 500 with higher energy density, and has lower insertion loss while meeting high-frequency signal transmission requirements.

[0176] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A transmission line structure, characterized in that: include: A high-frequency transmission section, the high-frequency transmission section comprises a dielectric substrate, a first conductive layer and a second conductive layer respectively arranged on opposite sides of the dielectric substrate, and a plurality of conductive tubes, each of the conductive tubes is penetrated through the first conductive layer, the dielectric substrate and the second conductive layer, one end of the conductive tube is electrically connected to the first conductive layer, the other end of the conductive tube is electrically connected to the second conductive layer, and each of the conductive tubes is divided into two groups and respectively located on opposite edge sides of the first conductive layer, each of the conductive tubes in the same group is arranged at intervals along the signal transmission direction, and corresponds to each of the conductive tubes in the other group one by one, at least one first thinning groove is formed on the first conductive layer, and the width of the first thinning groove is the same as the width of the first conductive layer; An impedance matching section, wherein the impedance matching section is provided at two opposite ends of the first conductive layer along the signal transmission direction; A stripline segment, wherein the stripline segment is arranged at two opposite ends of the first conductive layer along the signal transmission direction and is placed on the dielectric substrate, wherein the stripline segment is connected to the first conductive layer through the corresponding impedance matching segment, and the stripline end is composed of at least one dielectric layer and a metal layer assembly, wherein the dielectric layer at the bottom layer is placed on the blocking matching segment, and then the metal layer and other dielectric layers are alternately arranged from bottom to top, and the top layer is the metal layer.

2. The transmission line structure according to claim 1, characterized in that: The first conductive layer and the second conductive layer are both planar structure layers.

3. The transmission line structure according to claim 1, characterized in that: At least one second thinning groove is formed on the second conductive layer, and the width of the second thinning groove is the same as the width of the second conductive layer.

4. The transmission line structure according to claim 1, characterized in that: At least one first thinning groove is formed on the first conductive layer, and the width of the first thinning groove is the same as the width of the first conductive layer; and at least one second thinning groove is formed on the second conductive layer, and the width of the second thinning groove is the same as the width of the second conductive layer.

5. The transmission line structure according to claim 4, characterized in that: The first thinning groove corresponds to the second thinning groove, or the length of the first thinning groove is equal to the length of the second thinning groove.

6. The transmission line structure according to claim 2, characterized in that: The distance between the first conductive layer and the second conductive layer is h, the distance from the bottom surface of the first thinning groove to the surface of the second conductive layer is p, and 2 / 3h<p<h.

7. The transmission line structure according to claim 3, characterized in that: The distance between the first conductive layer and the second conductive layer is h, the distance from the bottom surface of the second thinning groove to the surface of the first conductive layer is q, and 2 / 3h<q<h.

8. The transmission line structure according to claim 2, characterized in that: At least one third thinning groove is formed on the bottom surface of the first thinning groove, the groove width of the third thinning groove is the same as the width of the first conductive layer, and the groove length of the third thinning groove is less than the groove length of the first thinning groove.

9. The transmission line structure according to claim 3, characterized in that: At least one fourth thinning groove is formed on the bottom surface of the second thinning groove, the groove width of the fourth thinning groove is the same as the width of the second conductive layer, and the groove length of the fourth thinning groove is less than the groove length of the second thinning groove.

10. The transmission line structure according to claim 8, characterized in that: The distance between the first conductive layer and the second conductive layer is h, the distance from the bottom surface of the first thinning groove to the surface of the second conductive layer is p, the distance from the bottom surface of the third thinning groove to the surface of the second conductive layer is m, and p= .

11. The transmission line structure according to claim 9, characterized in that: The distance between the first conductive layer and the second conductive layer is h, the distance from the bottom surface of the second thinning groove to the surface of the first conductive layer is q, and the distance from the bottom surface of the fourth thinning groove to the surface of the first conductive layer is n, q= .

12. The transmission line structure according to any one of claims 1 to 11, characterized in that: The spacing between the corresponding conductive tube pillars in two groups is w, the spacing between two adjacent conductive tube pillars in the same group is s, and the inner diameter of each conductive tube pillar is d; Among them, d / w<0.2, s / d<2.

13. A method for preparing a transmission line structure according to any one of claims 1 to 12, characterized in that: include: Incoming materials are pressed and etched, two first incoming materials are pressed together, and the metal layer on the first end surface of the pressed first incoming materials is etched to expose the dielectric layer, so as to form a high-frequency transmission section area; Thinning the dielectric layer: locally thinning the dielectric layer in the high-frequency transmission section; Spraying a seed metal layer on the dielectric layer exposed in the high-frequency transmission section to form a seed metal layer; Drilling, drilling in the high-frequency transmission section area to form a plurality of first through holes, and each of the first through holes passes through the seed metal layer; Electroplating: electroplating the entire first end surface to form a metal plating layer on the first end surface and in each first through hole; Secondary pressing, pressing the second incoming material onto the first end surface, so that the pressed second incoming material has a second end surface away from the first end surface; The cover is removed, and the metal layer corresponding to the second end surface and the high-frequency transmission area is etched, so that the second material forms two convex parts protruding from the first end surface, and the medium covering the high-frequency transmission section area is removed to expose the high-frequency transmission section area; Secondary drilling: drilling holes in the two convex parts to form second through holes, and the second through holes penetrate the convex parts and the first incoming material; Secondary electroplating to form a metal plating layer in the second through hole; Surface circuit etching: the metal layer corresponding to the high-frequency transmission section area is etched to form the corresponding circuit.

14. A terminal device, characterized in that: It comprises a shell, a main control circuit board, a sub-circuit board, a battery and a transmission line structure as claimed in any one of claims 1 to 12, wherein the main control circuit board, the sub-circuit board, the battery and the transmission line structure are all arranged in the shell, one end of the transmission line structure is connected to the main control circuit board, and the other end is connected to the sub-circuit board, and the transmission line structure is located between the outer wall of the battery and the inner wall of the shell.

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