Integrated suspended wire circuit based on injection molding process and applications thereof

Abstract

The application discloses an integrated suspended line circuit based on an injection molding process and application thereof. The integrated suspended line circuit is formed by sequentially stacking an upper cover plate, a middle circuit layer and a lower cover plate which are integrally formed by a preset injection mold; a recess is formed on the inner side surface of the upper cover plate and / or the lower cover plate, so that at least one cavity is formed in the self-encapsulated structure; the surface of the plastic substrate of the injection molded upper cover plate, middle circuit layer and lower cover plate and the inner wall of the cavity structure are covered with a metal conductive layer, so that a suspended transmission structure is formed above and / or below the integrated suspended signal line of the middle circuit layer, the integrated suspended line signal line is connected with a preset electronic element, and circuit interconnection is realized. The integrated suspended line circuit scheme based on the injection molding technology uses the characteristics of high-efficiency molding and batch production of the injection molding process, and provides a new idea for low-cost and lightweight manufacturing of the integrated suspended line platform in the microwave and millimeter wave frequency band.

Description

Technical Field

[0001] This invention relates to the field of integrated suspension circuit technology, and in particular to an integrated suspension line circuit based on injection molding process and its application. Background Technology

[0002] Integrated suspension lines, as a new type of radio frequency transmission line structure, have the advantages of low loss, self-encapsulation, and easy integration, and show broad application prospects in millimeter wave and even terahertz frequency bands.

[0003] Traditional integrated suspended line circuits are typically implemented using multi-layer PCB stacking, metal cavity processing, or silicon-based etching processes, but they have the following shortcomings or defects:

[0004] 1. Traditional machining (such as CNC milling) is costly and heavy, making it difficult to meet the high-volume, lightweight requirements of consumer electronics and automotive radar. 2. Although silicon-based MEMS technology has high precision, the equipment is expensive and the process is complex, resulting in high costs. 3. Although dielectric integrated suspension lines (SISL) are implemented using standard multilayer PCB technology, the bonding process between the multilayer dielectric substrate and the metal layer is cumbersome, requiring precise alignment and high-temperature, high-pressure lamination. This results in many steps, a long cycle time, and the stacking of multilayer dielectric substrates increases the overall thickness and weight.

[0005] Therefore, improving the aforementioned deficiencies or defects in the fabrication of integrated suspension line circuits is of significant technical importance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings and defects of the prior art and to provide an integrated suspension line circuit based on injection molding process and its application.

[0007] This invention is achieved through the following technical solution:

[0008] According to another aspect of the present invention, an integrated suspended line circuit based on injection molding is provided, comprising a self-encapsulating structure formed by sequentially stacking an upper cover plate, an intermediate circuit layer, and a lower cover plate, each integrally formed by a preset injection mold; grooves are formed on the inner surfaces of the upper cover plate and / or the lower cover plate, thereby forming at least one cavity inside the self-encapsulating structure; the surfaces of the plastic substrates of the injection-molded upper cover plate, intermediate circuit layer, and lower cover plate, as well as the inner walls of the cavity structure, are covered with a metal conductive layer, thereby forming a suspended transmission structure above and / or below the integrated suspended signal line of the intermediate circuit layer; the integrated suspended signal line is connected to preset electronic components to realize circuit interconnection.

[0009] Preferably, the integrated suspended signal line is supported and installed by an injection-molded support structure with a preset hollow shape in the intermediate circuit layer.

[0010] Preferably, the upper cover plate, the middle core circuit layer and the lower cover plate are positioned and sealed together by a positioning mechanism; preferably, the positioning mechanism includes a positioning post and / or a positioning hole.

[0011] Preferably, the conductive metal layer is formed by an electroplating process.

[0012] Preferably, the upper cover plate, the intermediate circuit layer, the lower cover plate, and the cavity have regular or irregular three-dimensional structural shapes; preferably, the upper cover plate includes a cover plate with a hollow structure on its surface, for the antenna radiating unit on the intermediate circuit layer to radiate electromagnetic energy outward and / or receive external electromagnetic energy.

[0013] Preferably, the plastic substrate is injection molded using at least one of the following materials: liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyetherimide (PEI), and modified polyimide (MPI).

[0014] Preferably, the surface of the plastic substrate is subjected to surface roughening treatment and catalyst activation treatment in sequence to form a preset bonding interface. A metal plating layer is formed at the preset bonding interface by chemical plating, and then the metal conductive layer is formed by electroplating. Preferably, the surface of the metal conductive layer is not subjected to chromium passivation treatment to prevent oxidation of the metal conductive layer.

[0015] Preferably, the metal plating layer is a nickel plating layer, and the metal conductive layer is a copper plating layer.

[0016] Preferably, the preset electronic components include one or more of active devices and circuits, passive devices and circuits, antennas, chips, resistors, inductors, and capacitors.

[0017] According to another aspect of the invention, the integrated suspension line circuit based on the injection molding process is provided for use in filters, power dividers, couplers, antennas, power amplifiers, or low-noise amplifier modules.

[0018] This invention utilizes injection molding technology to achieve low-cost, lightweight manufacturing of radio frequency circuits. The air cavity and support structure are directly formed through injection molds, and the conductive layer of the integrated suspension circuit is formed by combining surface metallization processes (such as copper electroplating). Thus, while ensuring good radio frequency / microwave transmission performance, it significantly reduces processing costs, simplifies the process flow, and increases the freedom of structural design.

[0019] This invention can directly and integrally mold the air cavity and signal line groove through injection molding, eliminating the need for the complex pressing process of multi-layer substrates. By adopting injection molding technology, it provides new possibilities for low-cost and lightweight manufacturing of integrated suspension line circuits. Furthermore, the integrated suspension line circuit structure based on injection molding technology simplifies the process, reduces costs, and lightens weight.

[0020] Its packaging structure is suitable for high-performance, low-cost, and lightweight integrated suspension line circuits in vehicle radar, 5G / 6G communication modules, and aerospace electronic systems. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the injection-molded integrated suspension line circuit according to an embodiment of the present invention.

[0022] Figure 2 This is a flowchart of the metallization process on the surface of a plastic substrate according to an embodiment of the present invention.

[0023] Figure 3 This is a cross-sectional view of an injection-molded integrated suspension line circuit with added chips, components, or active / passive components and circuit interconnections, according to an embodiment of the present invention.

[0024] Figure 4 This is a typical structural diagram of the injection-molded integrated suspension line circuit according to an embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram of an injection-molded integrated suspension line circuit with an added antenna interconnect structure, according to an embodiment of the present invention.

[0026] Figures 6-8 This is a schematic diagram of injection-molded integrated suspension line circuits with different three-dimensional structures according to embodiments of the present invention. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0028] See Figures 1 to 8 As shown, according to an embodiment of the present invention, the integrated suspended line circuit based on injection molding process comprises a self-encapsulating structure formed by sequentially stacking an upper cover plate, an intermediate circuit layer, and a lower cover plate, each integrally formed by a preset injection mold; grooves are formed on the inner surfaces of the upper cover plate and / or the lower cover plate, thereby forming at least one cavity inside the self-encapsulating structure; the surfaces of the plastic substrates of the injection-molded upper cover plate, intermediate circuit layer, and lower cover plate, as well as the inner walls of the cavity structure, are covered with a metal conductive layer, thereby forming a suspended transmission structure above and / or below the integrated suspended signal line of the intermediate circuit layer; the integrated suspended signal line is connected to preset electronic components to realize circuit interconnection.

[0029] The integrated suspension line circuit scheme proposed in this invention based on injection molding technology utilizes the efficient molding and mass production characteristics of injection molding to provide a new approach for low-cost and lightweight manufacturing of integrated suspension line platforms in the microwave and millimeter-wave frequency bands.

[0030] The integrated suspended line circuit based on injection molding of the present invention has an upper cover plate, a lower cover plate, and an intermediate circuit layer structure made of injection molded plastic substrate. The inner surface of the upper cover plate and / or the lower cover plate, that is, the surface corresponding to the intermediate circuit layer, is formed with at least one groove structure by injection molding, thereby forming at least one cavity inside the overall structure after self-encapsulation. In this way, suspended transmission cavities are formed above and below the integrated suspended signal line of the core main circuit arranged on the intermediate circuit layer.

[0031] According to an embodiment of the present invention, the integrated suspended signal line may be soldered or surface-mounted with active devices, passive devices, antennas, chips, resistors, inductors, capacitors, and other common electronic components to achieve surface interconnection.

[0032] According to embodiments of the present invention, the integrated suspended line circuit based on injection molding has a support structure for the integrated suspended signal lines that is injection molded into a pre-defined hollow structure according to the circuit structure. This structure is integrally injection molded with the plastic substrate, and includes, but is not limited to, continuous ridges, multiple separate pillars, and support strips arranged along the signal line direction. According to embodiments of the present invention, the height and spacing of the support structure are precisely controlled by the cavity dimensions of the injection mold, eliminating the need for subsequent machining.

[0033] According to an embodiment of the present invention, the upper cover plate, the intermediate core circuit layer and the lower cover plate are positioned and sealed together by a positioning mechanism; as an example, the positioning mechanism includes a positioning post and / or a positioning hole.

[0034] According to an embodiment of the present invention, the integrated suspension line circuit based on injection molding process of the present invention has two ends of the plastic substrate of the intermediate circuit layer that can be integrally injection molded with the corresponding transition structure. The transition structure connects to standard waveguides, coplanar waveguides (GCPWs), coaxial cables, or vertical interconnect surface mounts to facilitate the testing of circuit modules and system-level interconnection.

[0035] like Figure 2 As shown in the embodiments of this application, a conductive metal layer, such as a copper layer, is formed on the surface of the plastic substrate after metallization treatment. According to the embodiments of this application, the surface of the plastic substrate is metallized using the following typical steps: injection molding, plastic surface roughening, catalyst activation treatment, electroless nickel plating, electroplating of a conductive metal layer, and passivation treatment. Through the above steps, a uniform, dense, and well-adhesive conductive metal layer can be formed on the surface of the plastic substrate and the inner wall of the cavity, meeting the requirements of integrated suspended line circuits for low-loss transmission and electromagnetic shielding.

[0036] It should be noted that, in some implementations, a selective gold plating step can be added after electroplating the conductive metal layer to improve high-frequency performance and solderability.

[0037] According to embodiments of this application, the plastic substrate is injection molded using at least one of liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyetherimide (PEI), and modified polyimide (MPI).

[0038] According to an embodiment of this application, based on the definition of the circuit pattern of the intermediate circuit layer, a selective chemical plating method is used to protect the non-circuit area with a mask and deposit a metal layer, such as a copper layer or an aluminum layer, only in the predetermined circuit pattern area. The suspended signal line of the core circuit is formed by the metal deposition process.

[0039] According to embodiments of this application, for core circuits requiring high graphic precision, the intermediate circuit layer can also be directly made of metal plates, such as copper or aluminum plates, instead of the copper-plated structure on the injection-molded substrate surface. The upper and lower cover plates are still formed using injection molding, and the required high-precision signal line patterns are formed by laser etching of the metal plates, thereby obtaining higher graphic precision and better conductivity.

[0040] like Figure 3 , Figure 4 As shown, this illustration depicts a typical structure of an integrated suspended line circuit based on injection molding, according to an embodiment of this application. It comprises an upper cover plate 11, a lower cover plate 12, and an intermediate circuit layer 13 stacked together to form a closed, self-encapsulating structure with a cavity, achieving electromagnetic shielding and signal grounding. The inner surfaces of the upper cover plate 11 and the lower cover plate 12 have grooves, resulting in a closed, non-perforated structure. A support structure 14 is injection-molded onto the intermediate circuit layer 13 to support the integrated suspended signal line suspended within the cavity. The shape of the intermediate circuit layer 13 can be customized and integrally injection-molded as needed. Chips, components, active / passive devices, and interconnections can be arbitrarily added according to design requirements to achieve more complex circuit layouts and higher integration.

[0041] like Figure 5 The diagram shows a cross-sectional and perspective view of an injection-molded integrated suspension wire structure with added antenna interconnect according to an embodiment of this application. It is constructed by stacking a perforated upper cover plate 21, an intermediate circuit layer 22, and a lower cover plate 23. An antenna is disposed on the intermediate circuit layer 22. Through the perforation of the upper cover plate 21, the antenna of the intermediate circuit layer 22, as a radiating element, radiates electromagnetic energy and / or receives external electromagnetic energy. The perforated upper cover plate 21 above the intermediate circuit layer 22 can be fitted with metamaterial structures, grid structures, etc., according to design requirements to achieve one or more of the following functions: beamforming, gain enhancement, sidelobe suppression, bandwidth expansion, polarization adjustment, or directional electromagnetic wave radiation.

[0042] According to an embodiment of this application, the hollowed-out upper cover plate 21, like the upper cover plate 11, adopts an injection-molded integrated structure and its surface is covered with a conductive metal layer.

[0043] According to embodiments of this application, the injection-molded integrated suspension wire circuit can be designed as a three-dimensional, regular, or irregular structure according to actual application requirements, and its cavity cross-section can also be flexibly selected as rectangular, trapezoidal, circular, or other irregular shapes. For example... Figure 6 , Figure 7 and Figure 8 As shown, it illustrates an injection-molded integrated suspension line circuit of different three-dimensional shapes according to an embodiment of this application. As an example, Figure 6 The overall structure is a rectangular three-dimensional structure composed of an upper cover plate 31, a middle circuit layer 32, and a lower cover plate 33 stacked together. The internal hollow or supporting structure of the middle circuit layer has an irregular or regular shape. Figure 7 The integrated suspension circuit structure is a roughly circular three-dimensional structure composed of an upper cover plate 41, an intermediate circuit layer 42, and a lower cover plate 43 stacked together. The internal hollow or support mechanism of the intermediate circuit layer is of a regular shape. Figure 8 The whole structure is a triangular or triangular three-dimensional structure composed of an upper cover plate 51, an intermediate circuit layer 52, and a lower cover plate 53. The hollow or supporting mechanism of the internal intermediate circuit layer structure is a regular or irregular three-dimensional shape.

[0044] According to the embodiments of this application, the injection-molded integrated suspension line circuit achieves a high degree of structural freedom due to the use of injection molding. This ensures that the plastic substrate has sufficient mechanical strength to support the circuit and the package, while also achieving low-loss transmission performance of the injection-molded integrated suspension line circuit.

[0045] Compared to traditional PCB or silicon-based processes, the injection-molded integrated suspension line circuit scheme of the embodiments of this application has greatly improved design flexibility and can meet the design requirements of various microwave and millimeter-wave circuits such as filters, power dividers, couplers, and antennas.

[0046] The injection-molded integrated suspension circuit of this invention is suitable for the packaging structure of high-performance, low-cost, and lightweight integrated suspension line circuits in vehicle radar, 5G / 6G communication modules, and aerospace electronic systems.

[0047] The present invention is not limited to the details of the above exemplary embodiments. It is obvious to those skilled in the art that the shape, cavity structure, support form, metallization method, etc. of the plastic substrate can be modified and combined in various ways according to actual needs.

[0048] The integrated suspension line circuit based on injection molding according to embodiments of the present invention can be applied in filters, power dividers, couplers, antennas, power amplifiers, or low-noise amplifier modules.

[0049] The injection-molded integrated suspension circuit of this invention utilizes injection molding technology to achieve low-cost and lightweight manufacturing of radio frequency circuits. The air cavity and support structure are directly formed through injection molds, and the conductive layer of the integrated suspension circuit is formed by combining surface metallization processes (such as copper electroplating). Thus, while ensuring good radio frequency / microwave transmission performance, it significantly reduces processing costs, simplifies the process flow, and increases the freedom of structural design.

[0050] The injection-molded integrated suspension circuit of this invention can directly form the air cavity and signal line groove in one piece through the injection mold, without the need for the complex pressing process of multi-layer substrates. By adopting the injection molding process, it provides a new possibility for low-cost and lightweight manufacturing of integrated suspension circuits. Moreover, the integrated suspension circuit structure based on the injection molding process simplifies the process, reduces costs and lightens weight.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0052] Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the invention.

[0053] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An integrated suspension line circuit based on injection molding process, characterized in that, A self-encapsulating structure is formed by sequentially stacking an upper cover plate, an intermediate circuit layer, and a lower cover plate, each integrally molded by a pre-set injection mold. Grooves are formed on the inner surfaces of the upper cover plate and / or the lower cover plate, thereby creating at least one cavity inside the self-encapsulating structure. A metal conductive layer covers the surfaces of the plastic substrates of the injection-molded upper cover plate, intermediate circuit layer, and lower cover plate, as well as the inner walls of the cavity structure, thus forming a suspended transmission structure above and / or below the integrated suspended signal line of the intermediate circuit layer. The integrated suspended signal line is connected to pre-set electronic components to achieve circuit interconnection.

2. The integrated suspension line circuit based on injection molding process according to claim 1, characterized in that, The integrated suspended signal line is supported and installed by an injection-molded support structure with a preset hollow shape in the intermediate circuit layer.

3. The integrated suspension line circuit based on injection molding process according to claim 1, characterized in that, The upper cover plate, the middle core circuit layer and the lower cover plate are positioned and sealed together by a positioning mechanism; preferably, the positioning mechanism includes a positioning post and / or a positioning hole.

4. The integrated suspension line circuit based on injection molding process according to claim 1, characterized in that, The conductive metal layer is formed by an electroplating process.

5. The integrated suspension line circuit based on injection molding process according to claim 1, characterized in that, The upper cover plate, the middle circuit layer, the lower cover plate, and the cavity have regular or irregular three-dimensional structural shapes. Preferably, the upper cover plate includes a cover plate with a hollow structure on its surface, for the antenna radiating unit on the intermediate circuit layer to radiate electromagnetic energy outward and / or receive external electromagnetic energy.

6. The integrated suspension line circuit based on injection molding process according to claim 1, characterized in that, The plastic substrate is injection molded using at least one of the following materials: liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyether imide (PEI), and modified polyimide (MPI).

7. The integrated suspension line circuit based on injection molding process according to claim 1, characterized in that, The surface of the plastic substrate is subjected to surface roughening treatment and catalyst activation treatment in sequence to form a preset bonding interface. A metal plating layer is formed at the preset bonding interface by chemical plating, and then the metal conductive layer is formed by electroplating. Preferably, the surface of the metal conductive layer is not subjected to chromium passivation treatment to prevent oxidation of the metal conductive layer.

8. The integrated suspension line circuit based on injection molding process according to claim 7, characterized in that, The metal plating layer is a nickel plating layer, and the metal conductive layer is a copper plating layer.

9. The integrated suspension line circuit based on injection molding process according to claim 1, characterized in that, The preset electronic components include one or more of active devices and circuits, passive devices and circuits, antennas, chips, resistors, inductors, and capacitors.

10. The integrated suspension line circuit based on injection molding process according to any one of claims 1-9 is used in filters, power dividers, couplers, antennas, power amplifiers or low noise amplifier modules.

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