A microwave radio module and method of assembling the same

Abstract

The application discloses a microwave radio frequency module and an assembling method thereof, which comprises: a partition plate, which divides a module assembly cavity into a high-frequency cavity and a low-frequency cavity; a high-frequency soft substrate and a low-frequency PCB plate, the high-frequency soft substrate is arranged in the high-frequency cavity, and the low-frequency PCB plate is arranged in the low-frequency cavity; and a stepped metal pin, which comprises a stepped portion located on the low-frequency cavity side and a connecting portion located in the high-frequency cavity; wherein the low-frequency PCB plate is provided with a via hole matched with the stepped metal pin, the partition plate and the high-frequency soft substrate are provided with through holes matched with the stepped metal pin, the stepped portion is fixedly connected with the low-frequency PCB plate, and the connecting portion is connected with the high-frequency soft substrate through a gold wire or a gold belt; wherein the diameter of the connecting portion is 0.3mm-0.6mm, and the height of the connecting portion is 2.0mm-2.3mm. The microwave radio frequency module and the assembling method thereof can greatly improve the anti-vibration impact performance of the microwave radio frequency module assembly and simultaneously improve the connection reliability of the high-frequency soft substrate and the low-frequency PCB plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave radio frequency module assembly packaging, and in particular to a microwave radio frequency module and an assembly method thereof. BACKGROUND

[0002] Microwave radio frequency module assemblies are widely used in high-frequency electronic systems such as radars, satellites, and electronic countermeasure fields. The module assemblies usually adopt a partition plate to form two independent high-frequency cavities and low-frequency cavities. A high-frequency soft substrate is arranged in the high-frequency cavity for realizing high-frequency signal processing and transmission. A low-frequency PCB is arranged in the low-frequency cavity for realizing control, power supply, and low-frequency signal processing functions. The signal interconnection between the two is usually connected by high-temperature wires, customized connectors, or insulators.

[0003] However, the connection methods in the prior art have many limitations. The connection by high-temperature wires is usually achieved by welding or crimping. The connection points of the high-temperature wires are prone to stress concentration in a vibration environment, which may cause solder fatigue or fracture, affecting the long-term reliability of the electrical connection. The conductive contact of the customized connector depends on the mechanical contact pressure between the pins and the sockets. When the module works in a vibration or impact environment, a small displacement will occur between the contacts, causing the contact pressure to fluctuate, resulting in changes in contact resistance and unstable signals, further reducing the conduction reliability. The insulator is fixed at both ends by soldering to the high-frequency soft substrate and the low-frequency PCB, which is a rigid connection. In a high-low temperature alternating or mechanical vibration impact environment, the stress is difficult to release effectively, affecting the connection reliability.

[0004] Therefore, there is an urgent need for an improved microwave radio frequency module and an assembly method thereof to solve the reliability problems in the prior art. SUMMARY

[0005] The present application aims to at least solve one of the technical problems in the prior art. To this end, one object of the present application is to propose a microwave radio frequency module. The module has a small volume and can greatly improve the vibration and impact resistance of the microwave radio frequency module assembly.

[0006] Another object of the present application is to propose an assembly method of a microwave radio frequency module, which can significantly improve the connection reliability of the high-frequency soft substrate and the low-frequency PCB.

[0007] According to the present application, a microwave radio frequency module is proposed, comprising:

[0008] a partition plate, which divides the module assembly cavity into independent high-frequency and low-frequency cavities;

[0009] A high-frequency flexible substrate and a low-frequency PCB board, wherein the high-frequency flexible substrate is disposed in the high-frequency cavity and the low-frequency PCB board is disposed in the low-frequency cavity;

[0010] A stepped metal pin, the stepped metal pin including a stepped portion located on the low-frequency cavity side and a connecting portion located in the high-frequency cavity;

[0011] The low-frequency PCB board is provided with a through hole that mates with the stepped metal pin, and the cavity plate and the high-frequency flexible substrate are provided with a through hole that mates with the stepped metal pin. The stepped metal pin passes through the through hole and the through hole in sequence. The stepped part is fixedly connected to the low-frequency PCB board, and the connecting part is connected to the high-frequency flexible substrate by gold wire or gold strip.

[0012] The diameter of the connecting part is 0.3mm to 0.6mm, the height of the connecting part is 2.0mm to 2.3mm, and the diameter of the through hole of the partition plate is larger than the diameter of the connecting part.

[0013] In some examples of the present invention, the number of stepped metal pins corresponds to the number of chip bonding pins on the high-frequency flexible substrate.

[0014] In some examples of the present invention, the distribution positions of the stepped metal pins correspond to the distribution positions of the lead pads of the high-frequency flexible substrate.

[0015] In some examples of the present invention, the electrical connection between the connecting portion and the lead pad of the high-frequency flexible substrate is made of gold wire, and the diameter of the gold wire is 25 μm.

[0016] In some examples of the present invention, the electrical connection between the connecting portion and the lead pad of the high-frequency flexible substrate is a first gold strip or a second gold strip, wherein the first gold strip has a width of 150 μm and a thickness of 12.5 μm, and the second gold strip has a width of 300 μm and a thickness of 25 μm.

[0017] The assembly method of the microwave radio frequency module proposed according to the present invention includes:

[0018] A high-frequency flexible substrate is fixedly installed in the high-frequency cavity of the module component cavity, and a low-frequency PCB board is fixedly installed in the low-frequency cavity of the module component cavity.

[0019] The stepped metal pins are passed sequentially through the low-frequency PCB board and the cavity plate and extended into the high-frequency cavity, so that the stepped part is fixedly connected to the low-frequency PCB board and the connection part is located in the high-frequency cavity.

[0020] The connecting part is connected with the lead bonding pad of the high-frequency soft substrate through a gold wire or a gold tape, so as to form a transition soft connection between the low-frequency PCB board and the high-frequency soft substrate.

[0021] The diameter of the connecting part is 0.3mm-0.6mm, the height of the connecting part is 2.0mm-2.3mm, and the diameter of the through hole of the partition plate is greater than the diameter of the connecting part.

[0022] In some examples of the present application, the fixed connection between the stepped part and the low-frequency PCB board is welding.

[0023] In some examples of the present application, the connecting part and the lead bonding pad of the high-frequency soft substrate are connected through a gold wire, and the diameter of the gold wire is 25μm.

[0024] In some examples of the present application, the connecting part and the lead bonding pad of the high-frequency soft substrate are connected through a first gold tape or a second gold tape, wherein the width of the first gold tape is 150μm, and the thickness is 12.5μm, the width of the second gold tape is 300μm, and the thickness is 25μm.

[0025] In some examples of the present application, a pressing block is applied in the high-frequency cavity to keep the fit during the fixing of the high-frequency soft substrate, and is cured at 120℃ for about 2 hours.

[0026] Additional aspects and advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood to have the following beneficial effects by the practice of the present application:

[0027] In the microwave radio frequency module provided by the embodiment of the present application, the vertical interconnection of the low-frequency PCB board and the high-frequency soft substrate is realized through the stepped metal pin, and the soft connection structure formed by the gold wire or the gold tape improves the connection reliability of the microwave radio frequency module. Specifically, the stepped metal pin realizes the shortest path transmission of the high-frequency signal between the low-frequency PCB board and the high-frequency soft substrate, effectively guarantees the stable work of the radio frequency characteristics under the Ku band (such as 17.5GHz); at the same time, the soft connection structure can actively absorb and release stress under the conditions of high-low temperature cycle and mechanical vibration, thereby avoiding the problems of broken pins or falling off of the bonding pad caused by the traditional hard connection mode. The two cooperate to ensure the complete transmission of the high-frequency signal while enhancing the reliability of the connection, thereby significantly improving the long-term reliability of the microwave radio frequency module in complex environment. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without any creative work based on the embodiments of the present application shall fall within the protection scope of the present application.

[0029] Figure 1 A connection schematic diagram of a high-frequency soft substrate and a low-frequency PCB board according to an embodiment of the present application;

[0030] Figure 2 A front view of a stepped metal pin according to an embodiment of the present application;

[0031] Figure 3 A structure schematic diagram of a low-frequency PCB board according to an embodiment of the present application;

[0032] Figure 4 A structure schematic diagram of a high-frequency soft substrate according to an embodiment of the present application;

[0033] Figure 5 A Figure 4 A local enlarged schematic diagram at A in FIG. 4;

[0034] Figure 6 A schematic diagram for calculating the impedance of the stepped metal pin in AppCAD software;

[0035] Figure 7 A radio frequency transmission characteristic diagram of the stepped metal pin.

[0036] Explanation of reference signs:

[0037] 100 - partition plate;

[0038] 200 - high-frequency soft substrate; 210 - lead pad;

[0039] 300 - low-frequency PCB board;

[0040] 400 - stepped metal pin; 410 - stepped portion; 420 - connecting portion. DETAILED DESCRIPTION

[0041] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without any creative work based on the embodiments of the present application shall fall within the protection scope of the present application.

[0042] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the features defined with "first", "second" can be explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified and limited, the term "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0043] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the features defined with "first", "second" can be explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified and limited, the term "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] The embodiments of the present application are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0045] Figure 1 The connection schematic diagram of the high-frequency soft substrate and the low-frequency PCB board provided according to the embodiment of the present application is shown in the figure; Figure 2 The front view of the stepped metal pin provided according to the embodiment of the present application is shown in the figure; Figure 3 The structure schematic diagram of the low-frequency PCB board provided according to the embodiment of the present application is shown in the figure; Figure 4 The structure schematic diagram of the high-frequency soft substrate provided according to the embodiment of the present application is shown in the figure; Figure 5 The Figure 4 The local enlarged schematic diagram at A in the figure; Figure 6 The schematic diagram of calculating the impedance of the stepped metal pin in the AppCAD software is shown in the figure; Figure 7 The radio frequency transmission characteristic diagram of the stepped metal pin is shown in the figure.

[0046] The following will be described with reference to Figures 1-5The application discloses a microwave radio frequency module, which comprises a cavity plate 100, the cavity plate 100 separates a module assembly cavity into a high-frequency cavity and a low-frequency cavity; a high-frequency soft substrate 200 and a low-frequency PCB 300, the high-frequency soft substrate 200 is arranged in the high-frequency cavity, and the low-frequency PCB 300 is arranged in the low-frequency cavity; a stepped metal pin 400, the stepped metal pin 400 comprises a stepped portion 410 arranged on the low-frequency cavity side and a connecting portion 420 arranged in the high-frequency cavity; wherein the low-frequency PCB 300 is provided with a via hole matched with the stepped metal pin 400, the cavity plate 100 and the high-frequency soft substrate 200 are provided with through holes matched with the stepped metal pin 400, the stepped metal pin 400 sequentially passes through the via hole and the through hole, the stepped portion 410 is fixedly connected with the low-frequency PCB 300, and the connecting portion 420 is connected with the high-frequency soft substrate 200 through a gold wire or a gold ribbon; wherein the diameter of the connecting portion 420 is 0.3mm-0.6mm, the height of the connecting portion 420 is 2.0mm-2.3mm, and the diameter of the through hole of the cavity plate 100 is greater than that of the connecting portion 420.

[0047] Specifically, the cavity plate 100 can be constructed as an irregular structure, the cavity plate 100 can be fixedly installed in the cavity of the module assembly through welding, so that the cavity of the module assembly can be divided into the high-frequency cavity and the low-frequency cavity, and electromagnetic isolation and shielding of the high-frequency circuit and the low-frequency circuit can be realized.

[0048] The high-frequency soft substrate 200 can be fixedly installed in the high-frequency cavity through a glue curing mode, the soft substrate has the advantages of stable dielectric constant and small signal transmission loss, and is particularly suitable for transmission of high-frequency microwave signals.

[0049] The low-frequency PCB 300 can be fixedly installed in the low-frequency cavity through a welding sintering mode, a traditional PCB has low cost and can meet the processing requirements of low-frequency digital or power signals.

[0050] The stepped metal pin 400 can be constructed as a stepped cylindrical structure, the surface of the stepped metal pin 400 can be gold-plated, so that the subsequent bonding connection of the high-frequency soft substrate 200 through the gold wire or the gold ribbon is facilitated. The stepped metal pin 400 comprises the stepped portion 410 and the connecting portion 420, the stepped portion 410 can be fixedly connected with the low-frequency PCB 300; the connecting portion 420 can be arranged in the high-frequency cavity and connected with the high-frequency soft substrate 200 through the gold wire or the gold ribbon.

[0051] It should be noted that the low-frequency PCB 300 is provided with a via hole matched with the stepped metal pin 400, the through hole matched with the stepped metal pin 400 is provided on the cavity plate 100 and the high-frequency soft substrate 200, the via hole and the through hole are coaxially arranged, and the diameters of the via hole and the through hole are greater than the diameter of the connecting portion 420 of the stepped metal pin 400. In this way, when the stepped metal pin 400 passes through the via hole and the through hole in sequence, an annular gap can be formed between the connecting portion 420 and the via hole and the through hole, so that direct contact between the via hole and the through hole of the stepped metal pin 400 is avoided during assembly, thereby preventing short circuit.

[0052] The stepped metal pin 400 is used to vertically connect the low-frequency PCB 300 and the high-frequency soft substrate 200, so that the shortest connection between the low-frequency PCB 300 and the high-frequency soft substrate 200 is realized, the radio frequency transmission characteristics of the high-frequency signal are significantly improved, and the Ku band 17.5 GHz can be used.

[0053] According to simulation and process, the diameter of the connecting portion 420 is 0.3mm-0.6mm, and is preferably 0.44mm; the height of the connecting portion 420 is 2.0mm-2.3mm, and is preferably 2.1mm. It should be noted that the connecting portion 420 can protrude from the high-frequency soft substrate 200 by a distance of 0.2mm, so that the connecting portion 420 and the high-frequency soft substrate 200 can be connected by gold wire or gold ribbon bonding. The diameter of the stepped portion 410 is 0.8mm, and the height of the stepped portion 410 is 0.6mm.

[0054] According to the characteristic impedance formula of the radio frequency coaxial line , is the characteristic impedance of the radio frequency coaxial line, is the dielectric constant of the medium, D is the inner diameter of the outer conductor, and d is the diameter of the inner conductor.

[0055] In the embodiment of the application, is a standard impedance of 50Ω; the size of the through hole of the cavity plate 100 at the stepped metal pin 400 is 1mm, that is, D is 1mm; the air is between the outer layer of the coaxial line and the stepped metal pin 400, and the dielectric constant of the air is about 1. The above values are substituted into the characteristic impedance formula of the radio frequency coaxial line to calculate that d is about 0.43mm, that is, the diameter of the connecting portion 420 is 0.43mm. In order to meet the processing precision requirement and save the manufacturing cost, the stepped metal pin 400 with the diameter of the connecting portion 420 close to 0.43mm in the prior art is selected, that is, the diameter of the connecting portion 420 of the stepped metal pin 400 is 0.44mm.

[0056] Please continue to see Figure 6As shown, the diameter of the connecting portion 420 is 0.44 mm, which is substituted into the AppCAD software, and the coaxial line outer diameter is calculated to be 1.012 mm, that is, the diameter of the through hole of the cavity plate 100 is 1.012 mm, which is close to the design value of 1 mm; the impedance value calculated by the AppCAD software is 49.2 ohms, which is very close to the characteristic impedance of 50 ohms of the radio frequency transmission line, so that the signal reflection loss can be effectively reduced, and the integrity of the radio frequency signal transmission is improved.

[0057] In the embodiment of the present application, the thickness of the low-frequency PCB board 300 can be 1 mm, the thickness of the cavity plate 100 can be 0.7 mm, the thickness of the high-frequency soft substrate 200 can be 0.127 mm, and the height difference between the top layer of the high-frequency soft substrate 200 and the top end of the connecting portion 420 can be 0.2 mm to 0.5 mm, so as to facilitate the subsequent bonding of the high-frequency soft substrate 200 and the connecting portion 420 by gold wire or gold ribbon. According to the shortest principle of gold wire bonding, the length of the connecting portion 420 can be selected to be 2.1 mm.

[0058] In the embodiment of the present application, the hole pad inner diameter of the low-frequency PCB board 300 at the stepped metal pin 400 is 0.5 mm, and the outer diameter is 1 mm. The connecting portion 420 can easily pass through the inner hole of the hole pad, and the diameter of the stepped portion 410 can be 0.8 mm, which is between the inner diameter and the outer diameter of the hole pad, so as to realize the axial positioning of the stepped metal pin 400, avoid excessive insertion, and also reserve sufficient flow space for subsequent soldering, ensuring the reliability of welding. The height of the stepped portion 410 can be 0.6 mm, so as to cooperate with the outer diameter of the solder pad, and the solder can naturally form a certain slope structure after welding. By such arrangement, not only the contact area of the solder with the stepped metal pin 400 and the hole pad can be increased, but also the mechanical stress can be effectively dispersed, avoiding the problem of solder cracking caused by cold and hot cycles or external forces, and significantly improving the long-term reliability of welding.

[0059] The soft connection of the high-frequency soft substrate 200 and the stepped metal pin 400 by gold wire or gold ribbon can effectively absorb and release stress under high and low temperature cycles and impact vibration conditions, fundamentally avoiding the risk of broken pins or solder pad falling caused by hard connection, thereby significantly improving the reliability of the connection between the high-frequency soft substrate 200 and the low-frequency PCB board 300. At the same time, the soft connection also reduces the dependence on the thickness of the cavity in the sintering process of the insulator, so that the cavity design can be thinned, and the miniaturization and light weight of the entire module assembly can be realized.

[0060] In the microwave radio frequency module provided in the embodiment of the present application, the vertical interconnection of the low-frequency PCB 300 and the high-frequency soft substrate 200 is realized through the stepped metal pin 400, and the connection reliability of the microwave radio frequency module is improved together by the soft connection structure formed by the gold wire or gold ribbon. Specifically, the stepped metal pin 400 realizes the shortest path transmission of the high-frequency signal between the low-frequency PCB 300 and the high-frequency soft substrate 200, effectively ensuring the stable operation of the radio frequency characteristics in the Ku band (such as 17.5 GHz); at the same time, the soft connection structure can actively absorb and release stress under the conditions of high-low temperature cycle and mechanical vibration, thereby avoiding the problems of pin breakage or pad falling off caused by the traditional hard connection mode. The two work together to ensure the complete transmission of the high-frequency signal while enhancing the reliability of the connection, thereby significantly improving the long-term reliability of the microwave radio frequency module in a complex environment.

[0061] Please continue to see Figure 4 As shown in the figure, the number of the stepped metal pins 400 corresponds to the number of the chip soldering pins of the high-frequency soft substrate 200.

[0062] It should be noted that the number of the stepped metal pins 400 can be multiple, and the number of the stepped metal pins 400 can correspond to the number of the chip soldering pins of the high-frequency soft substrate 200. In this way, it can be ensured that each signal is transmitted through the shortest independent path, greatly reducing the path length of the signal on the transmission line and the loss and delay caused thereby. In the embodiment of the present application, the number of the stepped metal pins 400 is 8. By determining the diameter and height of the connecting part 420 through simulation, the continuity and matching of the entire signal path impedance can be realized, the reflection loss is reduced to the minimum, the shortest connection of the signal is realized, and the radio frequency transmission characteristics of the high-frequency signal are improved, and the Ku band 17.5 GHz can be worked.

[0063] Among them, the signal path can be from the high-frequency soft substrate 200 to the gold wire or gold ribbon, then to the connecting part 420, then to the stepped part 410, and finally to the low-frequency PCB 300.

[0064] Please continue to see Figure 1 and Figure 4 As shown in the figure, according to one embodiment of the present application, the distribution position of the stepped metal pin 400 corresponds to the distribution position of the lead pad of the high-frequency soft substrate 200.

[0065] Specifically, the stepped metal pin 400 can be distributed inside the module assembly in a position corresponding to the position of the lead pads of the high-frequency soft substrate 200. Since the connecting portion 420 of the stepped metal pin 400 corresponds to the position of the lead pads of the high-frequency soft substrate 200, the gold wire bonding or gold ribbon bonding path between the two can be made as short as possible, thereby effectively improving the high-frequency cutoff frequency of the high-frequency signal, reducing the distortion of the rising and falling edges of the signal, and reducing the transmission loss of the high-frequency signal. The vertical distribution of the stepped metal pin 400 can effectively reduce the wiring space of the high-frequency soft substrate 200 and the low-frequency PCB 300 itself, significantly reduce the wiring complexity inside the module assembly, and greatly reduce the volume of the module assembly.

[0066] Please continue to see Figure 5 As shown, according to another embodiment of the present application, the electrical connection between the connecting portion 420 and the lead pads of the high-frequency soft substrate 200 adopts a gold wire, and the diameter of the gold wire is 25 μm.

[0067] Specifically, the gold wire has good electrical conductivity and low resistivity, which enables it to reduce signal loss at high frequencies. The 25 μm gold wire has smaller parasitic capacitance and parasitic inductance than thicker gold wires (such as 50 μm gold wires). When combined with the stepped metal pin 400 and the bonding length is controlled to be the shortest, the impedance discontinuity and energy reflection on the signal path can be minimized, thereby significantly improving the integrity and stability of high-frequency signal transmission.

[0068] Please continue to see Figure 5 As shown, according to another embodiment of the present application, the electrical connection between the connecting portion 420 and the lead pads of the high-frequency soft substrate 200 adopts a first gold ribbon or a second gold ribbon, wherein the width of the first gold ribbon is 150 μm and the thickness is 12.5 μm, and the width of the second gold ribbon is 300 μm and the thickness is 25 μm.

[0069] Specifically, the electrical connection between the connecting portion 420 and the lead pads of the high-frequency soft substrate 200 can be realized by using a gold ribbon. To meet the electrical and mechanical performance requirements of different circuit connections, the present application preferably provides two specifications of gold ribbons: a first gold ribbon with a width of 150 μm and a thickness of 12.5 μm; and a second gold ribbon with a width of 300 μm and a thickness of 25 μm.

[0070] For small-current signal pins or space-limited fine pads, the first gold ribbon with a smaller cross-sectional area can be used to achieve high-precision bonding and reduce parasitic parameters; for power supply or large-current path connection points that require high current-carrying capacity, the second gold ribbon with a larger cross-sectional area can be used to ensure the reliability of electrical connection.

[0071] Correspondingly, the bonding process parameters of the two gold ribbons need to be matched with their physical properties. Specifically, since the first gold ribbon has smaller volume and mass, the required bonding ultrasonic pressure and action time thereof are slightly smaller than those of the second gold ribbon, so as to avoid damage to the bonding interface and the high-frequency soft substrate itself while realizing reliable interconnection.

[0072] The assembly method of the microwave radio frequency module according to the embodiment of the application comprises: fixing and installing the high-frequency soft substrate 200 in the high-frequency cavity of the module assembly cavity, and fixing and installing the low-frequency PCB 300 in the low-frequency cavity of the module assembly cavity; making the stepped metal pin 400 pass through the low-frequency PCB 300 and the partition plate 100 in sequence and extend into the high-frequency cavity, so that the stepped part 410 is fixedly connected with the low-frequency PCB 300, and the connecting part 420 is located in the high-frequency cavity; connecting the connecting part 420 and the lead pad of the high-frequency soft substrate 200 through a gold wire or a gold ribbon, so as to form a transition soft connection between the low-frequency PCB 300 and the high-frequency soft substrate 200; wherein the diameter of the connecting part 420 is 0.3mm-0.6mm, the height of the connecting part 420 is 2.0mm-2.3mm, and the diameters of the through holes of the partition plate 100 and the high-frequency soft substrate 200 are greater than the diameter of the connecting part 420.

[0073] Specifically, the high-frequency soft substrate 200 is fixedly installed in the high-frequency cavity in the module assembly cavity by means of adhesive curing. The adhesive used can be low-temperature adhesive, for example, H20E conductive silver adhesive. The H20E conductive silver adhesive can provide very strong adhesive strength after curing, so that the high-frequency soft substrate 200 can be fixedly installed in the high-frequency cavity, preventing displacement or falling of the high-frequency soft substrate 200 in harsh environments such as vibration and impact, so as to ensure the connection stability of the high-frequency soft substrate 200.

[0074] The low-frequency cavity area in the module assembly cavity is applied with flux, four small pieces of tin sheet 153 are placed, the assembled low-frequency PCB 300 is placed in the low-frequency cavity and placed on a metal pressing block, and sintering is performed on a heating table at 160℃, so that the low-frequency PCB 300 can be fixedly installed in the low-frequency cavity of the module assembly cavity.

[0075] The stepped metal pin 400 passes through the low-frequency PCB 300, the partition plate 100 and the high-frequency soft substrate 200 in sequence, at this time, the stepped part 410 of the stepped metal pin 400 is in the low-frequency cavity. The stepped part 410 is firmly welded with the via pad of the low-frequency PCB 300 by using 183 solder, so as to support the weight of the entire stepped metal pin 400 and the bonding pressure during subsequent gold wire bonding of the high-frequency soft substrate 200 and the connecting part 420.

[0076] On the high-frequency soft substrate 200 surface, the lead bonding pad of the high-frequency soft substrate 200 is bonded to the connecting part 420 of the stepped metal pin 400 by using a gold wire or a gold tape, and is then coated with H20E conductive silver adhesive, and then placed in a high-temperature oven at 120°C for baking for 2 hours for solidification.

[0077] By connecting the connecting part 420 of the stepped metal pin 400 and the lead bonding pad of the high-frequency soft substrate 200 by using a gold wire or a gold tape, a transition soft connection can be formed between the low-frequency PCB 300 and the high-frequency soft substrate 200, so that stress can be fully released under high and low temperature and impact vibration conditions, and the phenomenon of pin breakage caused by hard connection between the high-frequency soft substrate 200 and the low-frequency PCB 300 is avoided, which leads to the falling off of the high-frequency soft substrate 200 and the low-frequency PCB 300, and thus the reliability of the connection between the high-frequency soft substrate 200 and the low-frequency PCB 300 can be greatly improved.

[0078] According to an optional embodiment of the present application, the fixed connection between the stepped part 410 and the low-frequency PCB 300 is welding.

[0079] Specifically, first, flux is accurately coated in the low-frequency cavity of the module cavity, and then four small pieces of tin sheet 153 are placed; then the assembled low-frequency PCB 300 is accurately placed into the low-frequency cavity, and a metal pressing block is placed above it; finally, the entire assembly is moved to a heating table at 160°C for sintering to complete reliable welding.

[0080] According to a further embodiment of the present application, the connecting part 420 and the lead bonding pad of the high-frequency soft substrate 200 are connected by a gold wire, and the diameter of the gold wire is 25μm.

[0081] In an optional mode of the present application, the connecting part 420 and the lead bonding pad of the high-frequency soft substrate 200 are connected by a first gold tape or a second gold tape, wherein the width of the first gold tape is 150μm and the thickness is 12.5μm, and the width of the second gold tape is 300μm and the thickness is 25μm.

[0082] In some examples of the present application, a pressing block is applied in the high-frequency cavity to keep the fit during the fixing of the high-frequency soft substrate 200, and is solidified at 120°C for about 2 hours.

[0083] Specifically, the shape of the pressing block can be consistent with the high-frequency soft substrate 200. When fixing the high-frequency soft substrate 200, the mounting surface of the high-frequency soft substrate 200 is uniformly coated with low-temperature glue, and is placed in the high-frequency cavity of the module assembly. At this time, the pressing block can be placed on the high-frequency soft substrate 200 to apply a certain pressure to it, so as to ensure that the substrate is tightly fitted with the bottom surface of the cavity, and effectively eliminates the residual bubbles between the interfaces; finally, the entire module assembly is moved into a high-temperature oven, and is solidified at 120°C for 2 hours, so that the glue layer is fully hardened, thereby realizing the stable and reliable installation of the high-frequency soft substrate 200.

[0084] Please continue to see Figure 7 As shown, dB(S(1, 1)) represents the input end return loss, generally the input end return loss of Ku band should be ≤-10dB, corresponding to the standing wave ratio is ≤1.92; dB(S(2, 2)) represents the output end return loss, generally the output end return loss of Ku band should be ≤-10dB, corresponding to the standing wave ratio is ≤1.92; dB(S(2, 1)) represents the transmission loss, the transmission loss reflects the attenuation degree of the signal from the input end to the output end, the smaller the value is, the better, that is, the closer to 0dB is better. Therefore, it can be known that the input end return loss and the output end return loss of the stepped metal pin 400 in the radio frequency transmission both meet the index of “≤-10dB”, the signal reflection is small, the matching performance is good; the transmission loss is extremely small, and the signal transmission efficiency is very high.

[0085] Other configurations of the microwave radio frequency module and the assembling method thereof according to the embodiments of the present application, such as welding, cementing and the like, and operations are known to those skilled in the art, and will not be described in detail here.

[0086] In the description of the present specification, the description of the terms “one embodiment”, “some embodiments”, “exemplary embodiment”, “example”, “specific example” or “some examples” and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0087] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A microwave radio module, characterized by include: A partition plate that divides the module assembly cavity into independent high-frequency cavities and low-frequency cavities; A high-frequency flexible substrate and a low-frequency PCB board, wherein the high-frequency flexible substrate is disposed in the high-frequency cavity and the low-frequency PCB board is disposed in the low-frequency cavity; A stepped metal pin, the stepped metal pin including a stepped portion located on the low-frequency cavity side and a connecting portion located in the high-frequency cavity; The low-frequency PCB board is provided with a through hole that mates with the stepped metal pin, and the cavity plate and the high-frequency flexible substrate are provided with a through hole that mates with the stepped metal pin. The stepped metal pin passes through the through hole and the through hole in sequence. The stepped part is fixedly connected to the low-frequency PCB board, and the connecting part is connected to the high-frequency flexible substrate by gold wire or gold strip. The diameter of the connecting part is 0.3mm to 0.6mm, the height of the connecting part is 2.0mm to 2.3mm, and the diameter of the through hole of the cavity plate and the high-frequency flexible substrate is larger than the diameter of the connecting part.

2. The microwave radio module of claim 1, wherein, The number of stepped metal pins corresponds to the number of chip soldering pins on the high-frequency flexible substrate.

3. The microwave radio module according to claim 1 or 2, c h a r a c t e r i z e d by The distribution of the stepped metal pins corresponds to the distribution of the lead pads on the high-frequency flexible substrate.

4. The microwave radio module of claim 1, wherein, The electrical connection between the connecting part and the lead pad of the high-frequency flexible substrate is made of gold wire, and the diameter of the gold wire is 25μm.

5. The microwave radio module of claim 1, wherein, The electrical connection between the connecting portion and the lead pads of the high-frequency flexible substrate is achieved using a first gold strip or a second gold strip, wherein the first gold strip has a width of 150 μm and a thickness of 12.5 μm, and the second gold strip has a width of 300 μm and a thickness of 25 μm.

6. A method of assembling a microwave radio module, characterized by, include: A high-frequency flexible substrate is fixedly installed in the high-frequency cavity of the module component cavity, and a low-frequency PCB board is fixedly installed in the low-frequency cavity of the module component cavity. The stepped metal pins are passed sequentially through the low-frequency PCB board and the cavity plate and extended into the high-frequency cavity, so that the stepped part is fixedly connected to the low-frequency PCB board and the connection part is located in the high-frequency cavity. The connecting portion is connected to the lead pads of the high-frequency flexible substrate by gold wire or gold strip, thereby forming a transitional soft connection between the low-frequency PCB board and the high-frequency flexible substrate. The diameter of the connecting part is 0.3mm to 0.6mm, the height of the connecting part is 2.0mm to 2.3mm, and the diameter of the through hole of the cavity plate and the high-frequency flexible substrate is larger than the diameter of the connecting part.

7. The method of assembly of claim 6, wherein, The step portion is fixedly connected to the low-frequency PCB board by welding.

8. The method of assembly of claim 6, wherein, The connection portion is connected to the lead pad of the high-frequency flexible substrate by a gold wire, and the diameter of the gold wire is 25μm.

9. The method of assembly of claim 6, wherein, The connection portion is connected to the lead pads of the high-frequency flexible substrate via a first gold strip or a second gold strip, wherein the first gold strip has a width of 150 μm and a thickness of 12.5 μm, and the second gold strip has a width of 300 μm and a thickness of 25 μm.

10. The method of assembly of claim 6, wherein, During the fixation process of the high-frequency flexible substrate, a pressure block is applied inside the high-frequency cavity to maintain adhesion, and the substrate is cured at 120°C for 2 hours.

Images