A vertical interconnection structure of a Ka-band radio frequency front-end module

Abstract

The present invention discloses a vertical interconnection structure of a Ka-band radio frequency front-end module, comprising: an upper substrate structure, a lower substrate structure, a plurality of BGA balls and a ground plane for connection; the upper substrate structure comprises an upper substrate, an input microstrip line, a gold wire, a T-section gradient structure, a coplanar waveguide, an upper substrate circular pad, an upper substrate grounding hole, an upper metal through-hole is provided below the upper substrate circular pad for conducting the coplanar waveguide and the BGA ball; an upper substrate butterfly pad is symmetrically provided on both sides of the upper metal through-hole; the lower substrate structure comprises a lower substrate, a lower substrate circular pad, a stripline, a lower metal through-hole, a lower substrate grounding hole, a lower metal through-hole for conducting the lower substrate circular pad and the stripline, and a lower substrate butterfly pad is symmetrically provided on both sides of the lower metal through-hole below the lower substrate circular pad. The present invention can reduce return loss and insertion loss in the Ka-band, reduce volume, and improve integration.

Description

Technical Field

[0001] The present invention belongs to the field of radio frequency, and in particular relates to a vertical interconnection structure of a Ka-band radio frequency front-end module. Background Art

[0002] With the urgent need for high integration, miniaturization, and lightweight RF front-end modules, system-in-package (SiP) technology has rapidly developed. However, discontinuities in RF interconnect signals can degrade circuit transmission characteristics and adversely affect RF front-end module performance. In millimeter-wave frequency band transmission structures, the structure and routing of multilayer dielectric board transmission lines are extremely delicate and dense, making the factors affecting transmission line performance and interconnect transitions complex. Vertical interconnection is key to achieving low-loss transmission of RF signals between multilayer dielectric boards and has a significant impact on overall system performance.

[0003] In this context, vertical interconnect transition technology has attracted widespread attention from researchers both domestically and internationally. Chinese Patent 1 (Patent Publication No. CN 117254230 A) proposes a vertical interconnect structure for three-dimensional integration of X-band RF front-ends. This vertical interconnect structure utilizes a ball grid array (BGA), but it operates only in the 8-9 GHz band, resulting in a narrow operating frequency bandwidth. Chinese Patent 2 (Patent Publication No. CN 113113375 A) proposes a vertical interconnect structure for millimeter-wave chip packaging. This involves multi-chip packaging and is complex and difficult to implement. Jia Lu et al. designed a novel Ka-band vertical interconnect structure that uses high-impedance transmission lines with inductive effects in a microstrip coaxial structure, grounded via a pad, to improve matching characteristics. This structure is innovative, but still exhibits significant losses. Foreign researchers have attempted to control the characteristic impedance of microstrips by varying the inductance and capacitance of the microstrip to mitigate the impedance inconsistencies caused by component sizes. However, this results in a narrow operating frequency band and significant losses. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a vertical interconnection structure of a Ka-band radio frequency front-end module. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] A vertical interconnection structure of a Ka-band radio frequency front-end module, comprising:

[0006] An upper substrate structure, a lower substrate structure, a plurality of BGA balls for connecting the upper substrate structure and the lower substrate structure, and a ground plane; wherein,

[0007] The upper substrate structure includes an upper substrate, an input microstrip line, a gold wire, a T-section gradient structure, a coplanar waveguide, and an upper substrate circular pad arranged on the upper surface of the upper substrate and connected in sequence. An upper metal through hole is provided below the upper substrate circular pad for conducting the coplanar waveguide and the BGA ball below the upper substrate structure; upper substrate butterfly pads are symmetrically provided on both sides of the upper metal through hole below the upper substrate circular pad; the upper substrate structure is also provided with an upper substrate grounding hole;

[0008] The lower substrate structure includes a lower substrate, a lower substrate circular pad arranged on the upper surface of the lower substrate and connected to the BGA ball, a strip line arranged inside the lower substrate, and a lower metal through-hole. The lower metal through-hole is used to conduct the lower substrate circular pad and the strip line, and lower substrate butterfly pads are symmetrically arranged on both sides of the lower metal through-hole below the lower substrate circular pad; the lower substrate structure is also provided with a lower substrate grounding hole.

[0009] In one embodiment of the present invention, the upper substrate is made of Al2O3, has a dielectric constant of 8.53, a tangent loss of 0.0011, and a thickness of 0.9 mm.

[0010] In one embodiment of the present invention, the width of the input microstrip line is 0.11 mm; the height of the gold wire is 0.2 mm, and the length of the gold wire is 0.27 mm; the width of the coplanar waveguide is 0.19 mm; the radius of the circular pad of the upper substrate is 0.22 mm; the radius of the upper metal through hole is 0.065 mm; and the radius of the upper substrate grounding hole is 0.0625 mm.

[0011] In one embodiment of the present invention, the T-shaped section gradient structure comprises:

[0012] The first section T-section, the second section T-section, and the third section T-section.

[0013] In one embodiment of the present invention, the transverse dimensions of the first T-section are x1=0.11 mm, y1=0.44 mm, and the longitudinal dimensions are x2=0.28 mm, y2=0.15 mm;

[0014] The transverse dimensions of the second T-shaped section are x3 = 0.12 mm, y3 = 0.27 mm, and the longitudinal dimensions are x4 = 0.4 mm, y4 = 0.12 mm;

[0015] The transverse dimensions of the third T-section are x5 = 0.07 mm, y5 = 0.21 mm, and the longitudinal dimensions are x6 = 0.23 mm, y6 = 0.07 mm;

[0016] The x direction is the signal transmission direction.

[0017] In one embodiment of the present invention, the radius of the multiple BGA balls is 0.225 mm, and the spacing is 0.8 mm.

[0018] In one embodiment of the present invention, the material of the lower substrate includes TSM-DS3, with a dielectric constant of 3 and a thickness of 1 mm.

[0019] In one embodiment of the present invention, the radius of the circular pad of the lower substrate is 0.4 mm; the width of the stripline is 0.2 mm; the radius of the lower metal through hole is 0.1 mm; and the radius of the lower substrate grounding hole is 0.1 mm.

[0020] In one embodiment of the present invention, the radius of the butterfly-shaped pads on the upper substrate is 0.14 mm, the included angle is 123°, and the spacing between the pads is 0.1 mm.

[0021] In one embodiment of the present invention, the radius of the butterfly-shaped pads of the lower substrate is 0.24 mm, the included angle is 164°, and the spacing between the pads is 0.127 mm.

[0022] Beneficial effects of the present invention:

[0023] The present invention improves on the traditional vertical interconnection technology and proposes a vertical interconnection structure for a Ka-band RF front-end module. The vertical interconnection is optimized to reduce parasitic effects and solve problems such as signal discontinuity caused by impedance mismatch. A T-shaped gradient structure is used for transition from the microstrip line to the coplanar waveguide in the metal through-hole, and a butterfly pad is installed on the metal signal through-hole. The butterfly pad is symmetrically located on both sides of the through-hole. Compared with the circular pad, the additional symmetry of the butterfly pad structure can improve the bandwidth. By adjusting the radius, width and angle of the butterfly pad to change the capacitance and inductance of the vertical transition, the bandwidth can be widened, the parasitic effects can be reduced, and good impedance matching can be obtained to achieve better transmission characteristics. At the same time, BGA (ball grid array) and metal through-holes are used as the inter-layer and intra-layer transition structures of the RF front-end module, and ground holes and pads are designed to improve the signal discontinuity between different transmission lines. The vertical interconnect structure of the present invention realizes the vertical transmission of RF signals from coplanar waveguide to stripline through intra-layer transition and inter-layer transition. Through the optimized design of BGA balls, pads, metal through-holes and transmission lines, the return loss and insertion loss of the RF front-end module can be reduced in the Ka band. The use of this vertical interconnect structure can also improve the integration of the RF front-end module. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A three-dimensional schematic diagram of the vertical interconnection structure of a Ka-band RF front-end module provided by an embodiment of the present invention;

[0025] FIG2( a ) is a side view of a vertical interconnect structure of a Ka-band RF front-end module according to an embodiment of the present invention;

[0026] FIG2( b ) is a plan view of a vertical interconnection structure of a Ka-band RF front-end module provided by an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of an upper substrate structure of a vertical interconnection structure of a Ka-band RF front-end module provided by an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of a lower substrate structure of a vertical interconnection structure of a Ka-band RF front-end module provided by an embodiment of the present invention;

[0029] Figure 5 It is the equivalent circuit model of vertical transmission of butterfly pad;

[0030] Figure 6 Schematic diagram of structural parameters of the T-shaped section gradient structure in an embodiment of the present invention;

[0031] Figure 7 Schematic diagram of the butterfly pad structure in an embodiment of the present invention;

[0032] Figure 8 A diagram showing simulation results of the vertical interconnection structure of the Ka-band RF front-end module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0034] In radio frequency communication systems, there are various radio frequency components. When a miniaturized, lightweight and integrated millimeter wave front-end module is required, vertical interconnection technology becomes a key technology in the module. The vertical interconnection structure can realize low-loss transmission of radio frequency signals between the upper and lower dielectric substrates. In addition, optimizing the design of the vertical interconnection structure can make the radio frequency front-end module more compact in physical size, which is conducive to the realization of high-density circuit integration. However, the existing vertical interconnection technology still faces challenges in high-frequency band applications. The main problems are large volume, high loss, narrow frequency band, and difficulty in integration, which leads to problems such as signal integrity and manufacturing cost. Therefore, the present invention aims to propose a vertical interconnection structure for a Ka-band radio frequency front-end module to realize vertical interconnection of upper and lower layers of planar circuits in the radio frequency front-end module, reduce the adverse effects on the volume and performance of the entire system, and achieve performance optimization.

[0035] Specifically, the embodiment of the present invention provides a vertical interconnection structure of a Ka-band RF front-end module, please refer to Figure 12 (a) shows a side view of the module vertical interconnection structure; and FIG2 (b) shows a plan view of the module vertical interconnection structure. Figure 3 The upper substrate structure shown, Figure 4 The lower substrate structure shown, the vertical interconnection structure of the Ka-band RF front-end module may include:

[0036] An upper substrate structure, a lower substrate structure, a plurality of BGA balls for connecting the upper substrate structure and the lower substrate structure, and a ground plane; wherein,

[0037] The upper substrate structure includes an upper substrate, an input microstrip line, a gold wire, a T-section gradient structure, a coplanar waveguide, and an upper substrate circular pad arranged on the upper surface of the upper substrate and connected in sequence. An upper metal through hole is provided below the upper substrate circular pad for conducting the coplanar waveguide and the BGA ball below the upper substrate structure; upper substrate butterfly pads are symmetrically provided on both sides of the upper metal through hole below the upper substrate circular pad; the upper substrate structure is also provided with an upper substrate grounding hole;

[0038] The lower substrate structure includes a lower substrate, a lower substrate circular pad arranged on the upper surface of the lower substrate and connected to the BGA ball, a strip line arranged inside the lower substrate, and a lower metal through-hole. The lower metal through-hole is used to conduct the lower substrate circular pad and the strip line, and lower substrate butterfly pads are symmetrically arranged on both sides of the lower metal through-hole below the lower substrate circular pad; the lower substrate structure is also provided with a lower substrate grounding hole.

[0039] See also Figure 1 It can be understood that the upper substrate structure and the lower substrate structure are connected through several BGA balls. The BGA balls serve as interlayer transitions to achieve vertical transmission of RF signals between the upper substrate and the lower substrate, and provide support for the upper substrate and the lower substrate.

[0040] In an optional embodiment, the material of the upper substrate is Al2O3, and the material of the lower substrate includes TSM-DS3.

[0041] The planar schematic diagram of the vertical interconnection structure is shown in Figure 2, where 1 represents the input microstrip line, 2 represents the gold wire, 3 to 5 represent the T-section gradient structure, 6 represents the coplanar waveguide, 7 represents the circular pad of the upper substrate, 8 represents the ground hole of the upper substrate, 9 represents the ground plane, and 10 represents the ground hole of the lower substrate.

[0042] Exemplarily, a three-segment T-shaped gradient structure is employed between the gold wire and the coplanar waveguide. Specifically, in an embodiment of the present invention, the T-shaped gradient structure comprises a first T-shaped segment, a second T-shaped segment, and a third T-shaped segment. The T-shaped gradient structure enables vertical signal transmission from the microstrip line of the upper substrate to the interlayer, thereby reducing RF signal loss.

[0043] For upper substrate structure, please refer to Figure 3 , where 11 represents the butterfly pad of the upper substrate, 12 represents the BGA ball, and 13 represents the upper metal through-hole; the upper substrate structure is provided with an intra-layer transition, and the coplanar waveguide on the upper surface of the upper substrate and the BGA ball on the lower surface are connected through the intra-layer transition metal through-hole (i.e., the upper metal through-hole), thereby realizing vertical transmission of signals between the upper and lower surfaces of the upper substrate.

[0044] The lower substrate structure is shown in Figure 4 , where 14 represents the lower metal through-hole, 15 represents the strip line, 16 represents the circular pad of the lower substrate, and 17 represents the butterfly pad of the lower substrate; the lower substrate structure is also provided with an intra-layer transition, through which the pads on the upper surface of the lower substrate and the strip lines in the layer are connected through the intra-layer transition metal through-hole (i.e., the lower metal through-hole), thereby realizing vertical transmission of signals between the upper surface of the lower substrate and the layer.

[0045] The vertical interconnection structure of the embodiment of the present invention realizes the vertical transmission of RF signals from microstrip line to stripline through T-shaped section gradient structure, metal through-hole and BGA ball. By designing the T-shaped section gradient structure, BGA ball, solder pad, metal through-hole and transmission line, the return loss and insertion loss of the RF front-end module can be reduced. The use of this vertical interconnection structure can also improve the integration of the RF front-end module.

[0046] Specifically, the strip-to-coaxial transition is the main structure of vertical interconnection, which has an impact on the performance of the RF module. With the increase of frequency, especially in the millimeter wave band, the discontinuity between the transmission line and the vertical interconnection through-hole increases, which will reduce the transmission characteristics of the circuit. Based on the equivalent model of the strip-to-coaxial transition, the present invention designs a butterfly pad vertical interconnection structure suitable for the Ka band. Using HFSS (high-frequency electromagnetic simulation software) for modeling and simulation, its transmission characteristics meet the requirements of low insertion loss and low reflection within the bandwidth. According to the characteristics of the vertical transition structure, it can be equivalent to a lumped parameter model, such as Figure 5 As shown, Figure 5 It is the equivalent circuit model of vertical transmission of butterfly pad.

[0047] In this model, L s is the equivalent inductance of the lower metal through hole, Cb is the capacitance between the lower metal through hole and the ground, Ca is the capacitance between the lower substrate butterfly pad and the ground, CL is the equivalent capacitance between the butterfly pads, R sis the series insertion loss of the lower metal via. The above parameters can be obtained from the following formula.

[0048]

[0049] In formulas (1) to (5), R DC is the DC resistance of the lower metal through hole, δ is the skin depth of the through hole, μ0 is the vacuum permeability, μ r is the relative permeability of the inner conductor material, ε0 and ε r is the dielectric constant of vacuum and PCB. R is the radius of the butterfly pad, r is the radius of the underlying metal via, s is the distance between the butterfly pads, and h is the distance from the butterfly pad to ground. The metal vias and the surrounding ground vias form a structure similar to a coaxial line. The equivalent circuit model and the above formula show that the strip-coaxial-quasi-connected circuit in millimeter-wave circuits can be equivalent to a lossy low-pass network. Each parasitic parameter will vary with frequency. Based on the above analysis, the vertical strip-coaxial interconnect can be viewed as an impedance matching problem for two different transmission modes. Butterfly pads are installed on the metal signal via, symmetrically located on either side of the via. Compared to circular pads, the additional symmetry of the butterfly pad structure can improve bandwidth. By adjusting the radius, width, and angle of the butterfly pad to modify the capacitance and inductance of the vertical transition, the bandwidth can be widened, parasitic effects can be reduced, and good impedance matching can be achieved, resulting in better transmission characteristics.

[0050] The following is a simulation experiment data of the vertical interconnection structure of the Ka-band RF front-end module as a specific implementation method.

[0051] The upper substrate is made of Al2O3, has a dielectric constant of 8.53, a tangent loss of 0.0011, and a thickness of 0.9 mm.

[0052] The width of the input microstrip line is 0.11 mm; the height of the gold wire is 0.2 mm, the length of the gold wire is 0.27 mm; the width of the coplanar waveguide is 0.19 mm (see Figure 6 mx); the radius of the circular pad of the upper substrate is 0.22mm (see Figure 6 r1); the radius of the upper metal through hole is 0.065mm; the radius of the upper substrate ground hole is 0.0625mm.

[0053] The radius of the multiple BGA balls is 0.225 mm, and the spacing is 0.8 mm.

[0054] The material of the lower substrate includes TSM-DS3, with a dielectric constant of 3 and a thickness of 1 mm.

[0055] The radius of the circular pad of the lower substrate is 0.4 mm; the width of the strip line is 0.2 mm; the radius of the lower metal through hole is 0.1 mm; and the radius of the lower substrate grounding hole is 0.1 mm.

[0056] The characteristic impedance of the input microstrip line, coplanar waveguide and stripline is 50 ohms.

[0057] The specific parameters of the T-section gradient structure obtained through simulation optimization are shown in Figure 6 , specifically:

[0058] The transverse dimensions of the first T-shaped section are x1 = 0.11 mm, y1 = 0.44 mm, and the longitudinal dimensions are x2 = 0.28 mm, y2 = 0.15 mm;

[0059] The transverse dimensions of the second T-shaped section are x3 = 0.12 mm, y3 = 0.27 mm, and the longitudinal dimensions are x4 = 0.4 mm, y4 = 0.12 mm;

[0060] The transverse dimensions of the third T-section are x5 = 0.07 mm, y5 = 0.21 mm, and the longitudinal dimensions are x6 = 0.23 mm, y6 = 0.07 mm;

[0061] The x direction is the signal transmission direction.

[0062] The embodiment of the present invention optimizes the design of a three-segment T-section gradient structure for coplanar waveguides, which has lower loss and better impedance matching, providing broad space for chip applications and making this technology a viable option for millimeter wave systems.

[0063] The butterfly pad structure designed in the embodiment of the present invention is as follows Figure 7 As shown, specifically:

[0064] The radius of the butterfly-shaped pads on the upper substrate is 0.14 mm, the included angle is 123°, and the spacing between the pads is 0.1 mm.

[0065] The radius of the butterfly-shaped pads of the lower substrate is 0.24 mm, the included angle is 164°, and the spacing between the pads is 0.127 mm.

[0066] Among them, the radius of the substrate butterfly pad is Figure 7 R is used to represent the angle, and θ is used to represent the angle. Figure 7 The r in the figure represents the radius of the circular pad.

[0067] In this embodiment of the present invention, butterfly pads are installed on metal signal vias, symmetrically located on either side of the via. Compared to circular pads, the additional symmetry of the butterfly pad structure can improve bandwidth. By adjusting the radius, width, and angle of the butterfly pad to change the capacitance and inductance of the vertical transition, bandwidth can be widened, parasitic effects can be reduced, and good impedance matching can be achieved, resulting in better transmission characteristics.

[0068] In an embodiment of the present invention, in the millimeter wave frequency band, vertical interconnection is achieved between dielectric substrates of different materials and different thicknesses. BGA solder balls with a quasi-coaxial structure are used for inter-layer transition, and metal through-holes with a quasi-coaxial structure are used for intra-layer transition to vertically transmit signals. Metal shielding ground holes are arranged on both sides of the planar transmission line and around the metal through-holes, so that the vertical interconnection structure has low loss and good transmission performance.

[0069] The simulation results of the vertical interconnection structure of the Ka-band RF front-end module of the embodiment of the present invention are as follows: Figure 8 As shown, from Figure 8 It can be seen that within the Ka band, its return loss is better than 17dB and its insertion loss is better than 0.27dB, showing good performance.

[0070] There is still room for improvement in the existing technology in terms of operating frequency bandwidth, transmission loss, signal continuity, etc. The present invention improves on the traditional vertical interconnection technology and proposes a vertical interconnection structure for a Ka-band RF front-end module. The vertical interconnection is optimized to reduce parasitic effects and solve problems such as signal discontinuity caused by impedance mismatch. A T-shaped gradient structure is used for transition from the microstrip line to the coplanar waveguide in the metal through-hole, and butterfly pads are installed in the metal signal through-hole. The butterfly pads are symmetrically located on both sides of the through-hole. Compared with the circular pad, the additional symmetry of the butterfly pad structure can improve the bandwidth. By adjusting the radius, width and angle of the butterfly pad to change the capacitance and inductance of the vertical transition, the bandwidth can be widened, parasitic effects can be reduced, and good impedance matching can be obtained to achieve better transmission characteristics. At the same time, BGA (ball grid array) and metal through-holes are used as the inter-layer and intra-layer transition structures of the RF front-end module, and ground holes and pads are designed to improve the signal discontinuity between different transmission lines. The vertical interconnect structure of the present invention realizes the vertical transmission of RF signals from coplanar waveguide to stripline through intra-layer transition and inter-layer transition. Through the design of BGA balls, pads, metal through-holes and transmission lines, the return loss and insertion loss of the RF front-end module can be reduced in the Ka band. The use of this vertical interconnect structure can also improve the integration of the RF front-end module.

[0071] Specifically, the present invention has the following beneficial effects:

[0072] 1. The vertical interconnection structure realizes the vertical transmission of RF signals from coplanar waveguide to stripline through the metal through-holes in the layer and the BGA balls between the layers. The return loss and insertion loss are reduced by the BGA with short traces, the metal ground holes with coaxial structure and the RF through-holes with butterfly pads. The use of three-dimensional integrated vertical interconnection structure can also reduce the volume of the RF front-end module and improve the integration of the RF front-end module.

[0073] 2. Using a quasi-coaxial structure for BGA solder ball arrangement and metal ground holes, the more adjacent shielding solder balls and metal ground holes there are and the closer they are, the more they tend to be in a coaxial form. The external shielding solder balls and ground holes can guide the external electric field to the ground to prevent it from entering the transmission solder balls and metal through-holes and interfering with the RF signal transmission. This can not only bind and shield the electromagnetic field, but also suppress parasitic high-order modes caused by discontinuous excitation of the electromagnetic field.

[0074] 3. Optimizing the coplanar waveguide design, a three-segment T-section gradient structure was designed to better achieve impedance matching from the gold wire to the coplanar waveguide. In practical applications, this interconnection adds a specifically structured T-section as a matching network from the chip to the coplanar waveguide, which is then mounted on a standard chip pad via a bonding structure. This solution provides a low-loss, low-cost interconnect, opening up broad opportunities for chip applications and making this technology a viable option for millimeter-wave systems.

[0075] 4. Install butterfly pads on the metal signal vias, symmetrically located on either side of the via. Compared to circular pads, the additional symmetry of the butterfly pad structure can improve bandwidth. By adjusting the radius, width, and angle of the butterfly pad to change the capacitance and inductance of the vertical transition, bandwidth can be widened, parasitic effects can be reduced, and good impedance matching can be achieved, resulting in better transmission characteristics.

[0076] 5. The vertical interconnection structure disclosed in the present invention, on the basis of achieving the above-mentioned beneficial effects, has good return loss and insertion loss in the Ka band, and has a simple structure and fewer design parameters, and can be widely used in RF front-end modules.

[0077] It should be noted that, in the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 invention.

[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0079] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A vertical interconnection structure of a Ka-band radio frequency front-end module, characterized in that: include: An upper substrate structure, a lower substrate structure, a plurality of BGA balls for connecting the upper substrate structure and the lower substrate structure, and a ground plane; wherein, The upper substrate structure includes an upper substrate, an input microstrip line, a gold wire, a T-section gradient structure, a coplanar waveguide, and an upper substrate circular pad arranged on the upper surface of the upper substrate and connected in sequence. An upper metal through hole is provided below the upper substrate circular pad for conducting the coplanar waveguide and the BGA ball below the upper substrate structure; upper substrate butterfly pads are symmetrically provided on both sides of the upper metal through hole below the upper substrate circular pad; the upper substrate structure is also provided with an upper substrate grounding hole; The lower substrate structure includes a lower substrate, a lower substrate circular pad arranged on the upper surface of the lower substrate and connected to the BGA ball, a strip line arranged inside the lower substrate, and a lower metal through-hole. The lower metal through-hole is used to conduct the lower substrate circular pad and the strip line, and lower substrate butterfly pads are symmetrically arranged on both sides of the lower metal through-hole below the lower substrate circular pad; the lower substrate structure is also provided with a lower substrate grounding hole.

2. The vertical interconnect structure of the Ka-band RF front-end module according to claim 1, characterized in that: The upper substrate is made of Al2O3, has a dielectric constant of 8.53, a tangent loss of 0.0011, and a thickness of 0.9 mm.

3. The vertical interconnection structure of the Ka-band RF front-end module according to claim 1, characterized in that: The width of the input microstrip line is 0.11 mm; the height of the gold wire is 0.2 mm, and the length of the gold wire is 0.27 mm; the width of the coplanar waveguide is 0.19 mm; the radius of the circular pad of the upper substrate is 0.22 mm; the radius of the upper metal through hole is 0.065 mm; and the radius of the upper substrate grounding hole is 0.0625 mm.

4. The vertical interconnect structure of the Ka-band RF front-end module according to claim 1, wherein: The T-shaped section gradient structure comprises: The first section T-section, the second section T-section, and the third section T-section.

5. The vertical interconnection structure of the Ka-band RF front-end module according to claim 4, characterized in that: The transverse dimensions of the first T-shaped section are x1 = 0.11 mm, y1 = 0.44 mm, and the longitudinal dimensions are x2 = 0.28 mm, y2 = 0.15 mm; The transverse dimensions of the second T-shaped section are x3 = 0.12 mm, y3 = 0.27 mm, and the longitudinal dimensions are x4 = 0.4 mm, y4 = 0.12 mm; The transverse dimensions of the third T-section are x5 = 0.07 mm, y5 = 0.21 mm, and the longitudinal dimensions are x6 = 0.23 mm, y6 = 0.07 mm; The x direction is the signal transmission direction.

6. The vertical interconnect structure of the Ka-band RF front-end module according to claim 1, wherein: The radius of the multiple BGA balls is 0.225 mm, and the spacing is 0.8 mm.

7. The vertical interconnection structure of the Ka-band RF front-end module according to claim 1, characterized in that: The material of the lower substrate includes TSM-DS3, with a dielectric constant of 3 and a thickness of 1 mm.

8. The vertical interconnect structure of the Ka-band RF front-end module according to claim 1, wherein: The radius of the circular pad of the lower substrate is 0.4 mm; the width of the strip line is 0.2 mm; the radius of the lower metal through hole is 0.1 mm; and the radius of the lower substrate grounding hole is 0.1 mm.

9. The vertical interconnection structure of the Ka-band RF front-end module according to claim 1, wherein: The radius of the butterfly-shaped pads on the upper substrate is 0.14 mm, the included angle is 123°, and the spacing between the pads is 0.1 mm.

10. The vertical interconnection structure of the Ka-band RF front-end module according to claim 1, wherein: The radius of the butterfly-shaped pads of the lower substrate is 0.24 mm, the included angle is 164°, and the spacing between the pads is 0.127 mm.

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