Vertical transition structure from grounded coplanar waveguide to rectangular waveguide

Abstract

The invention discloses a vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide, and relates to the technical field of system-in-package devices. The transition structure comprises a rectangular input waveguide, a PCB (Printed Circuit Board), a rectangular output waveguide and a BGA (Ball Grid Array) packaging microsystem; according to the transition structure, the transition structure integrated in a BGA packaging microsystem and BGA packaging and PCB windowing interconnection junction three-dimensional stacking integration are utilized, processing errors and post-matching caused by post-distribution design and discrete components are avoided, processing and assembling are convenient, electromagnetic field energy of a grounded coplanar waveguide is coupled into the BGA packaging, and the electromagnetic field energy of the grounded coplanar waveguide is coupled into the BGA packaging. According to the multi-dielectric-material vertical transmission method, the multi-dielectric-material vertical transmission is realized, high-density integration of a BGA packaging microsystem is easy to realize, and the multi-dielectric-material vertical transmission method has a good application prospect in the technical field of system-level packaging.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of system-in-package devices, in particular to a vertical transition structure of a ground coplanar waveguide to a rectangular waveguide. BACKGROUND

[0002] The interconnection technology is a core enabling technology in the system-in-package technology, in a millimeter wave integrated package microsystem, a vertical transition structure of a ground coplanar waveguide (GCPW) to a rectangular waveguide is a core hub connecting a planar circuit module and a space radiation system, and the performance directly determines the signal integrity and energy transmission efficiency of the microsystem. The barium titanate (BT)-polypropylene (PP) composite process becomes an ideal technical path for solving the high-frequency transition problem in a high-density integrated scene, with the advantages of adjustable dielectric parameters, strong processing compatibility and balanced cost-effectiveness. The integrated package microsystem realizes the high integration of radio frequency chips, passive elements, antennas and interconnection structures through the design of "multi-device co-packaging and multi-function integration", which puts forward strict requirements on the traditional transition structure far beyond the independent device. SUMMARY

[0003] The application aims to provide a vertical transition structure of a ground coplanar waveguide to a rectangular waveguide, which can realize high-frequency transmission, is simple to assemble and has small signal loss.

[0004] To solve the above technical problems, the technical scheme adopted by the application is: a vertical transition structure of a ground coplanar waveguide to a rectangular waveguide, comprising a rectangular input waveguide, a PCB board and a rectangular output waveguide, an input end opening window is formed on the left side of the PCB board, an output end opening window is formed on the right side of the PCB board, the rectangular input waveguide is connected with the input end opening window, the rectangular output waveguide is connected with the output end opening window, a BGA package microsystem is formed on the upper surface of the PCB board, a first transition structure is formed in the BGA package microsystem corresponding to the input end opening window, a second transition structure is formed in the BGA package microsystem corresponding to the output end opening window, a ground coplanar waveguide transmission line is formed on the surface of the BGA package microsystem, in the vertical distance, one end of the ground coplanar waveguide transmission line is located on the input end opening window, the other end of the ground coplanar waveguide transmission line is located on the output end opening window.

[0005] Further technical solutions are that the electromagnetic wave is transmitted by the rectangular input waveguide to the input end window formed by windowing and side wall metallization in the PCB board, then the electromagnetic wave enters the first transition structure integrated in the BGA packaging micro system, then the electromagnetic wave is transmitted by the ground coplanar waveguide transmission line on the surface of the BGA packaging micro system to the second transition structure of the BGA packaging micro system, then the electromagnetic wave is transmitted by the second transition structure to the output end window formed by windowing and side wall metallization in the PCB board, and finally the electromagnetic wave is output through the port of the rectangular output waveguide.

[0006] The beneficial effects generated by the above technical solutions are that the structure of the application uses the material characteristics of high integration of the BT-PP process between the waveguide and the ground coplanar waveguide, uses the packaging micro system to realize the transmission of the electromagnetic signal, uses the BGA packaging and the PCB windowing structure to realize the transmission of the electromagnetic signal, and uses the back-to-back structure to realize the measurement of the signal loss of the ground coplanar waveguide, and uses the packaging integrated transition structure to make up for the vacancy of the conventional wire bonding structure in high frequency. At the same time, the interconnection structure is integrated in the packaging to reduce the influence of subsequent processing and assembly errors on the system. This structure provides more choices when using W-band signal measurement and transmission, and reduces the assembly error and signal loss caused by the assembly of discrete component structures. BRIEF DESCRIPTION OF DRAWINGS

[0007] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0008] Figure 1 is a schematic diagram of the transition structure according to the embodiment of the application; Figure 2 is a schematic diagram of the transition structure according to the embodiment of the application without the rectangular input waveguide and the rectangular output waveguide; Figure 3 is a schematic diagram of the transition structure according to the embodiment of the application without part of the metal and the dielectric layer; Figure 4 is a schematic diagram of the transition structure according to the embodiment of the application without part of the metal and the dielectric layer on the basis of Figure 3 ; Figure 5 is a schematic diagram of the transmission of the transition structure according to the embodiment of the application in part of the W-band ; and DETAILED DESCRIPTION Among them: 1, rectangular input waveguide; 2, PCB board; 3, rectangular output waveguide; 4, input end window; 5, output end window; 6, BGA packaging micro system; 7, first transition structure; 8, second transition structure; 9, ground coplanar waveguide transmission line; 10, first radiation patch; 11, first matching patch; 12, second radiation patch; 13, second matching patch; 14, ground hole.

[0009] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0010] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0011] like Figures 1-4 As shown, this embodiment of the invention discloses a vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide. The transition structure includes a rectangular input waveguide 1, a PCB board 2, a rectangular output waveguide 3, and a BGA-packaged microsystem 6. The rectangular input waveguide 1 and the rectangular output waveguide 3 preferably use standard WR10 rectangular waveguides. An input window 4 is formed on the left side of the PCB board 2, and an output window 5 is formed on the right side of the PCB board 2. The sidewalls of the input window 4 and the output window 5 are metallized.

[0012] The rectangular input waveguide 1 is connected to the input window 4, and the rectangular output waveguide 3 is connected to the output window 5. A BGA packaged microsystem 6 is formed on the upper surface of the PCB board 2. A first transition structure 7 is formed in the BGA packaged microsystem 6 corresponding to the input window 4, and a second transition structure 8 is formed in the BGA packaged microsystem 6 corresponding to the output window 5. A grounded coplanar waveguide transmission line 9 is formed on the surface of the BGA packaged microsystem 6. In terms of vertical distance, one end of the grounded coplanar waveguide transmission line 9 is located on the input window 4, and the other end of the grounded coplanar waveguide transmission line 9 is located on the output window 5.

[0013] Preferably, the grounded coplanar waveguide transmission line 9 has a signal line width of 59µm, a slot spacing of 50µm on both sides, a thickness of 15µm, and a back-to-back structure length of 2mm.

[0014] The BT-PP integrated BGA packaged microsystem 6 employs a stacked design of 7 dielectric layers and 8 metal layers. An isolation groove is provided between the ground coplanar waveguide transmission line 9 and the top metal layer, preventing the ground coplanar waveguide transmission line 9 from contacting the top metal layer. The distribution of different metal layers and the via-formed cavities achieve a transition structure design within the packaged microsystem. The microsystem package uses a BGA as its external interconnect structure. The overall transition structure design of the packaged microsystem vertically transitions the ground coplanar waveguide signal on the BGA package surface to the lower waveguide-like structure formed by the PCB and BGA package solder balls. The electromagnetic signal is constrained by the BGA solder ball distribution and the PCB material with windowed and sidewall metallized treatment, thus transmitting it to the standard WR10 waveguide structure.

[0015] Electromagnetic waves are input through a rectangular input waveguide 1, and transmitted to a waveguide-like transmission structure (input window 4) formed by the windowed metallization of the BGA packaged microsystem 6 and the PCB board. From there, the waves are transmitted through a multi-layered composite transition structure within the BGA packaged microsystem to the grounded coplanar waveguide transmission line 9 on the upper surface of the BGA packaged microsystem, achieving single-end transmission. On the other side, the energy transmitted from the grounded coplanar waveguide transmission line 9 is transferred to the vertical transition BGA package on the other side. From there, the energy is transmitted through the transition structure within the BGA package to the transmission structure formed by the PCB board and BGA solder balls, ultimately reaching the waveguide structure. This achieves same-waveguide transmission of electromagnetic energy, which is then transmitted through the transition structure to the grounded coplanar waveguide structure. A double-ended symmetrical back-to-back structure is used to calculate the energy loss of the grounded coplanar waveguide structure. The grounded coplanar waveguide enables customized design for different signal bands, achieving ease of use.

[0016] The system employs a vertical stacking of three materials: BGA packaged microsystem, PCB, and metal waveguide. The stacking involves integrating the metal waveguide and the BT-PP process-designed microsystem through an intermediate PCB structure. The BGA packaged microsystem is directly transmitted to the underlying metal waveguide after being windowed and metallized on the PCB, thereby reducing interconnection losses and improving the overall system consistency design.

[0017] Furthermore, such as Figure 3 and Figure 4As shown, the first transition structure 7 includes a first radiating patch 10 located on the left side of the BGA packaged microsystem. The first radiating patch 10 is disposed opposite to the input terminal opening window 4, and the first radiating patch 10 is located on a metal layer between the bottommost metal layer and the topmost metal layer. The outer periphery of the first radiating patch 10 is isolated from this metal layer by a dielectric. A first mating patch 11 is formed on a metal layer above the first radiating patch 10 and below the topmost metal layer. The outer periphery of the first mating patch 11 is isolated from this metal layer by a dielectric. In the vertical direction, the first radiating patch 10 and the first mating patch 11 are arranged in a cross shape.

[0018] Furthermore, such as Figure 3 and Figure 4 As shown, the second transition structure 8 includes a second radiating patch 12 located on the right side of the BGA packaged microsystem. The second radiating patch 12 is disposed opposite to the output window 5, and the second radiating patch 12 is located on the metal layer between the bottommost metal layer and the topmost metal layer. The outer periphery of the second radiating patch 12 is isolated from the metal layer by a dielectric. A second mating patch 13 is formed on a metal layer above the second radiating patch 12 and below the topmost metal layer. The outer periphery of the second mating patch 13 is isolated from the metal layer by a dielectric. In the vertical direction, the second radiating patch 12 and the second mating patch 13 are arranged in a cross shape.

[0019] Furthermore, such as Figure 1 And such as 3 and Figure 4 As shown, a plurality of grounding holes 14 are formed on the outer periphery of the first transition structure 7, the outer periphery of the second transition structure 8, and the outer periphery of the grounded coplanar waveguide transmission line 9. The grounding holes 14 are metallized vias that penetrate the dielectric layer in the BGA packaged microsystem 6.

[0020] In the BGA packaged microsystem 6, the BT-PP material used is a 100µm thick core board material. The surface metal thickness of the core board bonding sheet is 20µm, and the PP material thickness is 30µm. The transition structure from the surface GCPW structure to the inner package adopts an internal double-layer surface mount design and a matching method of layer metal distribution to achieve a good transition effect. In order to prevent electromagnetic signal leakage, a dielectric filling cavity is formed by metal vias before the metal layer distribution to achieve electromagnetic signal constraint. In the double-surface mount design of the matching structure, the main function of the upper surface mount is to achieve a good matching effect with the upper metal layer distribution, while the lower metal surface mount can improve the overall matching performance.

[0021] The signal input structure is a rectangular waveguide, which is rigidly connected to the PCB material as shown in the figure. After connection, the signal is transmitted to the transition structure in the BGA packaged microsystem using BT-PP technology through the PCB windowed metallized structure. The PCB windowed metallized structure is consistent with the standard WR10 waveguide structure, and the solder ball diameter in the BGA package is 100µm. By realizing a waveguide-like structure through PCB windowed metallization to confine electromagnetic energy, the electromagnetic energy can be transferred to the BGA packaged microsystem structure, thereby achieving a highly integrated three-dimensional vertical transition of the three materials: PCB, BT-PP, and metal rectangular waveguide.

[0022] refer to Figure 5 The present invention is illustrated in a partial W-band transmission diagram. It can be seen that, within the 92-97 GHz frequency range, the vertical transition structure from the grounded coplanar waveguide to the rectangular waveguide in the BT-PP process-integrated packaged microsystem achieves an isolation better than 15 dB. This structure can be applied to the W-band 92-94 GHz airport runway foreign object detection system, enabling high-density integration and integrated packaged microsystem design.

[0023] The transition structure described in this application employs a multi-layer metal distribution design and a metallized via-based cavity design to achieve electromagnetic signal constraint and a good transition effect. The multi-layer metal matching design utilizes a dual-surface matching design. The upper surface plate, located near the ground coplanar waveguide structure, serves as the matching surface plate to constrain the electromagnetic signal transmitted via GCPW. The lower surface plate acts as the radiating surface plate to achieve vertical transmission of the electromagnetic signal. Simultaneously, the main structure of the transition structure is designed within a BGA-packaged microsystem, achieving high-density integration. The solder ball array distribution inherent in BGA packaging is used as a waveguide-like structure to effectively constrain and transmit electromagnetic signals. The special design of the coplanar waveguide layer near the ground achieves the function of constraining and transmitting electromagnetic energy, thereby achieving lower energy loss transmission.

Claims

1. A vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide, characterized in that: The device includes a rectangular input waveguide (1), a PCB board (2), and a rectangular output waveguide (3). An input window (4) is formed on the left side of the PCB board (2), and an output window (5) is formed on the right side of the PCB board (2). The rectangular input waveguide (1) is connected to the input window (4), and the rectangular output waveguide (3) is connected to the output window (5). A BGA packaged microsystem (6) is formed on the upper surface of the PCB board (2). A first transition structure (7) is formed in the BGA packaged microsystem (6) corresponding to the input window (4), and a second transition structure (8) is formed in the BGA packaged microsystem (6) corresponding to the output window (5). A grounded coplanar waveguide transmission line (9) is formed on the surface of the BGA packaged microsystem (6). In terms of vertical distance, one end of the grounded coplanar waveguide transmission line (9) is located on the input window (4), and the other end of the grounded coplanar waveguide transmission line (9) is located on the output window (5).

2. The vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide as described in claim 1, characterized in that: The rectangular input waveguide (1) and the rectangular output waveguide (3) are standard WR10 rectangular waveguides.

3. The vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide as described in claim 1, characterized in that: The sidewalls of the input end window (4) and the output end window (5) are metallized.

4. The vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide as described in claim 1, characterized in that: The BGA packaged microsystem (6) includes six or more metal layers and a dielectric layer between the metal layers. An isolation groove is provided between the ground coplanar waveguide transmission line (9) and the top metal layer so that the ground coplanar waveguide transmission line (9) does not contact the top metal layer.

5. The vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide as described in claim 4, characterized in that: The BGA packaged microsystem (6) includes 7 dielectric layers and 8 metal layers.

6. The vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide as described in claim 4, characterized in that: The first transition structure (7) includes a first radiating patch (10) located on the left side of the BGA packaged microsystem. The first radiating patch (10) is disposed opposite to the input terminal opening window (4), and the first radiating patch (10) is located on the metal layer between the bottommost metal layer and the topmost metal layer. The outer periphery of the first radiating patch (10) is isolated from the metal layer by a medium. A first matching patch (11) is formed on a metal layer above the first radiating patch (10) and below the topmost metal layer. The outer periphery of the first matching patch (11) is isolated from the metal layer by a medium. In the vertical direction, the first radiating patch (10) and the first matching patch (11) are arranged in a cross shape.

7. The vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide as described in claim 4, characterized in that: The second transition structure (8) includes a second radiating patch (12) located on the right side of the BGA packaged microsystem. The second radiating patch (12) is disposed opposite to the output window (5), and the second radiating patch (12) is located on the metal layer between the bottommost metal layer and the topmost metal layer. The outer periphery of the second radiating patch (12) is isolated from the metal layer by a dielectric. A second matching patch (13) is formed on a metal layer above the second radiating patch (12) and below the topmost metal layer. The outer periphery of the second matching patch (13) is isolated from the metal layer by a dielectric. In the vertical direction, the second radiating patch (12) and the second matching patch (13) are arranged in a cross shape.

8. The vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide as described in claim 4, characterized in that: The electromagnetic wave is transmitted from the rectangular input waveguide (1) to the input window (4) formed by the opening and sidewall metallization in the PCB board (2), and then enters the waveguide-like cavity structure formed by the BGA solder balls in the BGA packaged microsystem. Then the electromagnetic wave enters the first transition structure (7) integrated in the BGA packaged microsystem (6), and then the electromagnetic wave is transmitted through the grounded coplanar waveguide transmission line (9) on the surface of the BGA packaged microsystem to the second transition structure (8) of the BGA packaged microsystem. Then the electromagnetic wave is transmitted from the second transition structure (8) to the output window (5) formed by the opening and sidewall metallization in the PCB board (2). Finally, the electromagnetic wave is output through the port of the rectangular output waveguide (3).

9. The vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide as described in claim 6, characterized in that: A plurality of grounding holes (14) are formed on the outer periphery of the first transition structure (7), the outer periphery of the second transition structure (8) and the outer periphery of the grounded coplanar waveguide transmission line (9). The grounding holes (14) are metallized vias that penetrate the dielectric layer in the BGA packaged microsystem (6).

10. The vertical transition structure from a grounded coplanar waveguide to a rectangular waveguide as described in claim 1, characterized in that: The BGA packaged microsystem (6), PCB board (2), rectangular input waveguide (1) and rectangular output waveguide (3) constitute a vertical stacked structure.

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