Novel terahertz circuit transition structure based on ball grid array

Abstract

The invention relates to a novel terahertz circuit transition structure based on a ball grid array, and belongs to the technical field of terahertz frequency band communication. And the inverted probe is transited and vertically interconnected with the chip through the BGA solder balls to realize waveguide-transition structure-chip signal conversion. According to the BGA vertical interconnection structure, gold wire jumper wire connection or conductive adhesive bonding is not needed, good packaging consistency is achieved, the yield of batch production is greatly improved, the production cost is reduced, the metalized waveguide block for restraining a higher-order mode is added into the suspension cavity, the solder balls are distributed in a triangular mode, and the reliability of the BGA vertical interconnection structure is improved. The transition performance and the thermal matching performance are improved, the reliability is higher, the solder balls are matched with the multi-branch suspended microstrip circuit to realize excellent broadband characteristics, and the insertion loss is smaller; the terahertz high-frequency module packaging structure can be applied to packaging of various terahertz high-frequency modules and has wider practicability.

Description

Technical Field

[0001] The invention belongs to the technical field of terahertz frequency band communication and relates to a novel terahertz circuit transition structure based on a ball grid array. Background Art

[0002] RF channels are core components of communication satellites, imaging and detection satellites, remote sensing satellites, etc. With the rapid development of semiconductor technology and advanced packaging technology, the demand for aerospace applications in the terahertz frequency band, especially 220GHz, is becoming increasingly clear, and the application requirements are becoming more urgent. In traditional terahertz RF circuits, gold wire or gold ribbon bonding is used to interconnect RF signals between semiconductor chips and between semiconductor chips and RF circuit boards. The transition circuit from waveguide to microstrip realizes the signal conversion from waveguide to transition structure to chip through gold wire bonding from waveguide-microstrip transition probe to coplanar waveguide. The conversion interconnection discontinuity introduced by this gold wire bonding connection method increases with the increase of application frequency. Especially in the high-frequency band, the transition circuit of the gold wire bonding connection method can no longer guarantee good signal transmission performance, which is mainly manifested in increased loss and severe signal reflection. In addition, due to the extremely small size of the terahertz chip itself, the transition structure of the gold wire bonding cannot guarantee good assembly repeatability and consistency.

[0003] Faced with the problem that traditional hybrid integration technology cannot achieve a good RF signal transition, the current terahertz band replacement gold wire solution is very limited. The use of monolithic antenna radiation or coupling to achieve the transition from the horizontal transmission line to the rectangular waveguide, but the use of antennas will be restricted by bandwidth and loss. In addition, the antenna has higher and more complex requirements for the monolithic process, and this method is not suitable for all process lines. Similarly, some scholars have proposed the use of conductive silver glue to bond the inverted suspended microstrip to the chip circuit for interconnection, but this method uses a suspended microstrip cavity with high-order modes, which affects the bandwidth performance. More importantly, the terahertz chip has a small pad size and a narrow gap between the RF and ground pads. In the assembly, the position of the artificial silver glue is inaccurate, the amount of conductive glue is uncontrollable, and the conductive glue itself is easy to diffuse during the high-temperature baking and solidification process, which will cause the transition structure and the monolithic circuit connection mismatch loss to increase, posing a huge threat to the yield rate. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a new terahertz circuit transition structure based on a ball grid array, which has good packaging consistency, greatly improves the yield of mass production, reduces production costs, improves transition performance and thermal matching performance, and has higher reliability.

[0005] The solution of the present invention is:

[0006] A new terahertz circuit transition structure based on ball grid array, including input rectangular waveguide, E-plane waveguide microstrip probe, waveguide probe-50 ohm suspended microstrip matching transition structure, multi-branch suspended microstrip matching structure, coplanar waveguide signal line, suspended cavity structure, chip circuit shielding cavity, 2 metalized waveguide blocks, coplanar waveguide, 2 metal microstrips and vertically interconnected BGA solder balls;

[0007] Among them, the input rectangular waveguide is placed vertically; one end of the E-plane waveguide microstrip probe is horizontally extended from the side of the input rectangular waveguide; the other end of the E-plane waveguide microstrip probe is suspended; the waveguide probe-50 ohm suspension microstrip matching transition structure and the multi-branch suspension microstrip matching structure are etched in the middle of the bottom surface of the E-plane waveguide microstrip probe and are connected in sequence; one end of the suspension cavity structure is horizontally connected to the side wall of the input rectangular waveguide; the chip circuit shielding cavity is horizontally coaxially connected to the other end of the suspension cavity structure; the suspended end of the E-plane waveguide microstrip probe passes through the suspension cavity structure and extends into the chip circuit shielding cavity; two metal microstrips are symmetrically and parallelly arranged at the waveguide probe-50 The invention discloses an ohmic suspended microstrip matching transition structure and a multi-branch suspended microstrip matching structure on both sides; a coplanar waveguide is arranged in a chip circuit shielding cavity; two metallized waveguide blocks are arranged in a suspension cavity structure; two metallized waveguide blocks are symmetrically arranged on both sides of the coplanar waveguide, and the two metallized waveguide blocks are located below the waveguide probe-50 ohm suspended microstrip matching transition structure and the multi-branch suspended microstrip matching structure; a coplanar waveguide signal line is located in the chip circuit shielding cavity and in the middle of the upper surface of the coplanar waveguide; vertically interconnected BGA solder balls are used to connect the metallized waveguide blocks and the metal microstrip, the multi-branch suspended microstrip matching structure and the coplanar waveguide signal line.

[0008] In the above-mentioned novel terahertz circuit transition structure based on ball grid array, the edge of the E-plane waveguide microstrip probe extending into one end of the input rectangular waveguide coincides with the center line of the narrow side of the input rectangular waveguide.

[0009] In the above-mentioned novel terahertz circuit transition structure based on ball grid array, the docking position of the suspended cavity structure and the input rectangular waveguide coincides with the first impedance transformation calibration line in the metal microstrip line of the waveguide probe-50 ohm suspended microstrip matching transition structure.

[0010] In the above-mentioned novel terahertz circuit transition structure based on ball grid array, the axial direction of the metal microstrip is parallel to the axial direction of the E-plane waveguide microstrip probe, and two metal microstrips are etched on the bottom surface of the E-plane waveguide microstrip probe.

[0011] In the above-mentioned new terahertz circuit transition structure based on ball grid array, the bottom of the metallized waveguide block and the suspended cavity structure are bonded by conductive silver glue, the two metallized waveguide blocks and the axial ends of the coplanar waveguide are bonded by conductive silver glue; the back side of the coplanar waveguide and the chip circuit shielding cavity are bonded by conductive silver glue.

[0012] In the above-mentioned novel terahertz circuit transition structure based on ball grid array, the circuit substrate material of the coplanar waveguide is gallium arsenide; a coplanar waveguide grounding hole is provided on the coplanar waveguide, and the coplanar waveguide is connected to the ground through the coplanar waveguide grounding hole.

[0013] In the above-mentioned novel terahertz circuit transition structure based on ball grid array, the vertically interconnected BGA solder balls include 2 supporting solder balls and 1 cascade solder ball; each supporting solder ball realizes vertical connection between a corresponding group of metallized waveguide blocks and metal microstrips; the cascade solder ball realizes vertical interconnection between the multi-branch suspended microstrip matching structure and the coplanar waveguide signal line.

[0014] In the above-mentioned novel terahertz circuit transition structure based on the ball grid array, the coplanar waveguide characteristic impedance is achieved to be 50 ohms by adjusting the width of the coplanar waveguide signal line.

[0015] In the above-mentioned novel terahertz circuit transition structure based on ball grid array, the two supporting solder balls are symmetrically located on both sides to play a supporting role; the cascade solder ball and the two supporting solder balls are distributed in a triangular shape below the suspended E-plane waveguide microstrip probe.

[0016] In the above-mentioned novel terahertz circuit transition structure based on ball grid array, the diameters of the supporting solder balls and the cascade solder balls are both 0.05 mm, and the materials are tin-lead or lead-free tin-silver-copper mixed materials; a port is provided on the axial outer end side wall of the chip circuit shielding cavity; and the signal is output from the port.

[0017] The beneficial effects of the present invention compared with the prior art are:

[0018] (1) The present invention adopts vertical interconnection between BGA solder balls and chips, eliminating the discontinuity of radio frequency transmission caused by traditional gold wire structures in the terahertz wave frequency band, greatly reducing losses, and reducing the uncertainty of interconnection by gold wire bonding or conductive adhesive bonding, thereby improving the yield of mass production and enhancing packaging performance;

[0019] (2) The present invention suppresses the high-order modes of the cavity by adding a metalized waveguide block, thereby improving the transition performance. At the same time, the supporting inverted suspension substrate is fixed to the suspension microstrip cavity and provides a heat dissipation channel. The overall package transition design has good package consistency and reduces production costs.

[0020] (3) The present invention proposes that the BGA cascade solder balls and the supporting solder balls on both sides are distributed in a triangular structure, which not only plays a stabilizing role, but also the full BGA solder ball distribution can make the thermal stress of the suspension substrate at high and low temperatures balanced, avoiding the bending deformation of the suspension substrate due to uneven thermal stress, and has higher reliability;

[0021] (4) The present invention performs impedance matching through the transition between the BGA solder ball and the multi-branch suspended microstrip circuit, which can achieve excellent broadband characteristics and low transmission insertion loss, making it more suitable for terahertz high-frequency band applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A top view of the terahertz circuit transition structure of the present invention;

[0023] Figure 2 This is a front view of the terahertz circuit transition structure of the present invention;

[0024] Figure 3 This is a cross-sectional view of the terahertz circuit transition structure of the present invention;

[0025] Figure 4 Schematic diagram of the triangular distribution of vertically interconnected BGA solder balls of the present invention.

[0026] Figure 5 An S-parameter simulation diagram of a 220 GHz novel terahertz circuit transition structure provided in Example 1 of the present invention;

[0027] Figure 6 A comparison diagram of the main mode S21 of the transition structure with a metallized waveguide block and the transition structure without a metallized waveguide block provided in Example 1 of the present invention;

[0028] Figure 7 A comparison diagram of the sub-high mode S21 of a transition structure with a metallized waveguide block and a transition structure without a metallized waveguide block provided in Example 1 of the present invention;

[0029] Figure 8 220 GHz “back-to-back” package transition structure diagram provided for implementation example 2 of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the embodiments.

[0031] The present invention provides a novel terahertz circuit transition structure based on a ball grid array, which realizes the signal conversion of waveguide-transition structure-chip by vertically interconnecting the inverted probe transition with the chip through the BGA solder ball. The BGA vertical interconnection structure of the present invention does not need gold wire jumper connection or conductive adhesive bonding, has good packaging consistency, greatly improves the yield rate of mass production, and reduces production costs. In addition, the present invention adds a metallized waveguide block that suppresses high-order modes in the suspension cavity to make the solder balls triangularly distributed, improves the transition performance and thermal matching performance, and has higher reliability. The present invention matches the solder balls with a multi-branch suspension microstrip circuit to achieve excellent broadband characteristics and lower insertion loss. The present invention can be applied to various high-frequency module packaging of terahertz and has a wider range of practicality.

[0032] Terahertz circuit transition structure based on ball grid array, such as Figures 1 to 3 As shown, it specifically includes an input rectangular waveguide 1, an E-plane waveguide microstrip probe 2, a waveguide probe-50 ohm suspended microstrip matching transition structure 3, a multi-branch suspended microstrip matching structure 4, a coplanar waveguide signal line 5, a suspended cavity structure 7, a chip circuit shielding cavity 8, two metalized waveguide blocks 9, a coplanar waveguide 10, two metal microstrips 11 and vertically interconnected BGA solder balls 12. Among them, the input rectangular waveguide 1 is placed vertically; one end of the E-plane waveguide microstrip probe 2 extends horizontally from the side of the input rectangular waveguide 1; the other end of the E-plane waveguide microstrip probe 2 is suspended; the waveguide probe-50 ohm suspension microstrip matching transition structure 3 and the multi-branch suspension microstrip matching structure 4 are etched in the middle of the bottom surface of the E-plane waveguide microstrip probe 2 and are connected in sequence; one end of the suspension cavity structure 7 is horizontally docked with the side wall of the input rectangular waveguide 1; the chip circuit shielding cavity 8 is horizontally coaxially docked with the other end of the suspension cavity structure 7; the suspended end of the E-plane waveguide microstrip probe 2 passes through the suspension cavity structure 7 and extends into the chip circuit shielding cavity 8; two metal microstrips 11 are symmetrically and parallelly arranged in the waveguide probe-50 ohm suspension On both sides of the microstrip matching transition structure 3 and the multi-branch suspended microstrip matching structure 4; the coplanar waveguide 10 is arranged in the chip circuit shielding cavity 8; two metallized waveguide blocks 9 are arranged in the suspension cavity structure 7; the two metallized waveguide blocks 9 are symmetrically arranged on both sides of the coplanar waveguide 10, and the two metallized waveguide blocks 9 are located below the waveguide probe-50 ohm suspended microstrip matching transition structure 3 and the multi-branch suspended microstrip matching structure 4; the coplanar waveguide signal line 5 is located in the chip circuit shielding cavity 8, and is located in the middle of the upper surface of the coplanar waveguide 10; the vertically interconnected BGA solder balls 12 realize the connection between the metallized waveguide blocks 9 and the metal microstrip 11, the multi-branch suspended microstrip matching structure 4 and the coplanar waveguide signal line 5.

[0033] The edge of the E-plane waveguide microstrip probe 2 extending into one end of the input rectangular waveguide 1 coincides with the center line of the narrow side of the input rectangular waveguide 1 .

[0034] The docking position between the suspended cavity structure 7 and the input rectangular waveguide 1 coincides with the first impedance transformation calibration line in the metal microstrip line of the waveguide probe-50 ohm suspended microstrip matching transition structure 3 .

[0035] The axial direction of the metal microstrip 11 is parallel to the axial direction of the E-plane waveguide microstrip probe 2 , and two metal microstrips 11 are etched on the bottom surface of the E-plane waveguide microstrip probe 2 .

[0036] The bottom of the metallized waveguide block 9 and the suspended cavity structure 7 are bonded by a conductive silver glue 13 , and the two metallized waveguide blocks 9 and the axial ends of the coplanar waveguide 10 are bonded by a conductive silver glue 13 ; the back side of the coplanar waveguide 10 and the chip circuit shielding cavity 8 are bonded by a conductive silver glue 13 .

[0037] The circuit substrate material of the coplanar waveguide 10 is gallium arsenide; a coplanar waveguide grounding hole 6 is provided on the coplanar waveguide 10, and the coplanar waveguide 10 is connected to the ground through the coplanar waveguide grounding hole 6.

[0038] The vertically interconnected BGA solder balls 12 include two supporting solder balls and one cascade solder ball; each supporting solder ball realizes vertical connection between a corresponding set of metallized waveguide blocks 9 and metal microstrips 11; the cascade solder ball realizes vertical interconnection between the multi-branch suspended microstrip matching structure 4 and the coplanar waveguide signal line 5. The characteristic impedance of the coplanar waveguide 10 is 50 ohms by adjusting the width of the coplanar waveguide signal line 5.

[0039] like Figure 4 As shown, two supporting solder balls are symmetrically located on both sides to play a supporting role; the cascade solder ball and the two supporting solder balls are distributed in a triangle shape below the suspended E-plane waveguide microstrip probe 2. The diameter of the supporting solder ball and the cascade solder ball are both 0.05 mm, and the material is tin-lead or lead-free tin-silver-copper mixed material; the axial outer end side wall of the chip circuit shielding cavity 8 is provided with a port 14; the signal is output from the port 14.

[0040] Example 1

[0041] A new circuit transition based on BGA solder balls at 220GHz, as shown in the following example: Figure 1 , Figure 2 and Figure 3 As shown, the model mainly includes input rectangular waveguide 1, E-plane waveguide microstrip probe 2, waveguide probe-50 ohm suspended microstrip matching transition structure 3, multi-branch suspended microstrip matching structure 4, suspended cavity structure 7, chip circuit shielding cavity 8, metallized waveguide block 9, vertically interconnected BGA solder balls 12, coplanar waveguide 10 and other structures on the transmission path.

[0042] In this embodiment 1, the RF signal is input through a standard waveguide 1. The input waveguide adopts a WR-4 standard waveguide, whose length × width dimensions are 1.092mm*0.546m, and the cavity chamfer radius is 0.2mm. Waveguide microstrip probe coupling is achieved by inverted E-plane probe coupling. The probe microstrip line undergoes impedance transformation to a 50-ohm suspended microstrip, and the position of extending into the waveguide coincides with the first section impedance transformation calibration line. The entire microstrip dielectric substrate adopts a quartz dielectric substrate, which is placed in a suspended cavity in an inverted form. One end of the substrate is suspended in the waveguide as a probe for side coupling. The end of the microstrip dielectric substrate is located at the center of the narrow side of the cavity, and the center of the end is about 1 / 4 of the waveguide wavelength away from the waveguide short-circuit surface in the vertical direction; the other end is output in the form of a 50-ohm suspended microstrip. Two metal microstrips 11 are etched on both sides of the suspended microstrip transmission line to ensure connection with the metal solder balls 12 on both sides.

[0043] In this embodiment 1, metallized waveguide blocks 9 are added to both sides of the bottom of the suspension cavity. The height of the metallized waveguide blocks is consistent with the thickness of the circuit chip, and they are connected with the BGA solder balls on both sides to achieve interconnection. The chip circuit shielding cavity 8 can be consistent with the height of the suspension cavity 7, and the size will decrease as the frequency band increases; the coplanar waveguide chip circuit 10 is fixed in the cavity by applying conductive silver glue on the back, and the coplanar waveguide circuit substrate material is gallium arsenide; 6 is a grounding hole to ensure that the coplanar waveguide is connected to the ground, and 5 is a coplanar waveguide signal line, and the width is adjusted to ensure that the characteristic impedance of the coplanar waveguide is 50 ohms.

[0044] like Figure 3 As shown, in this embodiment 1, the BGA solder ball and the 50-ohm impedance coplanar waveguide can be vertically interconnected, the diameter of the BGA solder ball is 0.05 mm, and the material is tin-lead or lead-free tin-silver-copper mixed material; at the same time, a multi-level high-and low-impedance suspended microstrip structure 7 is introduced to match and offset the discontinuity caused by the cascade solder balls, and the microstrip size can be adjusted according to specific needs; the signal is finally output from the chip shielding cavity port 14.

[0045] In this case 1, the HFSS 3D electromagnetic field model is used to simulate and verify the interconnection performance. After optimizing the matching microstrip lines, the simulation results are as follows Figure 4 As shown, within the full frequency band of WR-4 (170GHz-260GHz), the overall insertion loss of the 220GHz waveguide-microstrip probe transition is better than 0.26dB, and the return loss is better than 20dB, which shows that it has excellent broadband transmission characteristics.

[0046] The simulation and comparative analysis of Example 1 and the transition model without the metallized waveguide block 9 were performed in the full frequency band of WR-4. Figure 5 and Figure 6 It can be seen that the metallized waveguide block model proposed in this case is added to the suspension cavity, which has better transmission loss in the full frequency band and can improve the suppression of the second-highest mode by 5dB to 10dB.

[0047] Example 2

[0048] Further verify the transition performance of this terahertz waveguide-suspension microstrip in the full frequency band of WR-4. Figure 8 As shown, two identical structures of Embodiment 1 are placed "back to back" to form a symmetrical structure, namely, a packaging structure of waveguide-suspension microstrip-coplanar waveguide-suspension microstrip-waveguide, and both the input and output waveguides use WR-4 standard waveguides.

[0049] The performance of the "back-to-back" conversion structure in Example 2 is simulated and verified. It can be seen from the simulation that the insertion loss in the same WR-4 full frequency band (170GHz-260GHz) is less than 0.3dB, and the port return loss can be better than 24dB, which also verifies that it has excellent broadband transmission characteristics.

[0050] The present invention proposes a new terahertz circuit transition structure based on ball grid array technology, which adopts vertical interconnection between BGA solder balls and chips, eliminates the discontinuity of radio frequency transmission caused by traditional gold wire structures in the terahertz wave frequency band, greatly reduces losses, and reduces the uncertainty of interconnection by gold wire bonding or conductive adhesive bonding, thereby improving the yield of mass production and enhancing packaging performance.

[0051] The present invention proposes a novel circuit transition structure in the terahertz frequency band, which suppresses the high-order modes of the cavity by adding a metallized waveguide block, thereby improving the transition performance. At the same time, the supporting inverted suspended substrate is fixed on the suspended microstrip cavity and provides a heat dissipation channel. The overall packaging transition design has good packaging consistency and reduces production costs.

[0052] The present invention proposes that the BGA cascade solder balls and the supporting solder balls on both sides are distributed in a triangular structure, which not only plays a stabilizing role, but also the full BGA solder ball distribution can balance the thermal stress of the suspended substrate at high and low temperatures, avoiding bending deformation of the suspended substrate due to uneven thermal stress, and has higher reliability.

[0053] The present invention proposes a new terahertz circuit transition structure based on ball grid array technology, which performs impedance matching through the transition between BGA solder balls and multi-branch suspended microstrip circuits, can achieve excellent broadband characteristics, and has low transmission insertion loss, making it more suitable for terahertz high-frequency band applications.

[0054] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A terahertz circuit transition structure based on a ball grid array, characterized in that: It includes an input rectangular waveguide (1), an E-plane waveguide microstrip probe (2), a waveguide probe-50 ohm suspended microstrip matching transition structure (3), a multi-branch suspended microstrip matching structure (4), a coplanar waveguide signal line (5), a suspended cavity structure (7), a chip circuit shielding cavity (8), two metalized waveguide blocks (9), a coplanar waveguide (10), two metal microstrips (11) and vertically interconnected BGA solder balls (12); The input rectangular waveguide (1) is placed vertically; one end of the E-plane waveguide microstrip probe (2) extends horizontally from the side of the input rectangular waveguide (1); the other end of the E-plane waveguide microstrip probe (2) is suspended; a waveguide probe-50 ohm suspension microstrip matching transition structure (3) and a multi-branch suspension microstrip matching structure (4) are etched in the middle of the bottom surface of the E-plane waveguide microstrip probe (2) and are connected in sequence; one end of the suspension cavity structure (7) is horizontally connected to the side wall of the input rectangular waveguide (1); the chip circuit shielding cavity (8) is horizontally connected to the other end of the suspension cavity structure (7) coaxially; the suspended end of the E-plane waveguide microstrip probe (2) passes through the suspension cavity structure (7) and extends into the chip circuit shielding cavity (8); two metal microstrips (11) are symmetrically and parallelly arranged on the waveguide probe-50 ohm suspension microstrip matching structure. The invention relates to a chip circuit shielding cavity (8) and a coplanar waveguide (10). The coplanar waveguide (10) is arranged in a chip circuit shielding cavity (8). Two metallized waveguide blocks (9) are arranged in a suspension cavity structure (7). The two metallized waveguide blocks (9) are symmetrically arranged on both sides of the coplanar waveguide (10), and the two metallized waveguide blocks (9) are located below the waveguide probe-50 ohm suspension microstrip matching transition structure (3) and the multi-branch suspension microstrip matching structure (4). The coplanar waveguide signal line (5) is located in the chip circuit shielding cavity (8) and is located in the middle of the upper surface of the coplanar waveguide (10). The vertically interconnected BGA solder balls (12) realize the connection between the metallized waveguide blocks (9) and the metal microstrip (11), the multi-branch suspension microstrip matching structure (4) and the coplanar waveguide signal line (5).

2. The terahertz circuit transition structure based on a ball grid array according to claim 1, characterized in that: The edge of the E-plane waveguide microstrip probe (2) extending into one end of the input rectangular waveguide (1) coincides with the center line of the narrow side of the input rectangular waveguide (1).

3. The terahertz circuit transition structure based on a ball grid array according to claim 1, characterized in that: The docking position of the suspended cavity structure (7) and the input rectangular waveguide (1) coincides with the first section of the impedance transformation calibration line in the metal microstrip line of the waveguide probe-50 ohm suspended microstrip matching transition structure (3).

4. The terahertz circuit transition structure based on a ball grid array according to claim 1, characterized in that: The axial direction of the metal microstrip (11) is parallel to the axial direction of the E-plane waveguide microstrip probe (2), and two metal microstrips (11) are etched on the bottom surface of the E-plane waveguide microstrip probe (2).

5. The terahertz circuit transition structure based on a ball grid array according to claim 1, characterized in that: The bottom of the metallized waveguide block (9) and the suspended cavity structure (7) are bonded by means of a conductive silver glue (13); the two metallized waveguide blocks (9) and the axial ends of the coplanar waveguide (10) are bonded by means of a conductive silver glue (13); and the back surface of the coplanar waveguide (10) and the chip circuit shielding cavity (8) are bonded by means of a conductive silver glue (13).

6. The terahertz circuit transition structure based on a ball grid array according to claim 1, characterized in that: The circuit substrate material of the coplanar waveguide (10) is gallium arsenide; a coplanar waveguide grounding hole (6) is provided on the coplanar waveguide (10), and the coplanar waveguide (10) is connected to the ground through the coplanar waveguide grounding hole (6).

7. The terahertz circuit transition structure based on a ball grid array according to claim 1, characterized in that: The vertically interconnected BGA solder balls (12) include two supporting solder balls and one cascading solder ball; each supporting solder ball realizes vertical connection between a corresponding group of metallized waveguide blocks (9) and a metal microstrip (11); and the cascading solder ball realizes vertical interconnection between a multi-branch suspended microstrip matching structure (4) and a coplanar waveguide signal line (5).

8. The terahertz circuit transition structure based on a ball grid array according to claim 7, characterized in that: The characteristic impedance of the coplanar waveguide (10) is achieved to be 50 ohms by adjusting the width of the coplanar waveguide signal line (5).

9. The terahertz circuit transition structure based on a ball grid array according to claim 7, characterized in that: The two supporting solder balls are symmetrically located on both sides and play a supporting role; the cascade solder ball and the two supporting solder balls are distributed in a triangular shape below the suspended E-plane waveguide microstrip probe (2).

10. The terahertz circuit transition structure based on a ball grid array according to claim 7, characterized in that: The diameters of the supporting solder balls and the cascade solder balls are both 0.05 mm, and the materials are tin-lead or lead-free tin-silver-copper mixed materials; the axial outer end side wall of the chip circuit shielding cavity (8) is provided with a port (14); The signal is output from port (14).

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