Waveguide-to-microstrip transition device suitable for high-frequency broadband

Abstract

The invention provides a waveguide-to-microstrip transition device suitable for a high-frequency broadband. The waveguide-to-microstrip transition device comprises a back-to-back structure body, a waveguide cover plate, a step table structure, an upper cover plate, glass beads, a radio frequency printed board, a cavity matching unit and an impedance adjusting structure. The invention provides a novel waveguide-to-microstrip transition structure. According to a separated waveguide, a standard waveguide is separated along a wide side surface, so that welding of a step table structure and a glass bead is facilitated; the step structure is an independent structure and is welded on the wide side of the standard waveguide to form a ridge waveguide, and welding holes are respectively reserved in the side surface and the top surface of the step structure and are used for welding a conductor in a glass bead; the glass bead is sequentially welded with the integral structure, the step structure and the microstrip line printed board, and a cavity is reserved between the welded glass bead and the microstrip line for matching, so that a novel separated waveguide-step structure-glass bead-cavity matching-microstrip transition structure is formed. A simulation result shows that the return loss of the transition structure in the frequency band range of 78GHz-104GHz is superior to-20dB, and the insertion loss is superior to 0.1 dB.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical components, and particularly relates to a device for waveguide-to-microstrip transition suitable for high-frequency broadband. Background Art

[0002] As the operating frequency of radio frequency circuits gets higher and higher, the transmission lines between radio frequency components gradually change from microstrip lines of planar circuits to waveguide transmission lines of three-dimensional circuits. Consequently, the waveguide-to-microstrip transition becomes more difficult to design as the operating frequency increases. Conventional waveguide-ridge waveguide-microstrip line structures, waveguide-fin line-microstrip structures, and waveguide-probe-microstrip structures cannot simultaneously solve problems such as low cost, easy assembly, airtightness, and wide bandwidth. Therefore, a waveguide-to-microstrip transition structure suitable for high-frequency broadband needs to be designed. The literature "W-Band Waveguide-Microstrip Transition Design and Tolerance Analysis, Vol. 39, No. 6, 2018" achieved an insertion loss of less than 0.34 dB and a return loss of greater than 17.5 dB in the waveguide-microstrip structure within the range of 75 GHz to 110 GHz by optimizing the matching structure on the microstrip line. However, this structure cannot achieve airtightness, limiting its applicable scenarios. The literature "Design of Power Combining Amplifier with Airtight Structure in W Band, Vol. 7, No. 49, 2023" achieved an airtight transition structure with an insertion loss of less than -1.2 dB and a return loss of less than -20 dB within the range of 90 GHz to 96 GHz by welding a molybdenum-copper carrier carrying a silicon-based conversion chip to the waveguide port. However, this transition structure requires customized silicon-based chips and has high process assembly requirements, thus bringing problems such as high cost and low efficiency.

[0003] Although the above-mentioned literature has realized the design of the W-band waveguide-to-microstrip transition structure, it cannot simultaneously meet the requirements of low cost, easy assembly, airtightness, and wide bandwidth of the transition structure. Summary of the Invention

[0004] The present invention aims to solve the problem that the existing W-band waveguide-to-microstrip transition structure cannot simultaneously meet the requirements of low cost, easy assembly, airtightness, and wide bandwidth, and provides a device for waveguide-to-microstrip transition suitable for high-frequency broadband. The present invention is a novel separated waveguide-step platform structure-bead-cavity matching-microstrip transition structure; this transition structure realizes excellent performances such as low cost, low loss, ultra-wideband, airtightness, and suitability for mass production based on the separated waveguide structure, ridge waveguide matching, cavity matching, and airtight welding process.

[0005] The present invention provides a device for waveguide-to-microstrip transition applicable to high-frequency broadband, including a back-to-back structure body, waveguide covers connected to the upper parts of both ends of the back-to-back structure body, stepped platform structures connected to both ends of the top of the back-to-back structure body, an upper cover located between the waveguide covers and hermetically connected to the top of the back-to-back structure body, a bead, a radio frequency printed circuit board sequentially connected to the stepped platform structure, a cavity matching located between the bead and the radio frequency printed circuit board, and an impedance adjustment structure connected between the top of the stepped platform structure and the bead. The numbers of the waveguide covers, the stepped platform structures, the beads, the cavity matching, and the impedance adjustment structures are all 2;

[0006] The stepped platform structure is a ridge waveguide, which forms a conversion structure from a standard waveguide to a ridge waveguide with the back-to-back structure body to perform the first impedance transformation; after the stepped platform structure is welded to the bead, it forms an impedance adjustment structure to perform the second broadband matching; the cavity matching is the third matching, which matches the device for waveguide-to-microstrip transition to the characteristic impedance of a standard microstrip line.

[0007] For the device for waveguide-to-microstrip transition applicable to high-frequency broadband according to the present invention, as a preferred mode, the stepped platform structure is a three-stage ridge waveguide structure, which performs impedance transformation in the frequency band of 78 GHz - 104 GHz. The impedance adjustment structure converts the TE10 mode of the waveguide into the TEM mode of the coaxial line to perform the transition from the waveguide to the bead; finally, the conversion from the TEM mode to the quasi-TEM mode is completed through the cavity matching.

[0008] For the device for waveguide-to-microstrip transition applicable to high-frequency broadband according to the present invention, as a preferred mode, the back-to-back structure body is an integrally formed structure symmetric about the center;

[0009] The back-to-back structure body includes a block body, stepped platform structure installation grooves connected to both ends of the center of the top of the block body and extending downward, bead installation holes, radio frequency printed circuit board installation grooves sequentially located on one side of the stepped platform structure installation grooves, and a frame connected to the upper surface of the block body and enclosing the radio frequency printed circuit board installation groove inside. The numbers of the stepped platform structure installation grooves and the bead installation holes are both 2. The bead installation holes are located on both sides of the radio frequency printed circuit board installation groove. The frame is a hollow structure and extends downward to the block body in the middle of both sides. The bead installation holes are opened on both sides of the frame and extend in the left and right directions;

[0010] The stepped platform structure installation grooves are structures separated along the wide side of the standard waveguide. The bottom surfaces of the stepped platform structure installation grooves, the bead installation holes, and the radio frequency printed circuit board installation grooves have different heights;

[0011] The upper cover is laser welded inside the top of the frame.

[0012] A device for waveguide-to-microstrip transition applicable to high-frequency broadband. As a preferred embodiment, the stepped platform structure includes a stepped structure and a base connected to the bottom of the stepped structure. A base mounting groove for connecting to the base is provided at the bottom of the mounting groove of the stepped platform structure.

[0013] A device for waveguide-to-microstrip transition applicable to high-frequency broadband. As a preferred embodiment, the impedance adjustment structure is the fourth layer of steps connected to the top of the stepped platform structure. A bead outer conductor mounting groove extending in the left-right direction is provided inside the fourth layer of steps;

[0014] The second broadband matching is performed by adjusting the distance between the bead outer conductor and the impedance adjustment structure and the structural parameters of the impedance adjustment structure.

[0015] A device for waveguide-to-microstrip transition applicable to high-frequency broadband. As a preferred embodiment, the outer diameter of the bead is smaller than the narrow-side dimension of the standard waveguide to obtain a waveguide-bead end-fed structure in the W band.

[0016] A device for waveguide-to-microstrip transition applicable to high-frequency broadband. As a preferred embodiment, a through-tin hole is connected to the top of the stepped platform structure. After the inner conductor of the bead is inserted into the stepped platform structure, it is welded through the through-tin hole;

[0017] Solder holes are connected to the left and right sides of the bead mounting hole of the back-to-back structure body;

[0018] The device for waveguide-to-microstrip transition is a centrosymmetric structure. The waveguide cover plate is installed on the back-to-back structure body by screws.

[0019] A device for waveguide-to-microstrip transition applicable to high-frequency broadband. As a preferred embodiment, the standard waveguide is the standard waveguide WR-10 with a wide-side dimension of 2.54 mm and a narrow-side dimension of 1.27 mm;

[0020] The outer conductor diameter of the bead is 1.2 mm, the length is 1 mm, the inner conductor diameter is 0.15 mm, and the length is 2.6 mm;

[0021] The RF printed circuit board is a microwave flexible substrate with a dielectric constant of 2.2 and a thickness of 0.127 mm.

[0022] A device for waveguide-to-microstrip transition applicable to high-frequency broadband. As a preferred embodiment, the preparation method of the device for waveguide-to-microstrip transition includes the following steps:

[0023] S1. Weld the side surface of the stepped platform structure to the inner conductor of the bead. After welding, an impedance adjustment structure is formed, and then the stepped platform structure is welded to the back-to-back structure body;

[0024] S2. Solder the RF printed circuit board and the bead onto the back-to-back structure body. After soldering, a cavity matching is formed.

[0025] S3. After installing the waveguide cover plate and the upper cover plate, a back-to-back structure composed of a split waveguide - stepped platform structure - bead - cavity matching - microstrip is obtained, and a device for waveguide-to-microstrip transition applicable to high-frequency broadband is fabricated.

[0026] The present invention can achieve airtight conversion from waveguide circuits to microstrip circuits in the range of 78 GHz to 104 GHz, and is used in millimeter-wave band communication systems and radar systems.

[0027] The present invention designs a novel waveguide-to-microstrip transition structure composed of a split waveguide - stepped platform structure - bead - cavity matching - microstrip line: the split waveguide separates the standard waveguide along the broadside plane, facilitating the soldering of the stepped platform structure and the bead; the stepped platform structure is an independent structure, which forms a ridged waveguide after being soldered to the broadside of the standard waveguide. Welding holes are respectively provided on the side and top surfaces of the stepped platform structure for soldering the inner conductor of the bead. The bead is successively soldered to the overall structure, the stepped platform structure, and the microstrip printed circuit board. After soldering, a cavity matching is left between the bead and the microstrip line, thus forming a novel split waveguide - stepped platform structure - bead - cavity matching - microstrip transition structure. The simulation results of the present invention show that in the frequency band range of 78 GHz - 104 GHz, the return loss of the transition structure is better than -20 dB, and the insertion loss is better than 0.1 dB.

[0028] The present invention has the following advantages:

[0029] (1) The present invention has the characteristics of wide frequency band and low insertion loss. In the frequency band of 78 GHz - 104 GHz, the insertion loss is not greater than 0.1 dB, and the return loss is not greater than -20 dB, and it can be used in application scenarios such as low-noise amplifiers, power amplifiers, and power combining networks.

[0030] (2) While having excellent performance, the present invention also has an airtight characteristic, making it suitable for complex application environments such as ground, missile-borne, and space-borne.

[0031] (3) The present invention uses conventional materials and devices, is easy to process and assemble, and has the advantages of low cost and large-scale production. Description of the Drawings

[0032] Figure 1 It is a three-dimensional schematic diagram of a device for waveguide-to-microstrip transition applicable to high-frequency broadband;

[0033] Figure 2 It is a partial three-dimensional schematic diagram of a device for waveguide-to-microstrip transition applicable to high-frequency broadband;

[0034] Figure 3Cross-sectional view of the back-to-back structure of a device for waveguide-to-microstrip transition applicable to high-frequency broadband;

[0035] Figure 4 Partial three-dimensional schematic diagram of a device for waveguide-to-microstrip transition applicable to high-frequency broadband;

[0036] Figure 5 Insertion loss simulation diagram of a device for waveguide-to-microstrip transition applicable to high-frequency broadband;

[0037] Figure 6 Return loss simulation diagram of a device for waveguide-to-microstrip transition applicable to high-frequency broadband.

[0038] Reference numerals:

[0039] 1. Back-to-back structure body; 11. Block body; 12. Step structure mounting groove; 13. Glass bead mounting hole; 14. RF printed circuit board mounting groove; 15. Frame; 2. Waveguide cover plate; 3. Step structure; 4. Upper cover plate; 5. Glass bead; 6. RF printed circuit board; 7. Cavity matching; 8. Impedance adjustment structure; 9. Tin-penetrating hole; 10. Solder hole. Detailed implementation manners

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0041] Embodiment 1

[0042] As Figures 1 to 6 shown, a device for waveguide-to-microstrip transition applicable to high-frequency broadband first adopts a split waveguide to achieve the operability of assembly. A ridge waveguide is constructed through a step structure 3 in the waveguide propagation direction, and a three-stage ridge waveguide is used to achieve waveguide impedance transformation within an ultra-wide frequency band. Then, the step structure 3 is welded to the inner conductor of the glass bead 5, and broadband matching is achieved again by adjusting the distance between the step structure 3 and the outer conductor of the glass bead 2. Finally, the glass bead 5 is spot-welded to the microstrip line 6 through cavity matching 7, ultimately realizing a transition structure of split waveguide - step structure - glass bead - cavity matching - microstrip. The specific solution is as follows:

[0043] (1) Through the combination of the stepped platform structure 3 and the glass bead 5, the present invention achieves triple ultra-wideband matching of this transition structure, enabling the transition structure to possess ultra-wideband characteristics. The first matching is to construct a ridge waveguide through the stepped platform structure 3 in the waveguide propagation direction, and three-stage ridge waveguides are used to achieve waveguide impedance transformation within an ultra-wide frequency band. The second matching is to add an impedance adjustment structure after the three-stage ridge waveguide structure of the stepped platform structure 3, and by adjusting the parameters of this structure and its distance from the outer conductor of the glass bead 5, the second broadband matching is achieved. The third matching is to add a cavity matching section 7 between the glass bead 5 and the microstrip line printed board 6 to match the overall structure to the characteristic impedance of a standard microstrip line, thereby realizing the ultra-wideband characteristics of this transition structure.

[0044] (2) The present invention extracts the traditional waveguide-to-ridge waveguide transition structure as an independent stepped platform structure, which not only ensures the ultra-wideband characteristics of this transition structure but also meets the tolerance requirements of machining accuracy in high-frequency applications, making this transition structure suitable for high-frequency application scenarios. At the same time, in this transition structure, the glass bead 5 is selected to be welded to the stepped platform structure 3. The inner diameter of the glass bead 5 is 0.15 mm and the outer diameter is 1.2 mm. The standard waveguide WR-10 is selected, with a wide-side dimension of 2.54 mm and a narrow-side dimension of 1.27 mm, and the waveguide WR-10 is separated along the wide-side surface, ensuring the operability of welding the stepped platform structure 3 to the whole machine housing 1, the stepped platform structure 3 to the glass bead 5, and the glass bead 5 to the whole machine housing 1.

[0045] (3) The present invention adopts welding holes on the side and top surfaces of the stepped platform structure 3 respectively. The diameter of the side solder hole 10 is 0.25 mm, which is adapted to be welded to the 0.15-mm inner conductor of the glass bead 5. To ensure good welding between the inner conductor of the glass bead 5 and the side welding hole of the stepped platform structure 3, a through-tin groove 9 with a diameter of 0.5 mm and a depth reaching the side welding hole is dug on the top surface of the stepped platform structure 5. The welding quality between the stepped platform structure 3 and the glass bead 5 is ensured through the welding holes on the side and top surfaces of the stepped platform structure 3.

[0046] (4) The present invention adopts the standard waveguide WR-10 (with a wide-side dimension of 2.54 mm and a narrow-side dimension of 1.27 mm), the inner diameter of the glass bead 5 is 0.15 mm, and the outer diameter is 1.2 mm. The outer diameter of the glass bead 5 is smaller than the narrow-side dimension of the waveguide WR-10, realizing the feasibility of the waveguide-glass bead end-feed structure in the W band. At the same time, two solder holes 10 are added along the wide-side direction at the welding position between the glass bead 5 and the overall structure 1, ensuring the solder void rate of the glass bead welding in high-frequency application scenarios.

[0047] The principle of the above scheme is: from the electromagnetic field theory, it can be known that the electromagnetic wave of TE10 mode is transmitted in the waveguide. By adjusting the height of the narrow side of the waveguide, the cutoff wavelength of the waveguide remains unchanged and the characteristic impedance is reduced; using this characteristic, a three-level ridge waveguide structure is adopted to realize impedance transformation in the 78GHz-104GHz frequency band, and then by adding an impedance adjustment structure 8 after the three-level ridge waveguide structure, the TE10 mode of the waveguide is converted into the TEM mode of the coaxial line, thereby realizing the transition from the waveguide to the glass bead; finally, the conversion of the TEM mode to the quasi-TEM mode is completed through the cavity matching section 7. Finally, the present invention realizes a low-cost, easy-to-assemble, airtight and wide-band waveguide to microstrip transition structure suitable for 78GHz-104GHz.

[0048] like Figure 1 As shown, it is a three-dimensional schematic diagram of the back-to-back structure composed of the separated waveguide-step terrace structure-glass bead-cavity matching-microstrip of the present invention, and the back-to-back structure 1 is symmetrical along the center; in the figure, 1 is the overall structure of the back-to-back structure, 2 is the waveguide cover plate, and 3 is the step terrace structure; the step terrace structure 3 is welded on the overall structure 1, and the waveguide cover plate 2 is installed on the overall structure 1 by screws to form a standard waveguide WR-10, and the waveguide wide side size is 2.54mm and the narrow side size is 1.27mm; in the figure, 4 is the upper cover plate of the back-to-back structure, and the upper cover plate 4 is welded to the overall structure 1 by laser sealing.

[0049] The back-to-back structure body 1 comprises a block body 11, a step platform structure mounting groove 12 connected to the center of the top of the block body 11 and extending downward, a glass bead mounting hole 13 located on one side of the step platform structure mounting groove 12, a radio frequency printed circuit board mounting groove 14, and a frame 15 connected to the upper surface of the block body 11 and enclosing the radio frequency printed circuit board mounting groove 14. The number of the step platform structure mounting groove 12 and the glass bead mounting hole 13 are both 2, the glass bead mounting hole 13 is located on both sides of the radio frequency printed circuit board mounting groove 14, the frame 15 is a hollow structure and the middle of both sides extends downward to the block body 11, and the glass bead mounting hole 13 is opened on both sides of the frame 15 and extends in the left and right directions;

[0050] The step-stage structure installation groove 12 is a structure separated along the wide side of the standard waveguide, and the bottom surface of the step-stage structure installation groove 12, the bottom surface of the glass bead installation hole 13 and the bottom surface of the RF printed circuit board installation groove 14 are all at different heights;

[0051] The upper cover plate 4 is welded to the top inner part of the frame 15 by laser.

[0052] like Figure 2As shown in the figure, it is a partial three-dimensional schematic diagram of the back-to-back structure composed of a split waveguide - stepped structure - glass bead - cavity matching - microstrip of the present invention; in the figure, 5 is the glass bead, the outer diameter of the glass bead 5 is 1.2 mm, the outer diameter length is 1 mm, the inner diameter is 0.15 mm, and the inner diameter length is 2.6 mm; in the figure, 6 is the RF printed circuit board, and the RF printed circuit board 6 uses a microwave flexible substrate, with a dielectric constant of 2.2 and a thickness of 0.127 mm; in the figure, the stepped structure 3 and the overall structure 1 form a conversion structure from a standard waveguide WR-10 to a ridge waveguide, and the glass bead 5 is welded to the stepped structure 3 and the RF printed circuit board 6 respectively.

[0053] As Figure 3 shown, it is a cross-sectional view of the back-to-back structure composed of a split waveguide - stepped structure - glass bead - cavity matching - microstrip of the present invention; first, the RF printed circuit board 6 and the glass bead 5 are welded to the overall structure 1, and after welding, a cavity matching 7 is formed; then the stepped structure 3 is welded to the overall structure 1, and at the same time, the side surface of the stepped structure 3 is welded to the inner conductor of the glass bead 5. After welding, an impedance adjustment structure 8 is formed. After installing the waveguide cover plate 2 and the upper cover plate 4, the back-to-back structure composed of a split waveguide - stepped structure - glass bead - cavity matching - microstrip of the present invention is formed.

[0054] As Figure 4 shown, it is a partial three-dimensional schematic diagram of the split waveguide - stepped structure - glass bead - cavity matching - microstrip transition structure of the present invention. There is a solder penetration hole 9 on the top surface of the stepped structure 3. After the inner conductor of the glass bead 5 is inserted into the stepped structure 3, sufficient welding is ensured through the solder penetration hole 9; there are solder holes 10 on the overall structure 1, and the solder holes 10 are distributed on both sides of the glass bead 5 to ensure sufficient welding between the glass bead 5 and the overall structure 1, thereby realizing the airtightness of this transition structure.

[0055] As Figure 5 、 6 shown, it is a simulation diagram of the insertion loss and return loss of the back-to-back structure composed of a split waveguide - stepped structure - glass bead - cavity matching - microstrip of the present invention. In the frequency range of 78 GHz to 104 GHz, the insertion loss of this structure is not greater than 0.1 dB, and the return loss is not greater than -20 dB, having good RF transmission performance.

[0056] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A device for waveguide-to-microstrip transition applicable to high-frequency broadband, characterized in that: It includes a back-to-back structure body (1), waveguide cover plates (2) connected to the upper parts of both ends of the back-to-back structure body (1), stepped platform structures (3) connected to both ends of the top of the back-to-back structure body (1), an upper cover plate (4) located between the waveguide cover plates (2) and hermetically connected to the top of the back-to-back structure body (1), a glass bead (5), a radio frequency printed circuit board (6) sequentially connected to the stepped platform structure (3), a cavity matching (7) located between the glass bead (5) and the radio frequency printed circuit board (6), and an impedance adjustment structure (8) connected between the top of the stepped platform structure (3) and the glass bead (5). The numbers of the waveguide cover plates (2), the stepped platform structures (3), the glass beads (5), the cavity matching (7), and the impedance adjustment structure (8) are all 2; The stepped platform structure (3) is a ridge waveguide, which forms a conversion structure from a standard waveguide to a ridge waveguide with the back-to-back structure body (1) for the first impedance transformation; after the stepped platform structure (3) is welded to the glass bead (5), it forms the impedance adjustment structure (8) for the second broadband matching; the cavity matching (7) is the third matching, which matches the device of waveguide-to-microstrip transition to the characteristic impedance of a standard microstrip line.

2. The device for waveguide-to-microstrip transition applicable to high-frequency broadband according to claim 1, characterized in that: The stepped platform structure (3) is a three-stage ridge waveguide structure for impedance transformation in the frequency band of 78 GHz - 104 GHz. The impedance adjustment structure (8) converts the TE10 mode of the waveguide into the TEM mode of the coaxial line for the transition from the waveguide to the glass bead; finally, the conversion from the TEM mode to the quasi-TEM mode is completed through the cavity matching (7).

3. A device for waveguide-to-microstrip transition applicable to high-frequency broadband, characterized in that: The back-to-back structure body (1) is an integrally formed structure symmetric about the center; The back-to-back structure body (1) includes a block-shaped body (11), stepped platform structure mounting grooves (12) connected to both ends of the center of the top of the block-shaped body (11) and extending downward, a glass bead mounting hole (13), a radio frequency printed circuit board mounting groove (14) sequentially located on one side of the stepped platform structure mounting groove (12), and a frame (15) connected to the upper surface of the block-shaped body (11) and surrounding the radio frequency printed circuit board mounting groove (14) inside. The numbers of the stepped platform structure mounting grooves (12) and the glass bead mounting holes (13) are both 2. The glass bead mounting holes (13) are located on both sides of the radio frequency printed circuit board mounting groove (14). The frame (15) is a hollow structure and the middle parts of both sides extend downward to the block-shaped body (11). The glass bead mounting holes (13) are opened on both sides of the frame (15) and extend in the left and right directions; The stepped platform structure mounting groove (12) is a structure separated along the wide side of the standard waveguide. The bottom surfaces of the stepped platform structure mounting groove (12), the glass bead mounting hole (13), and the radio frequency printed circuit board mounting groove (14) have different heights; The upper cover plate (4) is laser welded to the inside of the top of the frame (15).

4. A device for waveguide-to-microstrip transition applicable to high-frequency broadband, characterized in that: The stepped platform structure (3) includes a stepped structure and a base connected to the bottom of the stepped structure. A base mounting groove for connecting to the base is provided at the bottom of the stepped platform structure mounting groove (12).

5. The device for waveguide-to-microstrip transition applicable to high-frequency broadband according to claim 1, characterized in that: The impedance adjustment structure (8) is the fourth layer of steps connected to the top of the stepped platform structure (3). A bead outer conductor mounting groove extending in the left - right direction is provided inside the fourth layer of steps; The second - stage broadband matching is performed by adjusting the distance between the outer conductor of the bead (5) and the impedance adjustment structure (8) and the structural parameters of the impedance adjustment structure (8).

6. A device for waveguide-to-microstrip transition applicable to high-frequency broadband, characterized in that: The outer diameter of the bead (5) is smaller than the narrow - side dimension of the standard waveguide to obtain a waveguide - bead end - fed structure in the W - band.

7. A device for waveguide-to-microstrip transition applicable to high-frequency broadband, characterized in that: The top of the stepped platform structure (3) is connected to a tinned hole (9). After the inner conductor of the bead (5) is inserted into the stepped platform structure (3), it is welded through the tinned hole (9). Solder holes (10) are connected to both the left and right sides of the bead mounting hole of the back - to - back structure body (1); The device for waveguide - to - microstrip transition is a centrally symmetric structure. The waveguide cover plate (2) is installed on the back - to - back structure body (1) by screws.

8. A device for waveguide-to-microstrip transition applicable to high-frequency broadband, characterized in that: The standard waveguide is a standard waveguide WR - 10 with a wide - side dimension of 2.54 mm and a narrow - side dimension of 1.27 mm; The outer conductor of the bead (5) has a diameter of 1.2 mm and a length of 1 mm, and the inner conductor has a diameter of 0.15 mm and a length of 2.6 mm; The radio - frequency printed circuit board (6) is a microwave flexible substrate with a dielectric constant of 2.2 and a thickness of 0.127 mm.

9. A device for waveguide-to-microstrip transition applicable to high-frequency broadband, according to any one of claims 1 to 8, characterized in that: The preparation method of the device for waveguide - to - microstrip transition includes the following steps: S1. Weld the side of the stepped platform structure (3) to the inner conductor of the bead (5). After welding, the impedance adjustment structure (8) is formed, and then the stepped platform structure (3) is welded to the back - to - back structure body (1); S2. Weld the radio - frequency printed circuit board (6) and the bead (5) to the back - to - back structure body (1). After welding, the cavity matching (7) is formed; S3. After installing the waveguide cover plate (2) and the upper cover plate (4), a back - to - back structure composed of a split - type waveguide - stepped platform structure - bead - cavity matching - microstrip is obtained, and a device for waveguide - to - microstrip transition applicable to high - frequency broadband is prepared.

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