A substrate integrated coaxial line-ridge waveguide broadband transition structure

Abstract

The present invention discloses a substrate integrated coaxial line-ridge waveguide broadband transition structure. The transition structure includes an output ridge waveguide located in the upper part, a substrate integrated coaxial line part located in the middle, and a ridge waveguide metal back cavity located in the lower part. Among them, metal ridges are provided on both sides of the output ridge waveguide. A coupling window is provided in the middle of the first metal layer of the substrate integrated coaxial line part. Metal hole array impedance matching structures are provided at both ends in the coupling window, and metal shielding holes are provided around the coupling window. The second metal layer includes an input substrate integrated coaxial line, a substrate integrated coaxial line impedance matching structure, and a guided electromagnetic wave mode conversion structure connected in sequence. The structure of the third metal layer is the same as that of the first metal layer. The present invention adopts the form of a tapered transmission line to convert the TEM mode guided electromagnetic wave into a TE 10 mode guided electromagnetic wave, with a compact structure, and performance such as in-band return loss and insertion loss can meet the requirements of engineering applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic device manufacturing, and particularly relates to a substrate integrated coaxial line-ridge waveguide broadband transition structure. Background Art

[0002] In recent years, with the rapid development of millimeter-wave technology, millimeter-wave devices have made great progress, and the demand for millimeter-wave integrated systems is increasing day by day. In traditional microwave circuits, microstrip lines are often used to connect circuits. However, in the millimeter-wave band, as the frequency increases, microstrip lines gradually cannot meet the requirements of low transmission loss of integrated circuits. Along with this, there is also an increase in energy leakage and a decrease in anti-interference ability. Compared with microstrip lines, substrate integrated coaxial lines have lower losses, stronger anti-interference ability, and lower processing difficulty, and are thus increasingly widely used in millimeter-wave integrated systems.

[0003] In order to realize the feeding or testing of millimeter-wave communication systems, it is often necessary to transition the input or output structure of millimeter-wave circuits into a waveguide structure to reduce insertion loss and improve efficiency. In addition to common rectangular waveguides, ridge waveguides have received more and more attention due to their advantages such as small size, high power capacity, wide working bandwidth, and easy processing.

[0004] Currently, some microstrip line to rectangular waveguide transition structures have been proposed. Most of these structures have mediocre performance, or are complex in structure and difficult to process. There are few reports on substrate integrated coaxial line to ridge waveguide transition structures. Considering the excellent characteristics of substrate integrated coaxial lines and ridge waveguides, designing a transition structure that meets engineering requirements and combines the two can achieve the best results. Summary of the Invention

[0005] Technical Problem: The purpose of the present invention is to provide a substrate integrated coaxial line-ridge waveguide broadband transition structure to meet engineering needs.

[0006] Technical Solution: To achieve the above object, a substrate integrated coaxial line-ridge waveguide broadband transition structure of the present invention includes an output ridge waveguide located in the upper part, a substrate integrated coaxial line part located in the middle, and a ridge waveguide metal back cavity located in the lower part. Among them, metal ridges are provided on both sides of the output ridge waveguide. The substrate integrated coaxial line part includes two dielectric plates, a first metal layer located on the top layer of the two dielectric plates, a second metal layer located between the two dielectric plates, and a third metal layer located on the bottom layer of the two dielectric plates. A coupling window is provided in the middle of the first metal layer. Metal hole array impedance matching structures are provided at both ends within the coupling window, and metal shielding holes are provided around the coupling window. The second metal layer includes an input substrate integrated coaxial line, a substrate integrated coaxial line impedance matching structure, and a guided electromagnetic wave mode conversion structure connected in sequence. The structure of the third metal layer is the same as that of the first metal layer.

[0007] The first metal layer on the top layer and the third metal layer on the bottom layer of the substrate integrated coaxial line part form a metal ground, and the first metal layer and the third metal layer are connected by metal shielding holes.

[0008] The characteristic impedance of the input substrate integrated coaxial line is 50Ω.

[0009] The impedance matching structure of the substrate integrated coaxial line includes a connected quarter-wavelength impedance transformer and a section of inductive transmission line.

[0010] The guided electromagnetic wave mode conversion structure is a T-shaped metal patch, and the center of the structure coincides with the centers of the ridge waveguide metal back cavity and the output ridge waveguide.

[0011] Coupling windows with the same shape as the inner walls of the ridge waveguide metal back cavity and the output ridge waveguide are etched on the metal ground on both sides of the guided electromagnetic wave mode conversion structure, and metal shielding holes are arranged around the coupling windows.

[0012] The metal hole array impedance matching structure includes a square metal patch, and a symmetric 2×2 metal through-hole array is provided in the square metal patch.

[0013] Both dielectric plates use Taconic TLY-5 dielectric substrates with a thickness of 0.254mm.

[0014] The ridge waveguide metal back cavity, the substrate integrated coaxial line part, and the output ridge waveguide are connected together by bolts.

[0015] Beneficial effects: The advantages of the substrate integrated coaxial line-ridge waveguide broadband transition structure provided by the present invention are as follows: (1) By setting an input substrate integrated coaxial line, a multi-section substrate integrated coaxial line impedance matching structure, a T-shaped guided electromagnetic wave mode conversion structure, a ridge waveguide metal back cavity, and an output ridge waveguide connected in sequence, the conversion of TEM-mode guided electromagnetic waves to TE 10 mode guided electromagnetic waves is realized; (2) Low return loss and insertion loss in a wide band are achieved.

[0016] In order to more clearly illustrate the technical solutions in the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. Description of the Drawings

[0017] Figure 1 It is an exploded view schematic diagram of a substrate integrated coaxial line-ridge waveguide broadband transition structure provided by the present invention;

[0018] Figure 2 It is a top view of a substrate integrated coaxial line-ridge waveguide broadband transition structure provided by the present invention;

[0019] Figure 3It is a schematic cross-sectional structure diagram of an output ridge waveguide and a ridge waveguide metal back cavity;

[0020] Figure 4 It is a schematic longitudinal centerline sectional structure diagram of a ridge waveguide metal back cavity of a substrate integrated coaxial line-ridge waveguide broadband transition structure provided by the present invention;

[0021] Figure 5 It is a schematic diagram of a dielectric layer stacking structure of a substrate integrated coaxial line-ridge waveguide broadband transition structure provided by the present invention;

[0022] Figure 6 It is Figure 5 a schematic structure diagram of the first metal layer M1 in

[0023] Figure 7 It is Figure 5 a schematic structure diagram of the second metal layer M2 in

[0024] Figure 8 It is Figure 5 a schematic structure diagram of the third metal layer M3 in

[0025] Figure 9 It is a schematic diagram of an echo loss simulation curve of a substrate integrated coaxial line-ridge waveguide broadband transition structure provided by the present invention;

[0026] Figure 10 It is a schematic diagram of an echo loss simulation curve of a substrate integrated coaxial line-ridge waveguide broadband transition structure after removing the metal hole array impedance matching structure provided by the present invention;

[0027] Figure 11 It is a schematic diagram of an insertion loss simulation curve of a substrate integrated coaxial line-ridge waveguide broadband transition structure provided by the present invention;

[0028] In the figure, there are: an input substrate integrated coaxial line 1, a substrate integrated coaxial line impedance matching structure 2, a guided electromagnetic wave mode conversion structure 3, a metal hole array impedance matching structure 4, a metal shielding hole 5, a ridge waveguide metal back cavity 6, an output ridge waveguide 7, a dielectric plate 8, a metal ground 9, a metal ridge 10, a quarter-wavelength impedance transformer 11, an inductive transmission line 12, a coupling window 13, a metal through-hole array 14, a square metal patch 15, a first metal layer M1, a second metal layer M2, and a third metal layer M3. Detailed implementation manners

[0029] The technical solutions and beneficial effects of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] Please refer to Figures 1 to 8, The present invention provides a substrate integrated coaxial line - ridge waveguide broadband transition structure. The transition structure includes an output ridge waveguide 7 located at the upper part, a substrate integrated coaxial line part located in the middle, and a ridge waveguide metal back cavity 6 located at the lower part. Among them, metal ridges 10 are provided on both sides of the output ridge waveguide 7. The substrate integrated coaxial line part includes two dielectric plates 8, a first metal layer M1 located on the top layer of the two dielectric plates 8, a second metal layer M2 located between the two dielectric plates 8, and a third metal layer M3 located on the bottom layer of the two dielectric plates 8. A coupling window 13 is provided in the middle of the first metal layer M1. Metal hole array impedance matching structures 4 are provided at both ends within the coupling window 13, and metal shielding holes 5 are provided around the coupling window 13. The second metal layer M2 includes an input substrate integrated coaxial line 1, a substrate integrated coaxial line impedance matching structure 2, and a guided electromagnetic wave mode conversion structure 3 connected in sequence. The structure of the third metal layer M3 is the same as that of the first metal layer M1.

[0031] As a specific example, as Figure 1 shown, the ridge waveguide metal back cavity 6, the output ridge waveguide 7, and the dielectric plate 8 are connected together by bolts.

[0032] As a specific example, as Figure 3 and Figure 4 shown, the transverse dimensions of the ridge waveguide metal back cavity 6 and the output ridge waveguide 7 are 5mm×2mm, the transverse dimensions of the metal ridges 10 on both sides are 1.8mm×0.55mm, and the depth of the ridge waveguide metal back cavity 6 is 1.3mm.

[0033] As a specific example, as Figure 5 shown, the dielectric plate 8 includes two dielectric substrates of Taconic TLY - 5 with a thickness of 0.254mm, and the first metal layer M1, the second metal layer M2, and the third metal layer M3.

[0034] As a specific example, as Figure 7 shown, the characteristic impedance of the input substrate integrated coaxial line 1 is 50Ω, the width is 0.4mm, and the length is 1.2mm.

[0035] As a specific example, as Figure 7 shown, the substrate integrated coaxial line impedance matching structure 2 is located in the second metal layer M2 and includes a quarter - wavelength impedance transformer 11 and a section of inductive transmission line 12. The length of the quarter - wavelength impedance transformer 11 is 1.5mm and the width is 0.67mm; the length of the inductive transmission line 12 is 0.8mm and the width is 0.85mm.

[0036] As a specific example, as Figure 7As shown, the guiding electromagnetic wave mode conversion structure 3 is a T-shaped metal patch located in the second metal layer M2. The longitudinal part has a line width of 0.44 mm and a length of 0.71 mm. The transverse part has a width of 1.14 mm and a length of 0.6 mm. The center coincides with the centers of the ridge waveguide metal back cavity 6 and the output ridge waveguide 7.

[0037] As a specific example, as Figure 6 and Figure 8 shown, coupling windows 13 with the same size are etched at the positions where the first metal layer M1 and the third metal layer M3 are connected to the ridge waveguide metal back cavity 6 and the output ridge waveguide 7.

[0038] As a specific example, as Figure 6 and Figure 8 shown, the metal hole array impedance matching structure 4 includes two groups of 2×2 metal through-hole arrays 14 symmetric about the guiding electromagnetic wave mode conversion structure 3 and a total of four square metal patches 15 located in the first metal layer M1 and the third metal layer M3. The diameter of the metal through-holes in the metal through-hole array 14 is 0.3 mm, and the pitch is 0.55 mm. The size of the square patch is 0.93 mm * 0.93 mm.

[0039] As a specific example, as Figures 6 to 8 shown, the diameter of the metal shielding holes 5 is 0.3 mm, and the pitch is 0.5 mm.

[0040] In order to verify the authenticity and reliability of the substrate integrated coaxial line-ridge waveguide broadband transition structure provided by the present invention, an example was specifically designed for verification. Figures 9 to 11 The relevant performance simulation parameters for the design example are as follows. It can be seen from the simulation results that in the frequency band of 22.40 GHz - 48.65 GHz, the transition structure has good matching characteristics and low insertion loss characteristics. Especially after introducing the metal hole array impedance matching structure 4, the matching performance of the transition structure in the range of 43.85 GHz - 48.65 GHz has been further improved.

[0041] The present invention is described by taking 20 GHz - 50 GHz as an example, and this structure can be extended for use in the range of 20 GHz - 110 GHz.

[0042] The above are only the preferred embodiments of the present invention, which are used to illustrate the technical idea of the present invention. The protection scope of the present invention cannot be limited thereby. Any modification made without departing from the principle of the present invention falls within the protection scope of the present invention.

Claims

1. A substrate integrated coaxial line - ridge waveguide broadband transition structure, characterized in that, the transition structure includes an output ridge waveguide (7) located at the upper part, a substrate integrated coaxial line part located in the middle, and a ridge waveguide metal back cavity (6) located at the lower part; wherein, metal ridges (10) are provided on both sides of the output ridge waveguide (7), and the substrate integrated coaxial line part includes two dielectric plates (8), a first metal layer (M1) on the top layer of the two dielectric plates (8), a second metal layer (M2) between the two dielectric plates (8), and a third metal layer (M3) on the bottom layer of the two dielectric plates (8); a coupling window (13) is provided in the middle of the first metal layer (M1), metal hole array impedance matching structures (4) are provided at both ends in the coupling window (13), and metal shielding holes (5) are provided around the coupling window (13); the second metal layer (M2) includes a sequentially connected input substrate integrated coaxial line (1), a substrate integrated coaxial line impedance matching structure (2), and a guided electromagnetic wave mode conversion structure (3); the structure of the third metal layer (M3) is the same as that of the first metal layer (M1); the metal hole array impedance matching structure (4) includes square metal patches (15), and a symmetric 2×2 metal through - hole array (14) is provided in the square metal patches (15).

2. The substrate integrated coaxial line - ridge waveguide broadband transition structure according to claim 1, characterized in that, the first metal layer (M1) and the third metal layer (M3) on the top layer and the bottom layer of the substrate integrated coaxial line part form a metal ground (9), and the first metal layer (M1) and the third metal layer (M3) are connected by metal shielding holes (5).

3. The substrate integrated coaxial line - ridge waveguide broadband transition structure according to claim 1, characterized in that, the characteristic impedance of the input substrate integrated coaxial line (1) is 50Ω.

4. The substrate integrated coaxial line - ridge waveguide broadband transition structure according to claim 1, characterized in that, the substrate integrated coaxial line impedance matching structure (2) includes a connected quarter - wavelength impedance transformer (11) and a section of inductive transmission line (12).

5. The substrate integrated coaxial line - ridge waveguide broadband transition structure according to claim 1, characterized in that, the guided electromagnetic wave mode conversion structure (3) is a T - shaped metal patch, and the center of the structure coincides with the centers of the ridge waveguide metal back cavity (6) and the output ridge waveguide (7).

6. The substrate integrated coaxial line - ridge waveguide broadband transition structure according to claim 1, characterized in that, coupling windows (13) with the same shape as the inner walls of the ridge waveguide metal back cavity (6) and the output ridge waveguide (7) are etched on the metal ground (9) on both the upper and lower sides of the guided electromagnetic wave mode conversion structure (3), and metal shielding holes (5) are provided around the coupling windows (13).

7. The substrate integrated coaxial line - ridge waveguide broadband transition structure according to claim 1, characterized in that, both of the two dielectric plates (8) are made of Taconic TLY - 5 dielectric substrates with a thickness of 0.254mm.

8. The substrate integrated coaxial line-ridge waveguide broadband transition structure according to claim 1, characterized in that, the ridge waveguide metal back cavity (6), the substrate integrated coaxial line part, and the output ridge waveguide (7) are connected together by bolts.

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