A low reflection adapter

Abstract

The application discloses a low-reflection adapter, which comprises an input transmission line and an output transmission line. A plurality of metal units and at least one raised metal block are arranged in the output transmission line. The height of the raised metal block is greater than the height of the metal unit on the side close to the input transmission line. By using asymmetric metal units with width and height mutation and a whole metal waveguide, the application can realize a lower port reflection coefficient than the prior art under the premise of ensuring wideband or even super wideband. The application can be applied to the fields of microwave communication and microwave energy.

Description

Technical Field

[0001] This invention relates to the field of adapters, and more specifically to a low-reflection adapter. Background Technology

[0002] In microwave technology, the transition between the same modes in transmission lines of the same type but different sizes, between different modes in the same transmission line, and between different modes in different transmission lines are classic research topics. Coaxial-waveguide transitions, coaxial-ridge waveguide transitions, microstrip-waveguide transitions, and waveguide-ridge waveguide transitions are typical examples.

[0003] In these adapters, achieving the lowest possible port reflection coefficient, the lowest possible insertion loss, the widest possible bandwidth, and the highest possible power capacity are important design considerations.

[0004] For example, the most common coaxial-rectangular waveguide adapter utilizes a coaxial transmission line located at the center of the wide side, and several metal ridges located on the center line of the bottom surface of the rectangular waveguide. The height of all the metal ridges decreases monotonically along the rectangular waveguide. The signal conductor of the coaxial transmission line is connected to the first metal ridge, and the entire structure is symmetrical with respect to the axis of the rectangular waveguide. This achieves a high-power, full-bandwidth coaxial waveguide adapter, which can obtain a reflection coefficient as low as -20dB across the full bandwidth of a standard waveguide. However, it is difficult to further reduce the reflection coefficient with this type of adapter. Summary of the Invention

[0005] The purpose of this invention is to provide a low-reflection adapter to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following solution:

[0007] A low-reflection adapter includes an input transmission line and an output transmission line with its wide side along the X direction, its high side along the Y direction, and its axis along the Z direction. The input transmission line is a two-conductor or multi-conductor transmission line, including at least one signal conductor and at least one ground conductor. The output terminal is located at the top of the output transmission line along the Z direction. N metal units, where N is greater than or equal to 2, are disposed within the output transmission line and connected to the inner wall of the output transmission line at its bottom along the -Y direction. Any one of the metal units is labeled as the nth metal unit, and n increases sequentially along the Z direction; n can be 1, 2, ..., N. All the metal units are sequentially connected along the Z direction. The height of all the metal units along the Y direction decreases monotonically sequentially along the Z direction. At least one signal conductor of the input transmission line is inserted into the output transmission line and connected to one of the metal units. The X, Y, and Z directions form a Cartesian coordinate system. The adapter is characterized by further including at least one raised metal block.

[0008] The number of raised metal blocks can be 1. The bottom of each raised metal block is connected to the bottom inner wall of the output transmission line. Each raised metal block is connected to the m-th metal unit in the -Z direction. The height of each raised metal block is greater than the height of the m-th metal unit. Here, m can be 1, 2, ..., N.

[0009] The number of raised metal blocks can be greater than 1. The bottom of each raised metal block is connected to the bottom inner wall of the output transmission line. Any one of the raised metal blocks is connected to the m-th metal unit in the -Z direction. The height of each raised metal block is greater than the height of the m-th metal unit. Here, m can be 2, ..., or N.

[0010] The axis of the input transmission line can be along the Z direction, and the low-reflection adapter is a direct-feed adapter.

[0011] The axis of the input transmission line can also be along the Y direction, and the low-reflection adapter is an offset feed adapter.

[0012] To further reduce the reflection coefficient of the low-reflection adapter within the operating bandwidth, the angle between the projection of the line connecting at least two adjacent metal units or the centroid of the adjacent metal unit and the raised metal block in the XZ plane perpendicular to the Y direction and the Z direction is greater than 5 degrees.

[0013] To further reduce the reflection coefficient of the low-reflection adapter within its operating bandwidth, at least two of the metal units have different widths along the X direction.

[0014] In a preferred design, the input transmission line is a coaxial line. The input transmission line may also be a microstrip line, a stripline, or a coplanar waveguide.

[0015] To reduce manufacturing costs, the output transmission line is a single, continuous metal tube. In this case, all metal units and the raised metal blocks can be machined as a single piece of metal into a single assembly using milling or other machining methods. This metal assembly can be fixed to the bottom of the output transmission line using screws or welding. The term "continuous metal tube" specifically refers to a metal tube whose cross-sectional shape remains unchanged along its axis, meaning it is machined as a single unit, not pre-machined into several sections and then joined together.

[0016] If the input transmission line is a coaxial line, the output transmission line can be a rectangular waveguide, and the low-reflection adapter is a coaxial-rectangular waveguide adapter. Alternatively, the output transmission line can be a circular waveguide, and the low-reflection adapter is a coaxial-circular waveguide adapter.

[0017] Of course, the output transmission line can also be other transmission lines, such as square waveguides, ridge waveguides, double ridge waveguides, etc.

[0018] The design principle of this invention is as follows: Traditional coaxial-to-rectangular waveguide or coaxial-to-ridge waveguide adapters use multiple sequentially connected matching transmission lines to achieve matching transitions from the coaxial transmission line to the waveguide or from the coaxial transmission line to the ridge waveguide. Each matching transmission line consists of a rectangular waveguide section and a metal unit at its bottom. To achieve good matching within a certain bandwidth, the waveguides of adjacent matching transmission lines have the same cross-sectional dimensions, and the height of the metal units decreases monotonically from one end of the coaxial transmission line to the other end of the adapter, while the width of the metal units is the same, and the metal units are arranged on a symmetrical axis. Thus, viewed from one end of the coaxial transmission line, the phase of the reflection coefficient caused by the discontinuity between any adjacent matching transmission lines is the same, either 0 degrees or 180 degrees. The reflection coefficients differ only in magnitude. The same phase of the reflection coefficients between different matching transmission lines is the core reason why it is difficult to further reduce the reflection coefficient. To achieve a lower reflection coefficient, such as at full bandwidth or 41% relative bandwidth, this invention uses one or more anti-phase matched reflection transmission lines as matching transmission lines. This anti-phase matched transmission line enables phase reversal of the reflection coefficients caused by discontinuities between adjacent matching transmission lines, i.e., a 180-degree phase difference. The anti-phase matched transmission line may include a raised metal block between adjacent height-decreasing metal units. The anti-phase matched transmission line may also include a metal unit laterally misaligned in the wide-side direction. Furthermore, the anti-phase matched transmission line may include a metal unit with a sudden width change.

[0019] The centroid here is defined as the center of gravity of the shape after it is uniformly filled with a certain substance.

[0020] Width: The dimension of any structure along the X direction.

[0021] Height: The dimension of any structure along the Y direction.

[0022] Metal elements misaligned in the wide side direction: The metal elements are configured as a non-mirror symmetric structure relative to the YZ plane.

[0023] The beneficial effects of this invention are as follows: This invention provides a low-reflection adapter. By employing asymmetrical metal units, metal units of different widths, and raised metal blocks with abrupt height changes to construct an anti-phase matching transmission line, a lower port reflection coefficient than existing technologies can be achieved while ensuring broadband or even ultra-broadband connectivity. Attached Figure Description

[0024] Figure 1 Top view of common technologies

[0025] Figure 2 AA-direction cross-sectional view of common technologies

[0026] Figure 3 Top view of the present invention and embodiment 1

[0027] Figure 4 for Figure 3 AA direction section view

[0028] Figure 5 Top view for implementing Example 2

[0029] Figure 6 for Figure 5 AA direction section view

[0030] Figure 7 To implement the model of Example 3.

[0031] Figure 8 The reflection coefficient for Example 3.

[0032] Figure 9 To implement the model of Example 4.

[0033] Figure 10 The reflection coefficient for Example 4.

[0034] The labels in the diagram represent:

[0035] 1-Input transmission line, 2-Output terminal, 3-Output transmission line, 4-Metal unit, 5-Raised metal block. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0037] like Figure 1 and Figure 2 As shown, this is a common coaxial rectangular waveguide adapter using existing conventional technology. The adapter includes an input transmission line 1 and an output transmission line 3 with its wide side along the X direction, its high side along the Y direction, and its axis along the Z direction. The input transmission line 1 is a two-conductor transmission line, including a signal conductor and a ground conductor. The output terminal 2 is located at the top of the output transmission line 3 along the Z direction. Four metal units 4 are disposed within the output transmission line 3, connected to the inner wall of the output transmission line 3 at its bottom along the -Y direction. Any one of these metal units 4 is designated as the nth metal unit 4, where n increases sequentially along the Z direction; n can be 1, 2, 3, or 4. All the metal units 4 are sequentially connected along the Z direction. The height of all the metal units 4 decreases monotonically along the Z direction. A signal conductor from the input transmission line 1 is inserted into the output transmission line 3 and connected to the first metal unit 4 therein.

[0038] All the metal units 4 have the same width.

[0039] The metal units 4 are all distributed in a mirror-symmetric manner with the YZ plane as the plane of symmetry.

[0040] The input transmission line 1 is a coaxial line. The output transmission line 3 is a rectangular waveguide.

[0041] Implementation Example 1

[0042] like Figure 3 and Figure 4 As shown.

[0043] A low-reflection adapter includes an input transmission line 1 and an output transmission line 3 with its wide side along the X direction, its narrow side along the Y direction, and its axis along the Z direction. The input transmission line 1 is a two-conductor transmission line, including a signal conductor and a ground conductor. An output terminal 2 is located at the top of the output transmission line 3 along the Z direction. Three metal units 4 are disposed within the output transmission line 3, connected to the inner wall of the output transmission line 3 at its bottom along the -Y direction. Any one of the metal units 4 is designated as the nth metal unit 4, where n increases sequentially along the Z direction; n can be 1, 2, or 3. All the metal units 4 are sequentially connected along the Z direction. The height of all the metal units 4 decreases monotonically along the Z direction. A signal conductor from the input transmission line 1 is inserted into the output transmission line 3 and connected to the first metal unit 4 therein. A lifting metal block 5 is also provided.

[0044] The number of raised metal blocks 5 is one. The bottom of the raised metal block 5 is connected to the bottom inner wall of the output transmission line 3. The raised metal block 5 is connected to the third metal unit 4 in the -Z direction. The height of the raised metal block 5 is greater than the height of the third metal unit 4.

[0045] The axis of the input transmission line 1 is along the Y direction, and the low-reflection adapter is an offset feed adapter.

[0046] The angle between the projection of the line connecting the centroids of two adjacent second and third metal units 4 in the XZ plane perpendicular to the Y direction and the Z direction is greater than 5 degrees.

[0047] The widths of the second and third metal units 4 along the X direction are different.

[0048] The width of the second metal unit 4 along the X direction is greater than or less than the width of the third metal unit 4 along the X direction.

[0049] The input transmission line 1 is a coaxial line.

[0050] The output transmission line 3 is a single, continuous metal tube. All the metal units 4 and the raised metal block 5 are formed as a single piece of metal through milling. This metal assembly is fixed to the bottom of the output transmission line 3 using screws or welding.

[0051] The output transmission line 3 is a rectangular waveguide, and the low-reflection adapter is a coaxial-rectangular waveguide adapter.

[0052] Implementation Example 2

[0053] like Figure 5 and 6 As shown.

[0054] The only difference from Implementation Example 1 is that the axis of the input transmission line 1 is along the Z direction, and the low-reflection adapter is a direct-feed adapter.

[0055] Implementation Example 3

[0056] like Figure 7 As shown.

[0057] This implementation example is a specific implementation of Implementation Example 1, and is an offset feed adapter. Figure 7 It is a three-dimensional model. Figure 8 This is the calculated curve of the reflection coefficient at the input end of input transmission line 1 as a function of frequency. From... Figure 8 As can be seen, within the full operating bandwidth of the BJ26 standard waveguide from 2.17 to 3.3 GHz, the reflection coefficient is below -27 dB, corresponding to a VSWR below 1.1. Compared to the common adapter's reflection coefficient of -20 dB, the reflection coefficient of this invention is reduced by more than four times. A lower reflection coefficient means lower insertion loss and less interference to nearby devices. The advantages of this adapter over conventional technology are obvious.

[0058] Implementation Example 4

[0059] like Figure 9 As shown.

[0060] This implementation example is a specific implementation of Implementation Example 2, and is a direct feeder adapter. Figure 9 It is a three-dimensional model. Figure 10 This is the calculated curve of the reflection coefficient at the input end of input transmission line 1 as a function of frequency. From... Figure 10 As can be seen, within the full operating bandwidth of the BJ26 standard waveguide from 2.17 to 3.3 GHz, the reflection coefficient is below -29 dB, corresponding to a standing wave ratio (VSWR) below 1.1. Compared to the common adapter's reflection coefficient of -20 dB, the reflection coefficient of this invention is reduced by more than eight times.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. The main innovation of the present invention lies in the use of asymmetrical metal units with non-monotonic width and height variations, employing a single metal tube to achieve a low-cost, low-reflection adapter. In actual manufacturing, some right angles require rounding for milling the adapter. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A low-reflection adapter, comprising an input transmission line (1) and an output transmission line (3) with its axis along the Z direction; the input transmission line (1) is a two-conductor or multi-conductor transmission line, comprising at least one signal conductor and at least one ground conductor; an output end (2) is disposed at the top end of the output transmission line (3) along the Z direction; N metal units (4) are disposed in the output transmission line (3) and connected to the inner wall of the output transmission line (3) at the bottom along the -Y direction, wherein N is greater than or equal to 2; any one of the metal units (4) is referred to as the nth metal unit (4), and n increases sequentially along the Z direction; all the metal units (4) are sequentially connected along the Z direction; the height of all the metal units (4) along the Z direction decreases monotonically along the Y direction; at least one signal conductor of the input transmission line (1) is inserted into the output transmission line (3) and connected to one of the metal units (4); further comprising the X direction, characterized in that, It is also provided with at least one raised metal block (5); the angle between the projection of the line connecting the centroid of at least two adjacent metal units (4) or one adjacent metal unit (4) and one raised metal block (5) in the XZ plane and the Z direction is greater than 5 degrees.

2. A low-reflection adapter according to claim 1, characterized in that, The number of the raised metal blocks (5) is 1; the bottom of the raised metal block (5) is connected to the bottom inner wall of the output transmission line (3); the raised metal block (5) is connected to the m-th metal unit (4) in the -Z direction; the height of the raised metal block (5) is greater than the height of the m-th metal unit (4).

3. A low-reflection adapter according to claim 1, characterized in that, The number of the raised metal blocks (5) is greater than 1; the bottom of the raised metal blocks (5) is connected to the bottom inner wall of the output transmission line (3); any one of the raised metal blocks (5) is connected to the m-th metal unit (4) in the -Z direction; the height of the raised metal blocks (5) is greater than the height of the m-th metal unit (4).

4. A low-reflection adapter according to claim 1, characterized in that, The axis of the input transmission line (1) is along the Z direction.

5. A low-reflection adapter according to claim 1, characterized in that, The axis of the input transmission line (1) is along the Y direction.

6. A low-reflection adapter according to claim 1, characterized in that, At least two of the metal units (4) have different widths along the X direction.

7. A low-reflection adapter according to claim 1, characterized in that, The input transmission line (1) is a coaxial line, a microstrip line, a strip line, or a coplanar waveguide.

8. A low-reflection adapter according to any one of claims 1 to 7, characterized in that, The output transmission line (3) is a complete metal tube; the output transmission line (3) is a rectangular waveguide.

9. A low-reflection adapter according to any one of claims 1 to 7, characterized in that, The output transmission line (3) is a complete metal tube; the output transmission line (3) is a circular waveguide, or a square waveguide, or a single-ridge waveguide, or a double-ridge waveguide, or a ridge gap waveguide.

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