A high isolation waveguide coupler

Abstract

The present invention discloses a high-isolation waveguide coupler, including a main waveguide, a coupling branch waveguide, a coupling probe and a power divider; the main waveguide and the coupling branch waveguide are perpendicular to each other and isolated, and are connected through at least one cross coupling hole, and the cross coupling hole is arranged on the diagonal of the overlap area of ​​the wide sides of the main waveguide and the coupling branch waveguide; the wide side opening of the coupling branch waveguide, the coupling probe passes through the wide side opening perpendicular to the plane where the wide side of the coupling branch waveguide is located, and the power divider is connected to the coupling branch waveguide through the coupling probe. The main waveguide and the coupling branch waveguide are coupled by a cross-coupling hole, and the cross coupling hole can meet the needs of large coupling amount and high isolation. And the coupling end empty waveguide is connected to the multi-way power divider through the coupling probe, so that the standing wave ratio of the output coupling port of the multi-way power divider is small, and the overall size of the entire coupler is small, which is suitable for occasions with high requirements on the size and performance of the coupler.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic wave components, and in particular to a high-isolation waveguide coupler. Background Art

[0002] Waveguide synthesis is a power synthesis method widely used in microwave systems. Its function is to synthesize multiple power channels to obtain greater power. The performance of the synthesis network, such as insertion loss, isolation, phase balance, and amplitude balance, will have a great impact on the performance of the entire system.

[0003] The conventional T-junction is a three-port network. The three-port T-type power divider uses narrow-side coupling, and the four-port directional coupler uses wide-side coupling. Because the wide side of the waveguide is larger than the narrow side, it is generally easier to achieve a large coupling amount with wide-side coupling than with narrow-side coupling. The coupling holes are in the form of single-hole coupling, multi-hole coupling, and cross-hole coupling. The appropriate coupling hole can be selected according to the actual situation. The traditional multi-hole directional coupler can improve the bandwidth and isolation, but the spacing of its holes is one-quarter of the waveguide wavelength, resulting in a large volume occupied by the common wide wall of the main and sub-waveguides, which is not suitable for the application of waveguide slow-wave lines. In addition, the existing method has a complex structure and a large volume to achieve multi-channel input, and is not easy to process and form, which greatly reduces its applicability.

[0004] It is easy to achieve a small coupling amount of a waveguide coupler, but it is difficult to achieve a large coupling amount and high isolation. It is difficult to achieve a large coupling amount by opening multiple small holes. Therefore, a waveguide coupler that can achieve high isolation and wide bandwidth is needed. Summary of the invention

[0005] The purpose of the present invention is to provide a high isolation waveguide coupler, which adopts a cross-coupling hole coupling mode for the main waveguide and the coupling branch waveguide, and the cross-coupling hole can meet the needs of large coupling amount and high isolation. And the empty waveguide at the coupling end is connected to the multi-way power divider through a coupling probe, so that the standing wave ratio of the output coupling port of the multi-way power divider is small, and the overall size of the whole coupler is small, which is suitable for occasions with high requirements on the size and performance of the coupler.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A high-isolation waveguide coupler comprises a main waveguide, a coupling branch waveguide, a coupling probe and a power divider;

[0008] The main waveguide and the coupling branch waveguide are perpendicular to each other and isolated, and are connected through at least one cross coupling hole, and the cross coupling hole is arranged on the diagonal line of the overlap area of ​​the wide sides of the main waveguide and the coupling branch waveguide;

[0009] The wide side of the coupling branch waveguide is opened, and the coupling probe passes through the wide side opening perpendicular to the plane where the wide side of the coupling branch waveguide is located. The power divider is connected to the coupling branch waveguide through the coupling probe.

[0010] Furthermore, it comprises two cross coupling holes, both of which are arranged on the diagonal lines of the overlapping area of ​​the wide sides of the main waveguide and the coupling branch waveguide, and the cross directions of the two coupling holes are parallel to the axis where the wide side of the main waveguide is located.

[0011] Furthermore, when the cross coupling hole is processed, the vertical edge line where the cross of the cross coupling hole is located is processed into a chamfered structure.

[0012] Furthermore, the radius of curvature of the chamfered structure is less than or equal to 0.5 mm.

[0013] Furthermore, the main waveguide includes at least one section of main input waveguide and main empty waveguide and at least one section of main output waveguide installed on the same axis; the main input waveguide and the main output waveguide are connected through the main empty waveguide;

[0014] The coupling branch waveguide includes a coupling branch empty waveguide and a coupling end empty waveguide;

[0015] The main empty waveguide and the coupling branch empty waveguide are connected through at least one coupling hole, and the cross coupling hole is arranged in the wide side overlap area of ​​the main hole waveguide and the coupling branch empty waveguide.

[0016] Furthermore, the multi-way power divider includes a plurality of microstrip lines, and the input end of each microstrip line is connected to a coupling probe. In order to achieve multi-way coupling, the multi-way power divider includes a plurality of microstrip lines. According to the required multi-way conditions, the microstrip line can be in the form of a multi-way power divider. If the multi-way coupling degree requirements are different, an unequal power divider can be used. The input end of each microstrip line is connected to a coupling probe.

[0017] Furthermore, in order to improve the electrical performance index of the coupling port, chip resistors are welded between the microstrip lines to improve the standing wave ratio and coupling flatness of the coupling port. The common end of the output ends of several microstrip lines is provided with a chip resistor, and the output end of each microstrip line is connected to the corresponding coaxial coupling port of each microstrip line through the chip resistor.

[0018] Furthermore, a cavity is arranged above the wide side of the hollow waveguide at the coupling end, a microstrip substrate is welded to the bottom surface of the cavity, a microstrip line is welded to the microstrip substrate, and the coupling probe penetrates the cavity and the microstrip substrate to connect with the microstrip line.

[0019] Furthermore, in order to reduce the size of the cavity, the microstrip line is welded on the microstrip substrate in a bending and folding manner to reduce the size.

[0020] Furthermore, the microstrip substrate is parallel to the wide side of the main waveguide, and the coupling probe is perpendicular to the plane where the wide side of the empty waveguide at the coupling end is located.

[0021] Furthermore, the coupling probe includes a glass insulator or a circular, square or other polygonal probe.

[0022] The present invention has the beneficial effects:

[0023] The invention discloses a high-isolation waveguide coupler, comprising a main waveguide and a coupling branch waveguide, wherein the coupling branch empty waveguides are perpendicular to the main empty waveguides and isolated from each other, and a cross coupling hole is used to connect the main waveguide and the coupling branch waveguide, and the cross coupling hole is located on the diagonal line of the overlap area of ​​the wide sides of the main waveguide and the coupling branch waveguide. The cross coupling hole is equivalent to a plurality of single coupling holes, and the size of the coupling hole can be expanded to the maximum extent, thereby expanding the coupling amount, improving the isolation, and realizing high isolation.

[0024] The power divider uses microstrip lines. In order to improve the electrical performance indicators of the coupling port, chip resistors are welded between the microstrip lines to improve the standing wave ratio and coupling flatness of the coupling port. In order to facilitate processing, a vertical hole is opened on the wide side of the hollow waveguide at the coupling end; the coupling port is connected to the multi-way power divider through a glass insulator or a probe, realizing a compact coupler with a small volume, wide bandwidth, low insertion loss, and high power capacity. The multi-way power divider uses microstrip lines to achieve the effect of a multi-way power divider, and in order to reduce the size of the cavity, the microstrip line is bent and folded to reduce the size. This compact multi-way coupler can be used in situations where the size and electrical energy indicators of the coupler are required to be high. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the overall structure of a waveguide coupler provided by an embodiment of the present invention;

[0026] Figure 2 A top view of a coupling hole structure of a waveguide coupler provided by an embodiment of the present invention;

[0027] Figure 3 A top view of another coupling hole structure of a waveguide coupler provided by an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of a coupling curve of a multi-way coupler provided in an embodiment of the present invention.

[0029] The corresponding names in the attached drawings are:

[0030] 1-main input waveguide, 2-main empty waveguide, 3-main output waveguide, 4-isolation end waveguide, 5-coupling branch empty waveguide, 6-coupling end empty waveguide, 7-coupling hole, 8-coupling probe, 9-cavity, 10-microstrip substrate, 11-multi-way power divider, 12-chip resistor, 13-coaxial coupling port, 14-coupling probe via. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0033] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0034] Additionally, descriptions of well-known structures, functions, and configurations may be omitted for clarity and conciseness.One of ordinary skill in the art will recognize that various changes and modifications may be made to the examples described herein without departing from the spirit and scope of the present disclosure.

[0035] Technologies, methods, and apparatus known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the authorization specification.

[0036] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0037] Example 1

[0038] like Figure 1 As shown, this embodiment provides a high isolation waveguide coupler, including a main waveguide, a coupling branch waveguide, a coupling probe 8 and a power divider;

[0039] The main waveguide and the coupling branch waveguide are perpendicular to each other and isolated, and are connected through at least one cross coupling hole 7, and the cross coupling hole 7 is arranged on the diagonal line of the overlap area of ​​the wide sides of the main waveguide and the coupling branch waveguide;

[0040] The wide side of the coupling branch waveguide is opened, and the coupling probe 8 passes through the wide side opening perpendicular to the plane where the wide side of the coupling branch waveguide is located. The power divider is connected to the coupling branch waveguide through the coupling probe 8.

[0041] Specifically, in a specific embodiment, the main waveguide includes at least one section of main input waveguide 1 and main empty waveguide 2 and at least one section of main output waveguide 3 installed on the same axis; the main input waveguide 1 is connected with the main output waveguide 3 through the main empty waveguide 2; the coupling branch waveguide includes a coupling branch empty waveguide 5 and a coupling end empty waveguide 6; the main empty waveguide 2 and the coupling branch empty waveguide 5 are connected through at least one coupling hole 7, and the cross coupling hole 7 is arranged in the wide side overlap area of ​​the main hole waveguide and the coupling branch empty waveguide 5.

[0042] A cavity 9 is provided above the wide side of the empty waveguide 6 at the coupling end, a microstrip substrate 10 is welded to the bottom surface of the cavity 9, a microstrip line is welded to the microstrip substrate 10, and the coupling probe 8 penetrates the cavity 9 and the microstrip substrate 10 and is connected to the microstrip line. The microstrip substrate 10 is parallel to the wide side of the main waveguide, and the coupling probe 8 is perpendicular to the plane where the wide side of the empty waveguide 6 at the coupling end is located.

[0043] The multi-way power divider 11 includes several microstrip lines, and the input end of each microstrip line is connected to the coupling probe 8. In order to achieve multi-way coupling, the multi-way power divider 11 includes several microstrip lines. According to the required multi-way conditions, the microstrip line can be in the form of a multi-way power divider. If the multi-way coupling degree requirements are different, it can be implemented in the form of an unequal power divider. For example, the microstrip line can be a one-to-two power divider, or a multi-way power divider. The input end of each microstrip line is connected to the coupling probe 8. In order to improve the electrical performance indicators of the coupling port, the chip resistor 12 is welded between the microstrip lines to improve the standing wave ratio and coupling flatness of the coupling port. The common end of the output end of several microstrip lines is provided with a chip resistor 12, and the output end of each microstrip line is respectively connected to the coaxial coupling port 13 corresponding to each microstrip line through the chip resistor 12. In order to reduce the size of the cavity 9, the microstrip line is welded on the microstrip substrate 10 in a bending and folding manner to reduce the size.

[0044] Specifically, in a specific embodiment, two cross coupling holes 7 are used, and the two cross coupling holes 7 are both arranged on the diagonal lines of the overlap area of ​​the wide sides of the main waveguide and the coupling branch waveguide, and the cross directions of the two coupling holes 7 are parallel to the axis where the wide sides of the main waveguide are located. When the cross coupling hole 7 is processed, the vertical edge line where the cross of the cross coupling hole 7 is located is processed into a chamfered structure. And the curvature radius of the chamfered structure ranges from several millimeters to 0.5 millimeters. It can be seen from the figure that the center of the cross coupling hole 7 is located on the diagonal line of the common wall of the main empty waveguide 2 and the coupling branch empty waveguide 5, and the cross coupling hole 7 can be rotated around its own center by 0° to 90°.

[0045] It can be understood that, since the single-hole directional coupler has a relatively narrow bandwidth in terms of directivity, a series of coupling holes 7 can be designed to form an array, and several arrays can be superimposed to combine the coupling degree and the directional response. By superimposing the directivity of the small hole and the directivity of the array at the coupling end and the isolation end, better directivity can be obtained, and this additional degree of freedom can also increase the bandwidth. Therefore, in order to increase the coupling performance of the coupling hole 7, the coupling holes 7 can be connected to form a cross coupling hole 7. The traditional single hole and multiple holes are improved into double cross coupling holes 7. The double cross coupling holes 7 are rotated by a certain angle and are located on the diagonal of the waveguide common wall of the main empty waveguide 2 and the coupling branch empty waveguide 5, maximizing the length of the hole, thereby expanding the coupling amount. The double cross coupling hole 7 is equivalent to a plurality of coupling holes 7, which can improve the isolation and achieve high isolation. By adjusting the position of the cross coupling hole on the diagonal of the waveguide common wall, high amplitude consistency can be further achieved.

[0046] In a specific embodiment, the coupling branch waveguide further comprises an isolation end waveguide 4 located perpendicular to the installation axis of the main waveguide, and the isolation end waveguide 4 and the coupling end empty waveguide 6 are connected through the coupling branch empty waveguide 5. Microwave absorbing material is arranged inside the isolation end waveguide 4 or a waveguide load is externally connected. The coupling probe 8 comprises a glass insulator or a probe, and the probe comprises a circular, square or other polygonal probe.

[0047] like Figure 3 As shown, a processed waveguide coupler is provided. It can be seen that the main input waveguide 1 and the main output waveguide 3 are connected through the main empty waveguide 2; the main empty waveguide 2 and the coupling branch empty waveguide 5 are directly connected through the cross coupling hole 7; the isolation end waveguide 4 of the coupling branch waveguide has a built-in microwave absorbing material or an external waveguide load, and the coupling end waveguide has a via provided on the wide side of the waveguide to be connected to one end of the coupling probe 8; the other end of the glass insulator penetrates into the cavity 9 and is connected to the bottom surface of the microstrip substrate 10, the glass insulator penetrates the microstrip substrate 10 and is welded to the microstrip line, two microstrip lines are welded on the microstrip substrate 10 in a bent and folded manner, and the common end where one end of the two microstrip lines intersects is connected to the glass insulator penetrating the cavity 9 and the microstrip substrate 10, the output ends of the two microstrip lines are connected to a chip resistor 12, and a chip resistor 12 is welded between the output end of the microstrip line and the coaxial coupling port 13, so that the coaxial connector is welded through the two coaxial coupling ports 13. It can be seen that the coaxial coupling port 13 is related to the setting of the microstrip line. If the microstrip line is set as a one-to-two power splitter, there are two coaxial coupling ports 13. If the microstrip line is a multi-way power splitter, the number of ports of the coaxial coupling port 13 corresponds to the multi-way power splitter.

[0048] It can be understood that in the overall concept of the present application, since the waveguide size is large in the prior art during multi-path coupling, the input and output dimensions of the coupler are long. The present application reduces the size by using a cross-coupling method for the main waveguide and the coupling branch waveguide, and the glass insulator connected to the coupling branch waveguide is perpendicular to the plane where the wide side of the coupling end empty waveguide 6 is located. The cavity 9 is set above the coupling end empty waveguide 6 and parallel to the main waveguide, and the microstrip substrate 10 is parallel to the plane where the wide side of the coupling end empty waveguide 6 is located. The microstrip line on the microstrip substrate 10 is welded in a bending and folding manner to reduce the size of the cavity 9, thereby reducing the size of the entire coupler, and obtaining a small coupler with high isolation.

[0049] In order to better illustrate the beneficial effects of this application, Figure 3 A coupling curve obtained by coupling calculation based on the above design is given. It can be seen from the figure that the coupling fluctuation is small within the passband frequency while the coupler realizes two-way coupling output. And the coupling characteristics of the compact coupling can be easily optimized by adjusting the length of the glass insulator probe and the width of the microstrip line.

[0050] In order to describe the present invention, more implementation examples can be cited. In order to realize the above implementation examples, although the microstrip line and the coupling end waveguide are connected by a glass insulator, they can also be connected by a circular, square or other polygonal probe. And during processing, for the vertical edges that need to be chamfered in the coupler, for example, when a CNC milling machine is used for processing, the internal vertical edges need to be chamfered. The radius of curvature of the chamfer is several millimeters to 0.5 millimeters. In principle, all implementations that comply with the claims herein belong to the content disclosed in the present invention.

[0051] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. According to the technical essence of the present invention, within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the present invention.

Claims

1. A high isolation waveguide coupler, characterized in that: It comprises a main waveguide, a coupled branch waveguide, a coupled probe (8) and a multi-channel power distributor (11); The main waveguide and the coupling branch waveguide are perpendicular to each other and isolated, and are connected via at least one cross coupling hole (7), wherein the cross coupling hole (7) is arranged on a diagonal line of a wide side overlap area of ​​the main waveguide and the coupling branch waveguide; The wide side of the coupling branch waveguide has an opening, the coupling probe (8) passes through the wide side opening perpendicular to the plane where the wide side of the coupling branch waveguide is located, and the multi-channel power distributor (11) is connected to the coupling branch waveguide via the coupling probe (8); The coupling branch waveguide comprises an isolation end waveguide (4) located perpendicular to the main waveguide installation axis, a coupling branch empty waveguide (5) and a coupling end empty waveguide (6); the isolation end waveguide (4) and the coupling end empty waveguide (6) are connected via the coupling branch empty waveguide (5); a microwave absorbing material is disposed inside the isolation end waveguide (4) or a waveguide load is externally connected; The multi-channel power distributor (11) comprises a plurality of microstrip lines, the input end of each microstrip line is connected to a coupling probe (8), a cavity (9) is arranged above the wide side of the hollow waveguide (6) at the coupling end, a microstrip substrate (10) is welded to the bottom surface of the cavity (9), the microstrip line is welded to the microstrip substrate (10), and the coupling probe (8) penetrates the cavity (9) and the microstrip substrate (10) to be connected to the microstrip line.

2. A high isolation waveguide coupler according to claim 1, characterized in that: It comprises two cross coupling holes (7), the two cross coupling holes (7) are both arranged on the diagonal lines of the overlap area of ​​the wide sides of the main waveguide and the coupling branch waveguide, and the cross directions of the two coupling holes (7) are parallel to the axis where the wide side of the main waveguide is located.

3. A high isolation waveguide coupler according to claim 1, characterized in that: When the cross coupling hole (7) is processed, the vertical edge line where the cross of the cross coupling hole (7) is located is processed into a chamfered structure.

4. A high isolation waveguide coupler according to claim 3, characterized in that: The curvature radius of the chamfered structure is less than or equal to 0.5 mm.

5. The high isolation waveguide coupler according to claim 1, characterized in that: The main waveguide comprises at least one section of main input waveguide (1) and a main empty waveguide (2) and at least one section of main output waveguide (3) installed on the same axis; the main input waveguide (1) and the main output waveguide (3) are connected via the main empty waveguide (2); The coupling branch waveguide comprises a coupling branch empty waveguide (5) and a coupling end empty waveguide (6); The main path empty waveguide (2) and the coupling branch empty waveguide (5) are connected via at least one coupling hole (7), and the cross coupling hole (7) is arranged in the wide side overlap area of ​​the main path hole waveguide and the coupling branch empty waveguide (5).

6. The high isolation waveguide coupler according to claim 1, characterized in that: A chip resistor (12) is provided at the common end of the output ends of a plurality of microstrip lines, and the output end of each microstrip line is connected to a corresponding coaxial coupling port (13) of each microstrip line through the chip resistor (12).

7. The high isolation waveguide coupler according to claim 1, characterized in that: The microstrip substrate (10) is parallel to the wide side of the main waveguide, and the coupling probe (8) is perpendicular to the plane where the wide side of the coupling end empty waveguide (6) is located.

8. The high isolation waveguide coupler according to claim 1, characterized in that: The coupling probe (8) comprises a glass insulator or a circular, square or other polygonal probe.

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