A microwave program-controlled step attenuator

Abstract

The present application provides a microwave programmable step attenuator, including several levels of step length switching units; the step length switching unit includes a fixed straight-through piece, at least two attenuation pieces arranged at intervals above the straight-through piece, and a group of movable spring pieces respectively located at both ends of the attenuation piece; each movable spring piece is respectively connected to a push rod, which is arranged to move along its own axis and is used to drive the movable spring piece so that the inner end of the movable spring piece contacts the attenuation piece or the straight-through piece; the outer end of the movable spring piece is rotatably connected to one end of the fixed fixed spring piece through a rotating column, and the push rod is rotatably arranged around the rotating column corresponding to the movable spring piece connected thereto, and is used to drive the movable spring piece to rotate so that the inner end of the movable spring piece switches to a different attenuation piece; the other end of the fixed spring piece is rotatably connected to the outer end of the movable spring piece of the adjacent first-level step length switching unit through a rotating column, or is vertically connected to a radio frequency connector. The scheme of the present application can realize multi-level step length switching, and can also maintain good stability on the basis of realizing switching.

Description

Technical Field

[0001] The present application belongs to the field of radio frequency microwave technology, and relates to a microwave programmable step attenuator, and in particular to a microwave programmable step attenuator with switchable step length. Background Art

[0002] Microwave programmable step attenuators are mainly used to adjust the RF signal amplitude in microwave test systems. They can adjust the signal level to the desired level, thereby achieving impedance matching of the RF circuit and isolation protection for subsequent devices. They are widely used in microwave communication systems with gain setting and control function requirements, such as spectrum analyzers, vector network analyzers, synthetic signal sources, etc.

[0003] Microwave programmable step attenuator generally consists of three parts: microwave signal processing part, actuator, control circuit and external programmable signal interface.

[0004] The microwave signal processing part is mainly responsible for the input and output of microwave signals, power attenuation, microwave transmission and other functions. It is the main path of microwave signals and the key part to determine the performance indicators. The input and output parts use coaxial connectors to achieve continuous coverage of the full frequency band. The internal transmission line and the straight-through line use edge lines (a special form of strip lines), which have the characteristics of wide working frequency band and low loss, and can withstand relatively large power. Its biggest advantage is that the center conductor can change its shape without affecting the transmission characteristics, which is the basic condition for realizing the switching function. The edge line is also a common transmission line type for microwave mechanical switches. The attenuation of microwave signals is achieved by attenuation sheets. The attenuation sheet adopts a distributed parameter design, has good attenuation accuracy and attenuation frequency response in a wider frequency band, and matches the edge line through a suspended coplanar waveguide, which can meet high-precision applications such as power calibration. A group of straight-through lines and attenuation sheets constitute an attenuation unit, which can complete a certain attenuation amount. Different combinations of multiple attenuation units can achieve various required attenuations.

[0005] The actuator is composed of several groups of electromagnetic coils and some precision structural parts. After receiving the driving level, it can immediately move to push the edge line to deform, so that the microwave signal changes from the through (attenuation) state to the attenuation (through) state. And when the driving level disappears, it can still rely on magnetic force to maintain the current state. The accuracy and reliability of the actuator directly determine the reliability and repeatability of the programmable step attenuator.

[0006] The control circuit and external program control signal interface provide the power supply and control level required to drive the actuator, and convert the external program control signal into the control level to drive different actuators to achieve attenuation combination. Generally, the switch circuit design is adopted.

[0007] The coaxial connector connection methods of the traditional programmable attenuator are generally divided into two categories: one is that the coaxial connector is connected to the edge line perpendicular to the transmission direction of the RF microwave signal. In this method, in order to reduce the processing requirements for the connector and thus reduce the implementation and preparation costs, the edge line at the connection needs to be bent upward to achieve connection with the connector, but this increases the processing complexity of the edge line and increases the mechanical performance requirements of the edge line, and there is a situation where the bending angle edge line is greatly deformed under the influence of gravity or additional impact, resulting in disconnection from the coaxial connector; the other is that the coaxial connector is parallel to the transmission direction of the RF microwave signal through an elastic contact bellows and connected to the edge line, such as the schemes disclosed in CN116759776A and CN113078430A. Although there is no need for bending, the processing requirements of the edge line are reduced, and the connector and the edge line can be connected more closely through elastic contact, the introduction of the elastic contact bellows will increase the difficulty of assembly, and the processing difficulty of the elastic contact bellows is relatively large, and there is a problem of device performance reduction or disconnection due to life failure.

[0008] At the same time, no matter which method is currently used, when faced with different step length requirements, the internal module structure of the device needs to be replaced separately and reassembled for use, or devices with other step lengths need to be designed separately, which cannot directly meet the switching requirements for different step lengths. Summary of the invention

[0009] In order to solve the shortcomings of the above-mentioned prior art, the present application provides a microwave programmable step attenuator with switchable step length, which realizes multi-level step length switching and can maintain good stability on the basis of switching. It can also reduce the requirements on the performance and processing accuracy of edge line beryllium copper materials, improve the working stability of the programmable attenuator, and reduce the difficulty of assembly.

[0010] In order to achieve the above object, the present invention adopts the following technologies:

[0011] A microwave program-controlled step attenuator comprises a plurality of step length switching units;

[0012] The step length switching unit includes a fixed straight-through piece, at least two attenuation pieces arranged at intervals above the straight-through piece, and a group of movable spring pieces respectively located at two ends of the attenuation piece;

[0013] Each movable spring piece is connected to a push rod, which is arranged to move along its own axis and is used to drive the movable spring piece so that the inner end of the movable spring piece contacts the attenuation piece or the straight-through piece;

[0014] The outer end of the moving spring is rotatably connected to one end of a fixed spring through a rotating column, and the push rod is rotatably arranged around the rotating column corresponding to the moving spring connected thereto, and is used to drive the moving spring to rotate so that the inner end of the moving spring switches to correspond to different attenuation sheets;

[0015] The other end of the fixed spring piece is rotationally connected to the outer end of the movable spring piece of the adjacent first-level step length switching unit through a rotating column, or is vertically connected to the radio frequency connector.

[0016] Furthermore, the movable spring piece and the fixed spring piece are arranged along the length direction of the attenuator, and the attenuation pieces in the step length switching unit are arranged at intervals along the width direction of the attenuator.

[0017] Furthermore, the fixed spring piece is straight, and a through hole is provided at the other end thereof. A convex column is formed at the connecting end of the RF connector, and the convex column is matched with the through hole.

[0018] Furthermore, the movable spring piece includes a first horizontal section, a transition section, and a second horizontal section which are connected in sequence. The inner end of the first horizontal section is used to contact the attenuation piece or the straight-through piece, and the outer end of the second horizontal section is rotatably connected to the fixed spring piece through a rotating column.

[0019] Furthermore, the push rod is connected to the first horizontal section of the movable spring sheet, and a through hole and a limiting hole connected to the through hole are provided on the first horizontal section. The width or diameter of the limiting hole is smaller than the diameter of the through hole. An annular groove is provided on the top of the push rod, and the bottom diameter of the annular groove is smaller than the width or diameter of the limiting hole. The outer diameter of the lower side wall of the annular groove is larger than the diameter of the through hole. A limiting head is formed above the upper side wall of the annular groove, and the outer diameter of the limiting head is smaller than the diameter of the through hole and larger than the width or diameter of the limiting hole. When used, the annular groove cooperates with the limiting hole.

[0020] Furthermore, the through piece is horizontally mounted on the first support column and passes through the first dielectric column at the top of the first support column, the fixed spring piece is horizontally mounted on the second support column and passes through the second dielectric column at the top of the second support column, and the first support column and the second support column are mounted on the dielectric bottom plate. An air cavity is provided on the dielectric bottom plate, and the step length switching unit is in the air cavity. A channel is provided through the dielectric bottom plate, and the push rod passes through the channel.

[0021] The beneficial effects of the present invention are:

[0022] 1. A design scheme for an attenuator structure that can switch between different step lengths is provided, which overcomes the attenuator structure design of the traditional attenuator with only one fixed step length, and does not significantly increase the structural size of the entire attenuator; and except for the attenuation sheets added for configuring different attenuation amounts, no additional structural parts are introduced, and the push rod is set to be movable along the axis and rotatable along the rotation axis of the connection between the moving spring sheet and the fixed spring sheet, so as to realize the horizontal displacement of the moving spring sheet, and then realize the step length switching, the structure is simple and ingenious, and the switching process will not bring vertical / vertical force to affect the stability of the moving spring sheet;

[0023] 2. The solution of the present invention can be further expanded into a multi-stage structure, and a design with more attenuation combinations can be realized through a multi-stage step length switching unit, further improving the application range of the attenuator;

[0024] 3. The connection structure between the connector and the fixed spring sheet (i.e., edge line) is improved. There is no need to bend the edge line, and the mechanical properties of the beryllium copper material of the edge line are lower, which reduces the cost of the beryllium copper material and avoids the disconnection of the coaxial connector caused by the large deformation of the bending angle edge line under the influence of gravity or additional impact. At the same time, there is no need to add an additional elastic bellows, which saves the cost of parts and reduces the difficulty of assembling the connector. At the same time, it can also avoid the problem of difficult production and processing brought by the bellows as a high-precision device, and can also ignore the performance degradation and disconnection of the device due to the failure of the bellows during its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a three-dimensional diagram of the internal structure of the microwave programmable step attenuator according to an embodiment of the present application.

[0026] Figure 2 yes Figure 1 Magnified view of section A in .

[0027] Figure 3 This is a stereoscopic diagram from another perspective of the internal structure of the microwave programmable step attenuator of an embodiment of the present application.

[0028] Figure 4 It is a top view of the internal structure of the microwave programmable step attenuator according to an embodiment of the present application.

[0029] Figure 5 It is a side view of the internal structure of the microwave programmable step attenuator according to an embodiment of the present application having a multi-stage step length switching unit.

[0030] Figure 6 This is a simulation effect diagram of the microwave programmable step attenuator connector and the fixed spring piece connected through a convex column and a through hole in an embodiment of the present application.

[0031] Figure markings: 1-RF connector, 11-convex column, 2-fixed spring sheet, 23-rotating column, 3-moving spring sheet, 31-contact portion, 32-through hole, 33-limiting hole, 4-push rod, 41-annular groove, 42-limiting head, 5-attenuation plate, 6-second supporting column, 61-second dielectric column, 7-through plate, 71-connecting portion, 8-first supporting column, 81-first dielectric column, 9-dielectric bottom plate, 90-channel. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the implementation modes of the present invention are described in detail below with reference to the accompanying drawings. However, the embodiments described in the present invention are only part of the embodiments of the present invention, rather than all the embodiments.

[0033] The embodiment of the present application provides a microwave programmable step attenuator, including a plurality of step length switching units, such as Figure 1 , Figure 3 , Figure 4 The example shown is a one-stage step length switching unit. Figure 5 The example of a two-stage step length switching unit is shown. The following will be described in detail using the first and second stages as examples. Of course, as a specific implementation form, it can also be more than two stages, which can be derived based on the setting method of the second stage, and will not be repeated here.

[0034] Specifically, the step length switching unit includes a fixed straight-through piece 7 (also known as a straight-through line), at least two attenuation pieces 5 arranged at intervals above the straight-through piece 7, and a group of movable spring pieces 3 respectively located at both ends of the attenuation piece 5; specifically, this example only shows the case where there are two attenuation pieces 5, and according to actual applications, there can be more than two cases, and the arrangement can be increased according to the principle of this example.

[0035] Specifically, the through sheet 7 is horizontally mounted on the first support column 8 and is provided through the first dielectric column 81 on the top of the first support column 8. The first support column 8 is mounted on the dielectric bottom plate 9. An air cavity is provided on the dielectric bottom plate 9, and the step length switching unit is located in the air cavity. A channel 90 is provided through the dielectric bottom plate 9.

[0036] The attenuation sheet 5 is arranged parallel to the predetermined distance above the straight-through sheet 7, the inner end of the movable spring sheet 3 is located between the attenuation sheet 5 and the straight-through sheet 7, each movable spring sheet 3 is connected with a push rod 4, and the push rod 4 is arranged to vertically penetrate the channel 90. Specifically, the lower part of the dielectric bottom plate 9 penetrates into the air cavity and is arranged to move along its own axis to drive the inner end of the movable spring sheet 3 to contact the attenuation sheet 5 or the straight-through sheet 7. Specifically, the inner end of the movable spring sheet 3 has a contact portion 31, and the two ends of the bottom surface of the attenuation sheet 5 have contact areas for contacting with the contact portion 31 of the movable spring sheet 3 to form a conductive link, and the straight-through sheet 7 has a connection portion 71 for contacting and conducting with the contact portion 31 of the movable spring sheet 3 at a corresponding position below each attenuation sheet 5.

[0037] A second support column 6 is provided on the dielectric bottom plate 9 , and a fixed spring piece 2 (ie, an edge line) is horizontally mounted on the second support column 6 . The fixed spring piece 2 is passed through a second dielectric column 61 at the top of the second support column 6 .

[0038] The movable spring piece 3 and the fixed spring piece 2 are arranged along the length direction of the attenuator, and the attenuation pieces 5 in the step length switching unit are arranged at intervals along the width direction of the attenuator.

[0039] The outer end of the movable spring piece 3 is rotatably connected to one end of the fixed spring piece 2 through a rotating column 23. The push rod 4 is rotatably arranged around the rotating column 23 corresponding to the movable spring piece 3 connected thereto, and is used to drive the movable spring piece 3 to rotate so that the inner end of the movable spring piece 3 switches to correspond to a different attenuation piece 5.

[0040] For the case where there is only one level of step length switching unit, such as Figure 1 As shown, the other end of the fixed spring piece 2 is directly connected to the RF connector 1 vertically. Figure 5 As shown, the other end of the fixed spring piece 2 closest to the two ends in the length direction of the attenuator / air cavity is vertically connected to the RF connector 1, and the other fixed spring pieces 2 between adjacent step length switching units are rotatably connected to the outer end of the movable spring piece 3 of the adjacent first-level step length switching unit through a rotating column 23.

[0041] Preferably, the conventional connector and edge line connection method is improved in this embodiment, such as Figure 2 As shown, the fixed spring piece 2 is straight, and a through hole is provided at the other end. A protrusion 11 is formed at the connection end of the RF connector 1. The protrusion 11 fits in the through hole, and then the fitting is fixed by conductive glue or welding. This structure can not only reduce the requirements for the performance and processing accuracy of the edge line beryllium copper material, improve the working stability of the programmable attenuator, but also reduce the difficulty of assembly without changing the fixed size of the attenuator. Figure 6 The figure shows the simulation results of this connection method. s(1,1) is the reflection coefficient. It can be seen that the standing wave basically meets the usage requirements of DC-26.5GHz.

[0042] For details, see Figure 1-Figure 3 The movable spring piece 3 includes a first horizontal section, a transition section, and a second horizontal section which are connected in sequence. The contact portion 31 is located at the inner end of the first horizontal section and is used to contact the attenuation piece 5 or the straight-through piece 7. The outer end of the second horizontal section is rotatably connected to the fixed spring piece 2 through the rotating column 23.

[0043] The push rod 4 is connected to the first horizontal section of the movable spring 3, so that when the push rod 4 moves vertically, the movable spring 3 matches the vertical movement change through the middle transition section, so that the first horizontal section and the second horizontal section can be kept in a horizontal posture to a large extent, which is beneficial to maintaining the contact effectiveness between the contact portion 31 and the horizontally arranged attenuation plate 5 or the straight-through plate 7, and is also beneficial to maintaining the stability of the rotational connection between the outer end of the second horizontal section and the horizontal fixed spring 2.

[0044] As one of the more specific embodiments, a through hole 32 and a limit hole 33 connected to the through hole 32 are provided on the first horizontal section. The through hole 32 is used for the upper part of the push rod 4 to pass through, and the limit hole 33 is used for the push rod 4 to be inserted, forming upper and lower limits, so that when the push rod 4 moves vertically or rotates along the rotating column 23, it can effectively drive the dynamic spring 3 to move. Specifically, the limiting hole 33 can be a strip hole or a circular hole. The hole width or aperture of the limiting hole 33 is smaller than the aperture of the through hole 32. A ring groove 41 is provided on the top of the push rod 4. The bottom diameter of the ring groove 41 is smaller than the hole width or aperture of the limiting hole 33. The outer peripheral diameter of the lower side wall of the ring groove 41 is larger than the aperture of the through hole 32. A limiting head 42 is formed above the upper side wall of the ring groove 41. The outer peripheral diameter of the limiting head 42 is smaller than the aperture of the through hole 32, but larger than the hole width or aperture of the limiting hole 33. When used, after the limiting head 42 passes through the through hole 32, the lower side wall of the ring groove 41 abuts against the bottom surface of the movable spring piece 3, and then the push rod 4 is moved to make the ring groove 41 cooperate with the limiting hole 33, so that the upper and lower side walls of the limiting hole 33 form a limitation on the movable spring piece 3. Specifically, the thickness of the movable spring piece 3 and the size of the ring groove 41 can be reasonably designed according to actual needs.

[0045] When used, the push rod 4 can be moved along its own axial direction to switch the movable spring piece 3 between the attenuation piece 5 and the straight-through piece 7. At the same time, the push rod 4 can be rotated along the rotating column 23 to make the movable spring piece 3 move horizontally to switch between different attenuation pieces 5. Figure 5 As shown, when there are two-stage step length switching units, multiple attenuation combination designs can be realized through the horizontal displacement of the movable spring 3 by the push rod 4 in each step length switching unit. Furthermore, according to this structural mode, multiple step length switching units are connected in series to achieve more attenuation combinations, greatly improving the application range of the programmable step attenuator.

[0046] The scheme of this example can ensure that the programmable attenuator has good working performance in the range of DC-26.5GHz. At the same time, it provides an attenuator structure design scheme that can switch different step lengths, provides new ideas for more attenuation combinations, and has a multi-level step length switching design, which greatly improves the application range of the programmable step attenuator.

[0047] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application.

Claims

1. A microwave program-controlled step attenuator, characterized in that: It includes several levels of step length switching units; The step length switching unit comprises a fixed straight-through piece (7), at least two attenuation pieces (5) arranged at intervals above the straight-through piece (7), and a group of movable spring pieces (3) respectively located at two ends of the attenuation piece (5); Each movable spring piece (3) is respectively connected to a push rod (4), and the push rod (4) is arranged to move along its own axis and is used to drive the inner end of the movable spring piece (3) to contact the attenuation piece (5) or the straight-through piece (7); The outer end of the movable spring piece (3) is rotatably connected to one end of a fixedly arranged fixed spring piece (2) via a rotating column (23); the push rod (4) is rotatably arranged around the rotating column (23) corresponding to the movable spring piece (3) connected thereto, and is used to drive the movable spring piece (3) to rotate so that the inner end of the movable spring piece (3) switches to correspond to a different attenuation piece (5); The other end of the fixed spring piece (2) is rotationally connected to the outer end of the movable spring piece (3) of the adjacent first-level step length switching unit via a rotating column (23), or is vertically connected to the radio frequency connector (1); The movable spring piece (3) and the fixed spring piece (2) are arranged along the length direction of the attenuator, and the attenuation pieces (5) in the step length switching unit are arranged at intervals along the width direction of the attenuator.

2. The microwave program-controlled step attenuator according to claim 1, characterized in that: The fixed spring piece (2) is straight, and a through hole is provided at the other end thereof. A convex column (11) is formed at the connection end of the radio frequency connector (1), and the convex column (11) is matched with the through hole.

3. The microwave programmable step attenuator according to claim 1, characterized in that: The movable spring piece (3) comprises a first horizontal section, a transition section, and a second horizontal section which are connected in sequence. The inner end of the first horizontal section is used to contact the attenuation piece (5) or the straight-through piece (7), and the outer end of the second horizontal section is rotatably connected to the fixed spring piece (2) via a rotating column (23).

4. The microwave program-controlled step attenuator according to claim 3, characterized in that: The push rod (4) is connected to the first horizontal section of the movable spring sheet (3). The first horizontal section is provided with a through hole (32) and a limiting hole (33) connected to the through hole (32). The hole width or hole diameter of the limiting hole (33) is smaller than the hole diameter of the through hole (32). The top of the push rod (4) is provided with an annular groove (41). The groove bottom diameter of the annular groove (41) is smaller than the hole width or hole diameter of the limiting hole (33). The outer peripheral diameter of the lower side wall of the annular groove (41) is larger than the hole diameter of the through hole (32). A limiting head (42) is formed above the upper side wall of the annular groove (41). The outer peripheral diameter of the limiting head (42) is smaller than the hole diameter of the through hole (32) and larger than the hole width or hole diameter of the limiting hole (33). When used, the annular groove (41) is matched with the limiting hole (33).

5. The microwave programmable step attenuator according to claim 1, characterized in that: The straight-through sheet (7) is horizontally mounted on the first support column (8) and is passed through the first dielectric column (81) at the top of the first support column (8); the fixed spring sheet (2) is horizontally mounted on the second support column (6) and is passed through the second dielectric column (61) at the top of the second support column (6); and the first support column (8) and the second support column (6) are mounted on the dielectric bottom plate (9).

6. The microwave program-controlled step attenuator according to claim 5, characterized in that: A channel (90) is provided through the medium bottom plate (9), and the push rod (4) is arranged through the channel (90).

7. The microwave programmable step attenuator according to claim 5, characterized in that: An air cavity is provided on the dielectric bottom plate (9), and the step length switching unit is located in the air cavity.

8. The microwave programmable step attenuator according to claim 1, characterized in that: The step length switching unit comprises two attenuation plates (5) arranged at intervals.

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