A dielectric support for a transmission line for a broadband coaxial switch, the transmission line

Abstract

The application provides a kind of wideband coaxial switch transmission line medium support, transmission line, it is related to microwave communication technical field, to solve one of the technical problems that medium support is difficult to adapt wideband, structural strength is not high, high order mode affects microwave transmission performance.The medium support, including the body of the outer contour is regular hexagonal prism, the body has central through hole;U-shaped recess is formed on the six sides of the body, and the recess extends along the axial direction of the body and is recessed towards the center of the body;The orthographic projection of the recess on the first plane includes a semicircular segment and two opposite straight segments, one end of each straight segment intersects with the first line segment, and the other end is tangent to the corresponding end of the semicircular segment.The working frequency band of the medium support is wide, the structural strength meets the support requirements, and the microwave transmission performance can be improved.

Description

Technical Field

[0001] This invention relates to the field of microwave communication technology, and in particular to a dielectric support and transmission line for a broadband coaxial switch. Background Technology

[0002] Dielectric supports are essential components in microwave switches and connectors that enable microwave transmission. Their function is to provide physical support between the inner and outer conductors, ensuring good coaxiality when they are assembled and guaranteeing impedance matching characteristics during signal transmission. Changes in the dielectric at the dielectric support point along the microwave transmission path of a coaxial transmission line can cause reflections and losses, especially at higher operating frequencies, severely degrading microwave transmission characteristics.

[0003] In related technologies, dielectric supports are generally simple cylindrical structures or through holes in cylindrical dielectrics. This type of dielectric support is suitable for low-frequency bands or products with low requirements for standing waves and losses. When the operating bandwidth is wide, the dimensions of the inner conductor, outer conductor, and dielectric support of the transmission line are all small. This type of dielectric support will introduce impedance discontinuities at high frequencies, and the standing waves and losses will deteriorate sharply. Summary of the Invention

[0004] The purpose of this invention is to provide a dielectric support and transmission line for a broadband coaxial switch, so as to solve one of the technical problems of dielectric support being difficult to adapt to broadband, low structural strength, and generating high-order modes that affect microwave transmission performance.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a dielectric support for a transmission line for a broadband coaxial switch, comprising a body having an outer contour of a regular hexagonal prism, the body having a central through hole; Each of the six sides of the body has a U-shaped recess, which extends along the central axis of the body and is recessed toward the central axis of the body. The orthographic projection of the recess onto a first plane includes a semicircular segment and two opposing straight segments. One end of each straight segment intersects a first line segment, and the other end is tangent to the corresponding end of the semicircular segment. The first plane is perpendicular to the axial direction, and the first line segment is the orthographic projection of the side surface onto the first plane. The center of the semicircular segment lies on the perpendicular bisector of the first line segment. The body has ribs that separate two adjacent recesses, and grooves are formed on the end faces of the ribs.

[0006] According to at least one embodiment of the present invention, the diameter of the semicircular segment is smaller than the length of the first line segment.

[0007] According to at least one embodiment of the present invention, the outer contour of the end face of the body is a regular hexagon, and the diameter of the circumcircle of the regular hexagon is in the range of 0.8 mm to 1.0 mm.

[0008] According to at least one embodiment of the present invention, the length of the body along the central axis ranges from H to λ. g / 4≤H≤λ g , where λ g The wavelength at 130 GHz is given by the equivalent dielectric constant.

[0009] According to at least one embodiment of the present invention, the dielectric constant of the material of the body is in the range of 2 to 3.6.

[0010] According to at least one embodiment of the present invention, the diameter of the central through hole ranges from 0.2 mm to 0.3 mm.

[0011] According to at least one embodiment of the present invention, the distance between the center of the semicircular segment of the recessed portion as projected onto the first plane and the center of the central through hole as projected onto the first plane ranges from 0.25 mm to 0.4 mm.

[0012] In a second aspect, the present invention provides a transmission line, including the medium support described in the first aspect, wherein the transmission line is a coaxial transmission line.

[0013] According to at least one embodiment of the present invention, the transmission line further includes an inner conductor and an outer conductor, the body being sleeved on the inner conductor and the side edges of the body being supported on the inner wall of the outer conductor.

[0014] According to at least one embodiment of the present invention, the operating frequency band of the transmission line is DC~130GHz.

[0015] In one or more technical solutions provided in the exemplary embodiments of the present invention, at least one of the following beneficial effects can be achieved.

[0016] The dielectric support for a broadband coaxial switch transmission line provided in an exemplary embodiment of the present invention includes a body with an outer contour of a regular hexagonal prism, a central through hole, and a groove on the end face of the dielectric support body. The orthographic projection of the groove onto a second plane is a right trapezoid, and the second plane is the plane containing two opposing edges. This structure can effectively guide the electromagnetic field distribution, suppress the excitation of higher-order modes, and reduce reflection losses caused by dielectric discontinuities. When both end faces of each rib have the same trapezoidal groove, the standing wave ratio is smaller, and it has a certain suppressive effect on higher-order modes.

[0017] Furthermore, when the dielectric support of the present invention is used in a coaxial transmission line, an angle α between the second sidewall of the groove and the end face of the body of 75° can significantly reduce the generation of higher-order modes and optimize the standing wave ratio (SWR) to below 1.03. Furthermore, with specific dimensions of the groove, and through the synergistic optimization of the maximum distance w between the first and second sidewalls, the length h of the first sidewall in the axial direction of the body, and the angle α between the second sidewall and the end face of the body, the dielectric support of the present invention can achieve an excellent SWR ≤ 1.06 in an ultra-wideband frequency range of DC to 130 GHz.

[0018] Furthermore, in the recessed portion of the dielectric support of the present invention, when the ratio of the diameter n of the semicircular segment to the length m of the first line segment is n / m=0.7, the standing wave ratio is ≤1.12 in the full frequency band range of DC~130GHz, which satisfies the signal transmission of the coaxial transmission line in a relatively wide frequency band range.

[0019] Furthermore, when the distance between the center of the semicircular segment of the recessed portion in the orthographic projection of the first plane and the center of the central through hole in the orthographic projection of the first plane is 0.35 mm, the depth of the recessed portion is moderate, which can ensure structural strength and effectively reduce the relative permittivity, thereby reducing the impact of dielectric discontinuity caused by dielectric support on microwave transmission signals. Attached Figure Description

[0020] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0021] Figure 1 This is an isometric structural diagram of a medium support according to an embodiment of the present invention; Figure 2 This is a front view schematic diagram of the medium support structure according to an embodiment of the present invention; Figure 3 yes Figure 2 AA section view; Figure 4 This is an isometric structural diagram of a transmission line (with a threaded sleeve) according to an embodiment of the present invention; Figure 5 This is a three-dimensional exploded structural diagram of a transmission line (with a threaded sleeve) according to an embodiment of the present invention; Figure 6 This is an isometric structural diagram of a transmission line (without a screw sleeve) according to an embodiment of the present invention; Figure 7 This is a front view schematic diagram of a transmission line (without a screw sleeve) according to an embodiment of the present invention; Figure 8This is a curve showing the relationship between the axial length of the medium support and the standing wave ratio according to an embodiment of the present invention; Figure 9 This is a curve showing the relationship between the size ratio n / m and the standing wave ratio of the dielectric support according to an embodiment of the present invention; Figure 10 The standing wave ratio curve of a rib having a groove on one end face according to an embodiment of the present invention; Figure 11 The standing wave ratio curve of the rib with grooves on both ends according to an embodiment of the present invention; Figure 12 This is a curve showing the relationship between the long side length of the groove portion and the standing wave ratio according to an embodiment of the present invention. Figure 13 This is a curve showing the relationship between the bevel angle of the groove portion and the standing wave ratio according to an embodiment of the present invention. Figure 14 This is a curve showing the relationship between the dimension p of the dielectric support and the standing wave ratio according to an embodiment of the present invention.

[0022] Figure label: 11. Depression; 111. Semicircular segment; 112. Straight segment; 12. Groove portion; 121. First sidewall; 122. Second sidewall; 123. Bottom wall; 13. Central through hole; 21. Outer conductor; 22. Screw sleeve; 23. Inner conductor. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0024] Example 1 Figure 1 This is an isometric structural diagram of a medium support according to an embodiment of the present invention; Figure 2 This is a front view schematic diagram of the medium support structure according to an embodiment of the present invention; Figure 3 yes Figure 2 AA section view. Combined with Figures 1-3As shown, an exemplary embodiment of the present invention provides a dielectric support for a broadband coaxial switch transmission line, comprising a body with an outer contour of a regular hexagonal prism, the body having a central through hole 13; each of the six sides of the body has a U-shaped recess 11, the recess 11 extending along the axial direction of the body and recessed toward the central axis of the body; the orthographic projection of the recess 11 onto a first plane includes a semicircular segment 111 and two opposing straight segments 112, one end of each straight segment 112 intersecting with a first line segment, and the other end being tangent to the corresponding end of the semicircular segment 111; wherein, the first plane is perpendicular to the axis. The first line segment is the orthographic projection of the side surface onto the first plane; the center of the semicircular segment 111 is on the perpendicular bisector of the first line segment; the body has a rib that separates two adjacent recesses 11, and a groove 12 is formed on the end face of the rib; the groove 12 has a first side wall 121, a bottom wall 123 and a second side wall 122 connected in sequence, the first side wall 121 is perpendicular to the bottom wall 123, and along the direction from the bottom wall 123 to the end face of the rib, the second side wall 122 extends obliquely away from the first side wall 121, and the bottom wall 123 is parallel to the first plane.

[0025] In practical applications, the medium support can be considered as forming a recess 11 by creating U-shaped grooves inward on each side of the regular hexagonal prism, thereby naturally forming ribs between adjacent recesses 11. Specifically, the recess 11 extends along the axial direction of the body to both end faces of the body, that is, the recess 11 penetrates both ends of the body. The orthographic projection of the recess 11 onto the first plane is U-shaped, that is, the cross-sectional shape of the recess 11 is U-shaped, and the first plane is a plane perpendicular to the axial direction. The orthographic projection of the recess 11 onto the first plane includes a semicircular segment 111 and two opposing straight segments 112. One end of each straight segment 112 intersects with the first line segment, and the other end is tangent to and intersects with one of the two ends of the semicircular segment 111. The first line segment refers to the orthographic projection of the side face of the regular hexagonal prism onto the first plane. It can be understood that the aforementioned first line segment refers to the orthographic projection of the corresponding side surface of the regular hexagonal prism forming the recess 11 onto the first plane.

[0026] When the recess 11 is formed on the side of the regular hexagonal prism, it can be considered as first creating a rectangular groove, then creating a semi-circular groove, with the two tangentially transitioning to form a U-shaped groove. In the same recess 11, the distance between the two straight segments 112 is the diameter of the semi-circular segment 111, and the two straight segments 112 are parallel to each other. The center of the semi-circular segment 111 is located on the perpendicular bisector of the first line segment, so that the recess 11 presents a symmetrical U-shaped structure in cross-section, which is beneficial to maintaining the uniformity of the medium support in the circumferential direction.

[0027] When the diameter of the semicircle 111 is smaller than the length of the first line segment, that is... Figure 1 As shown, ribs are naturally formed between two adjacent recesses 11, and the ribs are used to provide support points for the outer conductor 21 of the transmission line.

[0028] Combination Figure 1 and Figure 3 As shown, a groove 12 is formed on the end face of the medium-supported body to reduce the influence of higher-order modes caused by medium changes. Specifically, a groove 12 is formed on the end face of the rib. The groove 12 is approximately U-shaped. From the edge of the body to the central axis, the groove 12 has a first sidewall 121, a bottom wall 123, and a second sidewall 122 connected in sequence. The first sidewall 121 is perpendicular to the bottom wall 123. From the bottom wall 123 to the end face of the body, the second sidewall 122 extends obliquely away from the first sidewall 121. That is, in the direction away from the bottom wall 123, the distance between the second sidewall 122 and the first sidewall 121 increases, forming a funnel-shaped structure. The orthographic projection of the groove 12 onto a second plane is a right trapezoid, and the second plane is the plane containing the two opposing edges. This structure can effectively guide the electromagnetic field distribution, suppress the excitation of higher-order modes, and reduce reflection losses caused by medium discontinuities.

[0029] It should be noted that the wideband referred to in this invention is DC to 130GHz, covering a wide frequency range from low frequency to millimeter wave. Within this wideband, the dielectric-supported structure must meet the transmission performance requirements of the low-frequency band while also taking into account the impedance mismatch caused by the introduction of the dielectric in the high-frequency band, such as above 68GHz.

[0030] Furthermore, in order to solve the technical problem of the influence of higher-order modes, the present invention forms a groove 12 on both end faces of each of the six ribs of the body. The groove 12 on the two end faces of each rib is arranged in a mirror symmetry about a third plane, which is a cross-section passing through the center of the body.

[0031] Figure 10 The standing wave ratio curve of a rib having a groove on one end face according to an embodiment of the present invention; Figure 11 This refers to the standing wave ratio curve of the rib with grooved portions on both ends according to an embodiment of the present invention. (Comparison) Figure 10 and Figure 11 As shown, when one end face of each rib has a groove 12, the standing wave ratio (SWR) is ≤1.23, while when both end faces of each rib have grooves 12, the SWR is ≤1.07. Therefore, when both end faces of each rib have the same trapezoidal groove 12, the SWR is smaller, which has a certain suppressive effect on higher-order molds. This is because when this dielectric support is applied to a coaxial transmission line, due to the reciprocity of coaxial microwave transmission, using a symmetrical structure along the transmission path can achieve better microwave parameters.

[0032] Furthermore, to address the technical issues of higher-order mode influence and transmission frequency limits, the angle between the second sidewall 122 of the groove portion 12 and the end face of the main body is set to an acute angle α, such as... Figure 3 As shown, where α = 45°~75°.

[0033] Figure 13 This is a curve showing the relationship between the bevel angle and the standing wave ratio of the groove portion 12 according to an embodiment of the present invention. Figure 13 As shown, the standing wave ratio (SWR) is <1.09 when α=45°; <1.06 when α=60°; and <1.03 when α=75°. Therefore, when the dielectric support of the present invention is used in a coaxial transmission line, the generation of higher-order modes can be greatly reduced when the groove portion 12 is at α=75°, thus optimizing the SWR to below 1.03.

[0034] It should be noted that the dielectric support of the rib without the groove 12 in this invention has a theoretical upper limit of 130~145GHz. According to microwave industry theory, at the upper frequency limit, the influence of higher-order modes is greater, which will significantly deteriorate the cutoff frequency and make it difficult to improve. However, this invention, by forming grooves 12 on both end faces of the rib, allows the upper frequency limit to be increased to 150GHz while still meeting the VSWR requirements. Figure 13 As shown, this further illustrates that the acute angle α of the groove portion 12 is effective in suppressing higher-order modes.

[0035] Figure 12 This is a curve showing the relationship between the long side length of the groove portion and the standing wave ratio according to an embodiment of the present invention. Figure 3 and Figure 12 As shown, the length of the long side of the groove 12 refers to the length of the long side of the right trapezoid formed by the orthographic projection of the groove 12 on the second plane, which is also the maximum distance w between the first sidewall 121 and the second sidewall 122, which is 0.15~0.25mm. The length h of the first sidewall 121 in the axial direction of the body is 0.05mm~0.15mm.

[0036] Compared to w=0.15mm and w=0.25mm, when w=0.2mm, the standing wave ratio is approximately 1.06 (h=0.1mm, α=75°), which is better. Based on this, with the synergistic optimization of the specific dimensions w, h and α of the groove portion 12, the dielectric support of the present invention can achieve excellent performance of standing wave ratio ≤1.06 in the ultra-wide frequency band of DC~150GHz.

[0037] For example, the diameter of the central through hole 13 ranges from 0.2 mm to 0.3 mm, and the radius r2 ranges from 0.1 mm to 0.15 mm. The dielectric constant of the body material ranges from 2 to 3.6.

[0038] For example, the outer contour of the end face of the body is a regular hexagon, and the diameter of the circumcircle of the regular hexagon is in the range of 0.8mm~1.0mm, and the radius r1=0.4mm~0.5mm.

[0039] Furthermore, to address the technical challenge of maintaining support strength while satisfying the standing wave ratio, the axial length of the body is taken in the range of H, λ g / 4≤H≤λ g , where λ g The wavelength at 130 GHz is given by the equivalent dielectric constant.

[0040] Figure 8 This is a curve showing the relationship between the axial length of the dielectric support and the standing wave ratio according to an embodiment of the present invention. (Combined with...) Figure 8 and Figure 3 As shown, in the low-frequency band (0~67GHz), H=λ is generally chosen. g / 4, but for the DC~130GHz ultra-wideband covered by this invention, H=0.1mm~0.3mm, the structural strength cannot be met, therefore H is chosen to be close to λ. g For example, H=0.5mm can meet the requirements of both support strength and VSWR, and also meet the corresponding transmission performance requirements.

[0041] Furthermore, in order to address the technical problem of the standing wave ratio (VSWR) failing to maintain good performance across the entire DC~130GHz frequency band, such as... Figure 2 As shown, the ratio of the diameter n of the semicircular segment 111 to the length m of the first line segment in this invention is n / m = 0.5 to 0.7.

[0042] Figure 9 This is a curve showing the relationship between the size ratio n / m of the dielectric support and the standing wave ratio according to an embodiment of the present invention. Figure 9 As shown, when n / m=0.7, the VSWR is ≤1.12 across the entire DC~130GHz frequency band, exhibiting the best performance over such a wide frequency range. However, when n / m=0.3, the maximum VSWR across the entire frequency band approaches 1.3, which is insufficient for signal transmission on coaxial lines.

[0043] Figure 14 This is a curve showing the relationship between the dimension p of the dielectric support and the standing wave ratio according to an embodiment of the present invention. (Combined with...) Figure 2 and Figure 14 As shown, the distance p between the center of the semicircular segment 111 of the recessed portion 11 projected onto the first plane and the center of the central through hole 13 projected onto the first plane ranges from 0.25 mm to 0.4 mm.

[0044] When p = 0.25 mm, the recess 11 may intersect with the central through-hole 13, resulting in insufficient structural strength. When p = 0.4 mm, the recess 11 is too shallow, and the entire recess 11 is close to a semicircle, which cannot effectively reduce the equivalent dielectric constant. When p = 0.35 mm, the standing wave ratio is the minimum, and it does not interfere with other structures. Based on this, when p = 0.35 mm, the depth of the recess 11 is moderate, which can ensure structural strength and effectively reduce the relative dielectric constant, reduce the impact of dielectric discontinuity caused by dielectric support on microwave transmission signals, and meet the design requirements for standing wave and loss indicators in the full frequency band of DC~130 GHz.

[0045] It should be noted that the dielectric support of the present invention reduces the volume by 65% ​​to 75% compared to the annular cylindrical dielectric support with the same circumscribed circle by optimizing the outer contour of the regular hexagonal prism, as well as the size and position of the recessed portion 11 and the size and position of the groove portion 12. This reduces the equivalent dielectric constant, reduces the impact of dielectric discontinuity on high-frequency signals, and achieves the requirements of VSWR and insertion loss in the DC to 130GHz ultra-wideband, while ensuring the structural support strength and assembly reliability.

[0046] Example 2 This embodiment provides a transmission line, including the dielectric support of Embodiment 1. The transmission line is a coaxial transmission line and can operate normally in the full frequency band from DC to 130GHz.

[0047] Figure 4 This is an isometric structural diagram of a transmission line (with a threaded sleeve) according to an embodiment of the present invention; Figure 5 This is a three-dimensional exploded structural diagram of a transmission line (with a threaded sleeve) according to an embodiment of the present invention; Figure 6 This is an isometric structural diagram of a transmission line (without a screw sleeve) according to an embodiment of the present invention; Figure 7 This is a front view schematic diagram of a transmission line (without a screw sleeve) according to an embodiment of the present invention. (Combined with...) Figures 3-7 As shown, the transmission line includes an inner conductor 23, an outer conductor 21, and at least one dielectric support. The dielectric support is disposed between the inner conductor 23 and the outer conductor 21, and the six side edges of the dielectric support abut against the inner wall of the outer conductor 21. The central through hole 13 is sleeved on the inner conductor 23 to achieve coaxial positioning of the inner conductor 23 and the outer conductor 21.

[0048] A stepped surface is provided on the inner wall of the outer conductor 21 to axially limit the dielectric support. After the dielectric support is assembled with the inner conductor 23 and the outer conductor 21, it is screwed onto the outer conductor 21 by the threaded sleeve 22. The threaded sleeve 22 also has a limiting stepped surface to achieve clamping and fixing from the other side of the dielectric support, thereby making the entire transmission line structure assemblable and reliable.

[0049] It is understandable that the other end of the inner conductor 23, which is away from the dielectric support, is supported by other dielectrics to keep the inner conductor 23 and the outer conductor 21 coaxial, thereby maintaining the continuity and stability of signal transmission.

[0050] The technical advantages of the aforementioned transmission line compared to existing technologies are the same as those of the aforementioned medium support, and will not be repeated here.

[0051] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A dielectric support for a transmission line used in a broadband coaxial switch, characterized in that, Includes a body with an outer contour in the shape of a regular hexagonal prism, the body having a central through hole; The six sides of the body are each formed with a U-shaped recess, which extends along the central axis of the body and is recessed toward the central axis of the body; the orthographic projection of the recess on the first plane includes a semicircular segment and two opposing straight segments, one end of each straight segment intersecting with the first line segment.

2. The medium support according to claim 1, characterized in that, The diameter of the semicircular segment is smaller than the length of the first line segment.

3. The medium support according to claim 2, characterized in that, The outer contour of the end face of the body is a regular hexagon, and the diameter of the circumcircle of the regular hexagon ranges from 0.8 mm to 1.0 mm.

4. The medium support according to claim 2, characterized in that, The length of the body along the central axis ranges from H to λ. g / 4≤H≤λ g , where λ g The wavelength at 130 GHz is given by the equivalent dielectric constant.

5. The medium support according to claim 4, characterized in that, The dielectric constant of the material of the body is in the range of 2 to 3.

6.

6. The medium support according to claim 2, characterized in that, The diameter of the central through hole ranges from 0.2 mm to 0.3 mm.

7. The medium support according to any one of claims 1-6, characterized in that, The distance between the center of the semicircular segment of the recessed portion projected onto the first plane and the center of the central through hole projected onto the first plane ranges from 0.25mm to 0.4mm.

8. A transmission line, characterized in that, Includes the medium support as described in any one of claims 1-7, wherein the transmission line is a coaxial transmission line.

9. The transmission line according to claim 8, characterized in that, The transmission line also includes an inner conductor and an outer conductor, with the body sleeved on the inner conductor and the side edges of the body supported on the inner wall of the outer conductor.

10. The transmission line according to claim 8, characterized in that, The transmission line operates in the DC~130GHz frequency band.

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