CN217544895U - Improved microstrip line coaxial conversion structure suitable for millimeter wave Q wave band - Google Patents

Abstract

The utility model relates to a waveguide coaxial transition equipment technical field especially relates to an improvement type microstrip line coaxial transition structure who is fit for millimeter wave Q wave band, include: the module comprises a module shell, wherein a radio frequency insulator mounting hole is formed in the module shell; the microstrip line is arranged on the module shell; radio frequency insulator, radio frequency insulator set up in module housing's mounting hole, and radio frequency insulator includes: the inner conductor penetrates through the columnar body along the axial direction of the columnar body, and the inner conductor extends outwards along the two axial ends of the columnar body respectively; one end of the inner conductor is connected with the microstrip line through the gold belt ring, one end of the inner conductor is fixedly connected with the inner wall of the gold belt ring, and the microstrip line is fixedly connected with the outer wall of the gold belt ring. The utility model discloses a coaxial conversion structure can improve the performance of whole system, avoids the connection between microstrip line and the insulator to produce the problem of fracture owing to different material thermal expansion coefficient's difference when operating temperature sharply becomes simultaneously.

Description

Improved microstrip line coaxial conversion structure suitable for millimeter wave Q wave band

Technical Field

The utility model relates to a waveguide coaxial transition equipment technical field especially relates to an improvement type microstrip line coaxial transition structure who is fit for millimeter wave Q wave band.

Background

The microstrip line is a microwave transmission line composed of a single conductor strip supported on a dielectric substrate, and has the characteristics of small volume, light weight, wide use frequency band, high reliability, low manufacturing cost and the like. Since the early 60 s, microwave integrated circuits were formed due to the development of microwave low-loss dielectric materials and microwave semiconductor devices, so that planar-structure microstrip transmission lines suitable for manufacturing microwave integrated circuits were widely used. Products of planar microstrip line construction need to be connected to coaxial lines of the same characteristic impedance during testing and use, usually in modular form with input and output coaxial connectors, as shown in fig. 1. Because the width of the two is greatly different, the two are discontinuous at the joint, and relatively large reflection is generated, thereby affecting the performance of the product.

The microstrip line and the coaxial line are two common transmission lines in a microwave system, the two transmission lines are directly welded in a common interconnection mode at a low frequency band, the coaxial inner conductor is welded on a metal strip line of the microstrip line, and the outer conductor is arranged on a ground plane of the microstrip line, as shown in fig. 2, the connection mode has little influence on the transmission of microwave signals in the low frequency band, but in a millimeter wave frequency band, the connection mode can cause the increase of the loss of millimeter wave signals. In addition, the hard connection mode of direct welding is easy to generate connection crack under the use environment with large temperature change to cause system performance collapse.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is: the technical problems that in the prior art, a microstrip line and a coaxial inner conductor are hard welded, in a millimeter wave frequency band, the loss of millimeter wave signals is increased due to the connection mode, and the system is broken due to the fact that connection cracks are easily generated when the microstrip line and the coaxial inner conductor are used in a high-temperature environment are solved. The utility model provides an improvement type microstrip line coaxial transformation structure who is fit for millimeter wave Q wave band effectively reduces standing-wave ratio and insertion loss at the within range of Q wave band, improves the performance of whole system, avoids the connection between microstrip line and the insulator to produce the fracture owing to different material thermal expansion coefficient's difference when operating temperature sharply changes simultaneously. The utility model provides a technical scheme that its technical problem adopted is: an improved microstrip coaxial transition structure suitable for a millimeter wave Q band, comprising:

the module comprises a module shell, a module body and a module body, wherein a radio frequency insulator mounting hole is formed in the module shell;

a microstrip line disposed on the module housing;

a radio frequency insulator disposed in the mounting hole of the module housing, the radio frequency insulator including: the inner conductor penetrates through the columnar body along the axial direction of the columnar body, and two ends of the inner conductor along the axial direction of the columnar body extend outwards respectively;

one end of the inner conductor is connected with the microstrip line through the gold strap ring, one end of the inner conductor is fixedly connected with the inner wall of the gold strap ring, and the microstrip line is fixedly connected with the outer wall of the gold strap ring.

The utility model discloses a gold strap ring replaces traditional direct welding, jin Daihuan's inner wall and inner conductor's outer wall fixed connection, the bottom outer wall and the microstrip line fixed connection of gold strap ring, such connected mode has both kept original electric connectivity through the biggest similarity on the physical connection, this point has been verified through the radio frequency performance electromagnetic simulation comparison to the same transmission line structure that contains direct welding and gold strap and connect, on the other hand, because the flexible extension characteristic of gold strap ring, the soft gold strap ring of connecting microstrip line and coaxial inner conductor has formed a flexible connection, allow the relative motion of certain degree that causes because different thermal expansions between microstrip line and coaxial inner conductor, and unlikely signal connection fails.

Furthermore, in order to optimize and improve the connection performance, the mounting hole comprises a first mounting hole, a second mounting hole and a compensation hole arranged between the first mounting hole and the second mounting hole, the columnar body of the radio-frequency insulator is arranged in the first mounting hole, one end of the inner conductor is divided into a front section, a middle section and a rear section, the front section is fixedly connected with a metal belt ring, the rear section is connected with the columnar body, the middle section of the inner conductor is arranged in the second mounting hole, and the rear section of the inner conductor is arranged in the compensation hole.

Further, in order to improve the insertion loss, the microstrip line comprises a body section and a connecting section which are connected with each other, the width of the connecting section is smaller than that of the body section, and the connecting section is fixedly connected with the outer wall of the Jin Daihuan.

Furthermore, the diameter of the first mounting hole is 1.98mm, the diameter of the compensation hole is 1.14mm, the distance from front to back is taken as the depth, the depth of the compensation hole is 0.4mm, the diameter of the second mounting hole is 0.7mm, and the depth of the second mounting hole is 1.4mm.

Further, in order to facilitate welding, the overlapped part of the microstrip line and the Jin Daihuan is fixed by spot welding through a metal contact type press welder.

Furthermore, the periphery of the cylindrical main body of the radio frequency insulator is mechanically and electrically connected with the first mounting hole through conductive adhesive.

Furthermore, the circumferential length of Jin Daihuan is 4-5 times of the diameter of the inner conductor, so that the diameter of the formed gold strap ring is slightly larger than the diameter of the inner conductor, the contact area between the gold strap ring and the inner conductor is effectively increased, and good connection is formed between the gold strap ring and the inner conductor.

Further, the microstrip line is arranged on the module shell through the microstrip substrate.

The utility model has the advantages that the improved microstrip line coaxial conversion structure suitable for the millimeter wave Q wave band can effectively reduce the standing-wave ratio and the insertion loss of the connection between the microstrip and the coaxial line in a range extending to the higher millimeter wave frequency, and improve the performance of the whole system; meanwhile, the condition that the connection fails due to crack caused by the difference of thermal expansion coefficients of different materials when the working temperature is changed sharply in a direct welding mode between the microstrip line and the coaxial inner conductor is avoided, and a stable, reliable and excellent microstrip-coaxial connection mode selection is provided for wide-area engineering application from common use to extreme environment with high requirements.

Drawings

The present invention will be further described with reference to the accompanying drawings and examples.

FIG. 1 is a diagram of a typical microwave product with coaxial connectors and consisting of a planar microstrip circuit;

FIG. 2 is a schematic diagram of the direct welding of an inner conductor and a microstrip line of a radio frequency insulator in the prior art;

fig. 3 is a schematic view of the coaxial conversion structure of the improved microstrip line suitable for the millimeter wave Q band of the utility model;

FIG. 4 is a comparison graph of the radio frequency performance electromagnetic simulation of the present invention using gold strap connection and the prior art using direct welding;

fig. 5 is a schematic structural view of the present invention with a coaxial compensation hole;

fig. 6 is a comparison graph of reflection loss simulation results of the present invention with and without the coaxial compensation hole;

fig. 7 is a schematic diagram of the microstrip line and gold strip of the present invention;

fig. 8 is a graph comparing simulation results of insertion loss between a narrowed microstrip line connection end and an unshown microstrip line connection end according to the present invention.

In the figure:

the prior art is as follows: 10', a module housing; 20', a microstrip line; 30', a radio frequency insulator; 32', an inner conductor; 50', a microstrip substrate;

the utility model discloses: 10. a module housing; 11. a first mounting hole; 12. a compensation hole; 13. a second mounting hole; 20. a microstrip line; 21. a body section; 22. a connecting section; 30. a radio frequency insulator; 31. a columnar body; 32. an inner conductor; 40. jin Daihuan; 50. a microstrip substrate; A. and (7) welding points.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic drawings and illustrate the basic structure of the present invention only in a schematic manner, and thus show only the components related to the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description of the present invention and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may include, for example, a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood as a specific case by those skilled in the art.

As shown in fig. 3, an improved microstrip coaxial transformation structure suitable for the millimeter wave Q band includes: module casing 10, microstrip line 20 and radio frequency insulator 30 are provided with the radio frequency insulator 30 mounting hole on the module casing 10, and microstrip line 20 sets up on module casing 10, and radio frequency insulator 30 sets up in the mounting hole of module casing 10, and radio frequency insulator 30 includes: the inner conductor 32 penetrates through the cylindrical body 31 along the axial direction of the cylindrical body 31, and two ends of the inner conductor 32 along the axial direction of the cylindrical body 31 extend outwards respectively;

one end of the inner conductor 32 is connected with the microstrip line 20 through the gold belt ring 40, one end of the inner conductor 32 is fixedly connected with the inner wall of the gold belt ring 40, and the microstrip line 20 is fixedly connected with the outer wall of the gold belt ring 40.

The utility model discloses a gold belt ring 40 replaces traditional direct welding, the inner wall of gold belt ring 40 and inner conductor 32's outer wall fixed connection, gold belt ring 40's bottom outer wall and microstrip line 20 fixed connection, such connected mode has both kept original electric connectivity through the biggest similarity on the physical connection, this point has been verified through the radio frequency performance electromagnetic simulation comparison to the same transmission line structure that contains direct welding and gold belt connection, as shown in fig. 4, on the other hand, because the flexible extending characteristic of gold belt ring 40, the soft gold belt ring 40 of connecting microstrip line 20 and coaxial inner conductor 32 has formed a flexible connection, allow microstrip line 20 and coaxial inner conductor 32 within a definite time because the relative motion of the certain degree that different thermal expansions caused, and unlikely signal connection fails.

In the prior art, the microstrip line 20 'and the inner conductor 32' are directly welded, as shown in fig. 2, the welding point is a, such a hard link has a hidden trouble, when the environmental temperature changes greatly, the difference in thermal expansion performance between the microstrip substrate 50 'material and the module housing 10' connected with the radio frequency insulator 30 'will generate a separate stress on the hard link, and when the stress is large to a certain extent, the welding point will be cracked, so that the signal connection from the microstrip line 20' to the coaxial line becomes weak, unstable, or even fails completely.

The mounting hole includes first mounting hole 11, second mounting hole 13 and the compensation hole 12 of setting between first mounting hole 11 and second mounting hole 13, the column body 31 of radio frequency insulator 30 sets up in first mounting hole 11, the one end of inner conductor 32 is divided into the anterior segment, interlude and back end, anterior segment fixed connection golden belt ring 40, back end and column body 31 are connected, the interlude setting of inner conductor 32 is in second mounting hole 13, the back end setting of inner conductor 32 is in compensation hole 12.

Because of the difference in the filler material, the cylindrical body 31 and the inner conductor 32, both 50 ohms, have a large drop in diameter, and therefore, directly abutting them creates a discontinuity in physical dimensions that affects electrical performance. As shown in fig. 5, a coaxial compensation hole 12 is added between the first mounting hole 11 and the second mounting hole 13, and the length and the outer diameter of the coaxial segment of the compensation hole 12 are adjusted by simulation, so as to obtain optimized and improved connection performance.

As shown in fig. 6, it can be seen that the addition of the coaxial compensation hole 12 provides a significant improvement in the electrical performance at the high end of the millimeter wave band.

As shown in fig. 3, the microstrip line 20 includes a body section 21 and a connection section 22 connected to each other, the width of the connection section 22 is smaller than the width of the body section 21, and the connection section 22 is fixedly connected to the outer wall of the gold band ring 40.

Consider the physics discontinuity of the relative microstrip line 20 of golden belt ring 40 structure, it presents a little higher impedance at the high-band, the utility model discloses reduced microstrip line 20's width at golden belt ring 40 junction area, improved the impedance matching performance of whole microstrip-coaxial transform through the microstrip line 20 changeover portion high impedance that narrows.

As shown in fig. 8, it is known from electromagnetic simulation that the width of the connection portion with the gold strap ring 40 is reduced, so that the transmission characteristic of the whole microstrip coaxial conversion can be effectively improved, and particularly, in a higher millimeter wave frequency band such as a Q band, the insertion loss can be improved by nearly one time.

As shown in fig. 5, the diameter of the first mounting hole 11 is 1.98mm, the diameter of the compensation hole 12 is 1.14mm, the distance from the front to the rear is defined as the depth, the depth of the compensation hole 12 is 0.4mm, the diameter of the second mounting hole 13 is 0.7mm, and the depth of the second mounting hole 13 is 1.4mm.

For the convenience of soldering, the overlapping portion of the microstrip line 20 and the gold band ring 40 is fixed by spot welding with a metal contact type press welder.

The periphery of the columnar main body of the radio frequency insulator 30 and the first mounting hole 11 are mechanically and electrically connected through conductive adhesive.

The circumferential length of the gold strap ring 40 is 4-5 times of the diameter of the inner conductor 32, so that the diameter of the formed gold strap ring 40 is slightly larger than that of the inner conductor 32, the contact area of the gold strap ring 40 and the inner conductor 32 is effectively increased, and good connection is formed between the gold strap ring 40 and the inner conductor 32.

The microstrip line 20 is disposed on the module case 10 through the microstrip substrate 50.

The method comprises the following specific implementation steps:

s1, optimizing by using electromagnetic simulation software to obtain the size of the coaxial compensation hole 12: the diameter is 1.14mm, and the depth is 0.4mm;

s2, milling three sections of concentric holes with different diameters for installing the radio frequency insulator 30 at corresponding positions on the module shell 10: the diameter of the first mounting hole 11 is 1.98mm, and the first mounting hole is used for mounting a columnar main body of the radio frequency insulator 30, the diameter of the compensation hole 12 is 1.14mm, the depth of the compensation hole is 0.4mm, and the diameter of a 50 ohm air coaxial line outer conductor hole of the second mounting hole 13, which is calculated according to the diameter of an inner conductor 32 of the radio frequency insulator 30, is 0.7mm, the depth of the second mounting hole is 1.4mm, but the performance is not influenced by slight adjustment according to actual needs;

s3, preparing a microstrip substrate 50, wherein one example is a 0.127mm thick ceramic substrate with a dielectric constant of 9.4, the width of the 50-ohm microstrip line 20 is 0.127mm, the length of the narrow section is 0.4mm, and the width of the narrow section is 0.04 mm;

s4, preparing the gold strip at the 20-end of the microstrip line: a section of gold belt with the width of 0.127mm and the length of about 1.5mm is taken and symmetrically arranged at the position of a slightly eccentric endpoint of the upper center of the high-resistance section of the microstrip line 20, and the overlapping part of the gold belt and the microstrip is firmly welded by a metal contact type press welder;

s5, installing the radio frequency insulator 30 into the installation hole by using conductive adhesive, as shown in figure 5, ensuring that the insulator is positioned in the center of the hole and the main body is tightly attached to the first installation hole 11, and achieving good mechanical and electrical connection on the periphery of the columnar main body through the conductive adhesive and the first installation hole 11;

s6, the radio frequency insulator 30 is characterized in that the length of the front section of the inner conductor 32 of the radio frequency insulator 30 above the gold band at the end of the microstrip is about 0.3mm (slightly longer than the width of the gold band by 0.127 mm), and the length of the gold band is about 1.5mm (4-5 times of the diameter of the inner conductor 32 of the insulator, which is 0.3 mm), as shown in FIG. 7.

S7, wrapping the two ends of the gold band upwards along the insulator inner conductor 32 to form a gold band ring 40 (the diameter is about 1.5 times of the diameter of the insulator inner conductor 32 needle) slightly larger than the insulator inner conductor 32, overlapping the two ends of the gold band above the insulator inner conductor 32, and fixing the overlapped gold band above the insulator inner conductor 32 by using an electric welding machine or conductive adhesive until the gold band ring 40 is installed.

The improved microstrip line coaxial conversion structure suitable for the millimeter wave Q wave band can effectively reduce the standing-wave ratio and the insertion loss of connection between the microstrip and the coaxial line in a range extending to a higher millimeter wave frequency, and improve the performance of the whole system, as shown in fig. 4, 6 and 8;

meanwhile, the condition that the connection fails due to crack caused by the difference of thermal expansion coefficients of different materials when the working temperature is changed sharply in a direct welding mode between the microstrip line 20 and the coaxial is avoided, and a stable, reliable and excellent microstrip-coaxial connection mode is provided for wide area engineering application from common use to extreme environment with high requirements.

In light of the foregoing, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined by the scope of the claims.

Claims (8)

1. The utility model provides an improvement type microstrip line coaxial transformation structure who is fit for millimeter wave Q wave band which characterized in that includes:

the module comprises a module shell (10), wherein a radio frequency insulator (30) mounting hole is formed in the module shell (10);

a microstrip line (20), the microstrip line (20) being disposed on the module housing (10);

radio frequency insulator (30), radio frequency insulator (30) set up in the mounting hole of module casing (10), radio frequency insulator (30) include: the cable comprises a cylindrical body (31) and an inner conductor (32) arranged in the cylindrical body (31), wherein the inner conductor (32) axially penetrates through the cylindrical body (31) along the cylindrical body (31), and two ends of the inner conductor (32) in the axial direction of the cylindrical body (31) respectively extend outwards;

one end of the inner conductor (32) is connected with the microstrip line (20) through Jin Daihuan (40), one end of the inner conductor (32) is fixedly connected with the inner wall of the gold band ring (40), and the microstrip line (20) is fixedly connected with the outer wall of the gold band ring (40).

2. The improved microstrip line coaxial transformation structure suitable for the millimeter wave Q band according to claim 1, wherein the mounting holes include a first mounting hole (11), a second mounting hole (13), and a compensation hole (12) disposed between the first mounting hole (11) and the second mounting hole (13), the cylindrical body (31) of the radio frequency insulator (30) is disposed in the first mounting hole (11), one end of the inner conductor (32) is divided into a front section, a middle section, and a rear section, the front section is fixedly connected to Jin Daihuan (40), the rear section is connected to the cylindrical body (31), the middle section of the inner conductor (32) is disposed in the second mounting hole (13), and the rear section of the inner conductor (32) is disposed in the compensation hole (12).

3. The improved microstrip coaxial transformation structure suitable for the millimeter wave Q band according to claim 2, wherein the microstrip (20) includes a body section (21) and a connection section (22) connected to each other, the width of the connection section (22) is smaller than the width of the body section (21), and the connection section (22) is fixedly connected to the outer wall of Jin Daihuan (40).

4. The modified microstrip coaxial conversion structure according to claim 2, wherein the diameter of the first mounting hole (11) is 1.98mm, the diameter of the compensation hole (12) is 1.14mm, the distance from front to back is defined as depth, the depth of the compensation hole (12) is 0.4mm, the diameter of the second mounting hole (13) is 0.7mm, and the depth of the second mounting hole (13) is 1.4mm.

5. The improved microstrip line coaxial transformation structure suitable for the millimeter wave Q band according to claim 3, characterized in that the overlapping portion of the microstrip line (20) and the Jin Daihuan (40) is fixed by spot welding through a metal contact bonding machine.

6. The improved microstrip coaxial transition structure suitable for the millimeter wave Q band according to claim 3, wherein the periphery of the columnar main body of the radio frequency insulator (30) and the first mounting hole (11) are mechanically and electrically connected through a conductive adhesive.

7. The improved microstrip coaxial transition structure suitable for the millimeter wave Q band according to claim 3, wherein the circumferential length of Jin Daihuan (40) is 4-5 times the diameter of the inner conductor (32).

8. The improved microstrip line coaxial transformation structure suitable for the millimeter wave Q-band according to claim 1, wherein the microstrip line (20) is disposed on the module housing (10) through a microstrip substrate (50).

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