Device for improving isolation degree of cavity and application thereof

Abstract

The invention discloses a device for improving cavity isolation and application, and the device comprises a housing and a cover plate disposed at the top of the housing, the interior of the housing is provided with a separation rib used for isolating a cavity in the housing, the device also comprises an elastic reed which is disposed at the bottom of the cover plate and clamps the separation rib, and the inner side of the housing is provided with a substrate below the separation rib. And the interior of the shell is divided into two independent cavities by the separation rib and the elastic reed. The elastic reed is designed between the separating rib and the cover plate, good contact between the separating rib and the cover plate is guaranteed through elastic deformation of the elastic reed, a large free space is provided for the allowable range of a gap between the separating rib and the cover plate, and the problem that a shielding loop is not closed due to the fact that the gap exists between the separating rib and the cover plate is solved; therefore, the isolation degree between the cavities is effectively improved. The elastic reeds have high diastolic resistance, elastic deformation can be recovered when the elastic reeds are pulled out of the separating ribs, and the problem of repeated plugging and pulling is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave transmit / receive modules (T / R modules), and in particular to a device for improving cavity isolation and application thereof. Background Art

[0002] The T / R component is the core component with the largest installed volume in active phased array radars. It contains multiple bare chips such as RF, control, and power management, which are packaged into an airtight environment through metal or ceramic packaging. The T / R component generally contains more than two amplifiers in the transmitting and receiving RF links. In order to avoid electromagnetic compatibility problems such as isolation tolerance and self-excited oscillation caused by spatial coupling and crosstalk between the front and rear amplifiers, the packaging design is generally divided into cavities, that is, the front and rear amplifiers are arranged in different cavities.

[0003] Another situation is that multi-channel T / R components usually also isolate each channel by cavity. One solution is to adopt the double-layer circuit structure proposed by Zhang Shengchun et al. in "Development of High-Isolation Millimeter-Wave Frequency-Converting Transceiver Components", that is, the microwave circuit is distributed in each cavity on the front, and its signal interconnection and power modulation are distributed on the back of the component. Although this method achieves a certain degree of cavity isolation, it invisibly increases the thickness of the component and is not suitable for the requirements of back heat dissipation of high-power T / R components.

[0004] In order to meet the requirements of T / R component integration, miniaturization, and high-power heat dissipation, the control and power supply interfaces of T / R components are generally shared by the front and rear amplifiers or multiple channels. This requires that the substrate used for signal interconnection such as control and power supply cannot be divided along with the cavity. Therefore, the specific measures for the cavity design are to bond or weld a partition rib on the substrate to form a cavity with the shell and cover of the T / R component; since the shell, substrate, partition rib, and cover have certain processing tolerances in the height direction, there must be a gap between the partition rib and the cover in the cavity. This gap will seriously affect the isolation of the two cavities.

[0005] In order to improve the isolation between the cavities, the commonly used measure in engineering is to design two raised forks on the cover plate 2' of the T / R assembly, and the partition rib 4' is embedded in the middle of the two forks. The bottom of the partition rib 4' is the substrate 3', and the substrate 3' is installed in the bottom shell 1'. Figure 1 and Figure 2As shown; due to the processing tolerances of the interdigital fingers and the partition ribs 4' on the cover plate 2' and their relative installation positions, there will also be nominal gaps l1 and l2 in the horizontal direction between the interdigital fingers and the partition ribs 4' on the cover plate 2'. The gaps l1 and l2 are generally around 0.1mm to 0.3mm. This design essentially only changes the path length of the electromagnetic wave propagation along the gap, improves the isolation at a specific frequency, but cannot meet the requirements of high isolation between broadband T / R component cavities.

[0006] Figure 3 The isolation simulation results of the structure using full-wave electromagnetic simulation software are given. In the figure, the horizontal axis represents frequency in GHz, covering from 0.01GHz to 40GHz; the vertical axis represents isolation in dB, and the middle curve represents the isolation value corresponding to each frequency point; the simulation results quantitatively confirm the above conclusions: when the gap g between the cover plate 2' and the partition 4' takes a typical value of 0.2mm and l1 and l2 are also set to the commonly used engineering dimensions of 0.2mm, there are many strong coupling frequencies in the frequency band of 0.01GHz to 40GHz, and the worst isolation is only about -5dB, while the normal engineering application requirements are generally -40dB to -35dB. The above technology is far from meeting the engineering application requirements. Summary of the invention

[0007] The technical problem to be solved by the present invention is: how to improve the isolation between different cavities of a T / R component.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] A device for improving the isolation of a cavity, comprising a shell and a cover plate installed on the top thereof, wherein the shell is provided with a partition rib for isolating the cavity in the shell, and further comprising an elastic spring installed at the bottom of the cover plate and clamping the partition rib, and a base plate is provided inside the shell and below the partition rib;

[0010] The partition ribs and the elastic spring sheet separate the interior of the shell into two independent cavities. The partition ribs, the elastic spring sheet, and the shell, the base plate and the cover plate in contact with them form a complete and continuous shielding loop.

[0011] The present application designs an elastic spring between the partition rib and the cover plate, and utilizes the elastic deformation of the elastic spring itself to ensure good contact with the partition rib, providing a larger free space for the allowable range of the gap between the partition rib and the cover plate, eliminating the problem of non-closure of the shielding circuit caused by the gap between the partition rib and the cover plate, thereby effectively improving the isolation between the cavities; the elastic spring has a high relaxation resistance, and can restore the elastic deformation when pulled out from the partition rib, solving the problem of repeated plugging and unplugging, and the elastic contact between the elastic spring and the cover plate rather than rigid crimping is conducive to the release of thermal stress caused by different thermal expansion coefficients of the shell, substrate, partition rib, cover plate, etc., and has the characteristic of high reliability.

[0012] As a further solution of the present invention: one or more rows of metallized through holes are arranged inside the substrate just below the location of the partition ribs.

[0013] As a further solution of the present invention: the elastic spring sheet includes a symmetrically distributed left part and a right part of the spring sheet, wherein the left part of the spring sheet and the right part of the spring sheet are designed as an integral whole, and the left part of the spring sheet and the right part of the spring sheet are both in an "Ω" shape, and a clamping gap for clamping the partition rib is left between the left part of the spring sheet and the right part of the spring sheet, and the horizontal sides of the left part of the spring sheet and the right part of the spring sheet are welded to the cover plate through a welding sheet assembly.

[0014] As a further solution of the present invention: the elastic spring includes a clamping portion, a bending portion and a connecting portion with an integrated design, the connecting portion is in a horizontal plane and is welded to the cover plate through a welding plate assembly, both ends of the connecting portion are simultaneously inclined toward the middle to form a clamping portion for clamping the partition ribs, and one end of the two clamping portions is simultaneously bent outwards away from the partition ribs to form a bending portion.

[0015] As a further solution of the present invention: the thickness t of the elastic spring is 0.08 mm or 0.1 mm or 0.12 mm or 0.15 mm.

[0016] As a further solution of the present invention: the initial spacing d of the elastic spring used to clamp the partition ribs is smaller than the width w of the partition ribs, and the difference between w and d is between 0.15 mm and 0.3 mm.

[0017] As a further solution of the present invention: the height h of the elastic spring is greater than the gap g between the partition rib and the cover plate, and the difference between h and g is greater than 1.5 mm.

[0018] As a further solution of the present invention: the soldering sheet is made of lead-tin or solder with a lower melting point; and the elastic spring is made of beryllium bronze material.

[0019] As a further solution of the present invention: the shell, cover plate and partition ribs are all made of metal or alloy materials.

[0020] The invention also discloses an application of the device for improving cavity isolation on a T / R component.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present application designs an elastic spring between the partition rib and the cover plate, and utilizes the elastic deformation of the elastic spring itself to ensure good contact with the partition rib, providing a larger free space for the allowable range of the gap between the partition rib and the cover plate, eliminating the problem of non-closure of the shielding circuit caused by the gap between the partition rib and the cover plate, thereby effectively improving the isolation between the cavities; the elastic spring has a high relaxation resistance, and can restore the elastic deformation when unplugged from the partition rib, solving the problem of repeated plugging and unplugging. The elastic contact between the elastic spring and the cover plate rather than the rigid crimping is conducive to the release of thermal stress caused by different thermal expansion coefficients of the shell, substrate, partition rib, cover plate, etc., and has the characteristic of high reliability. The present invention fundamentally solves the electromagnetic compatibility problems such as mutual coupling and crosstalk between cavities, and has extremely high practical significance and application value.

[0023] This application designs two elastic springs of different shapes, wherein the elastic spring can adopt a double "Ω" type structure, and the structure is modeled and the isolation simulation is performed by full-wave electromagnetic simulation software, see Figure 6 The simulation results show that: under certain parameters of g, w, d, and h, the worst isolation in the frequency range of 0.01GHz to 40GHz is below -50dB, which is better than the requirements of engineering applications. The elastic spring can also be used as Figure 8 The inverted hanger-like structure shown in the figure has a worst isolation of less than -47 dB in the frequency band of 0.01 GHz to 40 GHz under certain parameter conditions of g, w, d, and h, which can still meet the requirements of engineering applications. Therefore, the shape of the elastic spring 5 can be selected according to the actual application scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a cross-sectional view of the interdigital structure of the gap between the reinforcement and the cover plate commonly used in current projects;

[0025] Figure 2 for Figure 1 A partial enlargement of the A area and the size parameter identification diagram;

[0026] Figure 3 This is the simulation result diagram of the isolation degree of the interdigital structure of the gap between the reinforcement and the cover plate, which is commonly used in current projects;

[0027] Figure 4 It is a cross-sectional view of the partition rib and the cover plate in elastic contact with each other using double “Ω”-shaped elastic springs according to Example 1 of the present invention;

[0028] Figure 5For the present invention Figure 4 A partial enlargement of the B area and the size parameter identification diagram;

[0029] Figure 6 This is a simulation result diagram of the isolation degree of Example 1 of the present invention in which the partition rib and the cover plate adopt elastic contact with double "Ω"-shaped elastic springs;

[0030] Figure 7 A cross-sectional view of the partition rib and the cover plate of Example 2 of the present invention in elastic contact with each other using an elastic spring sheet having an inverted hanger-like structure;

[0031] Figure 8 For the present invention Figure 7 A partial enlargement of the C area and the size parameter identification diagram;

[0032] Fig. 9 This is a simulation result diagram of the isolation degree of elastic contact between the partition rib and the cover plate using an elastic spring sheet having an inverted hanger-like structure according to Example 2 of the present invention;

[0033] Description of reference numerals:

[0034] 1. Shell; 2. Cover plate; 21. Mounting groove; 3. Base plate; 4. Partition ribs;

[0035] 5. elastic spring; 511. left part of spring; 512. right part of spring; 521. clamping part; 522. bending part; 523. connecting part;

[0036] 6. Soldering piece assembly; 611. Soldering piece one; 612. Soldering piece two; 613. Soldering piece three; 621. Soldering piece four. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0038] Example 1

[0039] Reference Figure 4 and Figure 5A device for improving cavity isolation includes a shell 1, a cover plate 2, a substrate 3, a partition rib 4, an elastic spring 5 and a welding piece assembly 6. The substrate 3 is welded to the shell 1. The shell 1 is provided with a partition rib 4 located above the substrate 3 for isolating the cavity inside the shell. The cover plate 2 and the shell 1 are welded together by laser sealing or parallel sealing process to provide an airtight environment required for a bare chip; the partition rib 4 is bonded to the substrate 3 with conductive adhesive or solder; the elastic spring 5 is welded to a mounting groove 21 on one side of the cover plate 2 facing the shell 1 through the welding piece assembly 6; and the shell 1, the cover plate 2, the substrate 3, the partition rib 4 and the elastic spring 5 together separate the interior of the T / R assembly into two independent cavities.

[0040] Reference Figure 4 and Figure 5 A row of metallized through holes 31 is arranged inside the substrate 3 just below the position of the partition rib 4. To further improve the shielding effect, a row of metallized through holes 31 can be added on both sides of the left and right sides of the row of metallized through holes 31. It should be noted that the housing 1, the cover plate 2, the partition rib 4, the elastic spring 5 and the metallized through holes 31 in the substrate 3 form a complete and continuous shielding loop.

[0041] Reference Figure 4 and Figure 5 The elastic reed 5 adopts an inverted double "Ω" shape and can be stamped by a special mold.

[0042] Furthermore, the elastic spring 5 includes a symmetrically distributed left spring portion 511 and a right spring portion 512, wherein the left spring portion 511 and the right spring portion 512 are designed as an integral unit, and both the left spring portion 511 and the right spring portion 512 are in an inverted "Ω" shape, and a clamping gap is left between the left spring portion 511 and the right spring portion 512 for clamping the partition 4, and the horizontal sides of the left spring portion 511 and the right spring portion 512 are welded to the cover plate 2 through the welding plate assembly 6.

[0043] Furthermore, the thickness t of the elastic spring 5 can be selected from specifications of 0.08mm, 0.1mm, 0.12mm, and 0.15mm; it is not advisable to select thicker specifications, which will result in the elastic spring 5 and the partition rib 4 being inserted and separated with greater force and easily damaging the coating of the elastic spring 5 and the partition rib 4. The present application does not limit the thickness of the elastic spring 5, but only provides several preferred implementations for reference, rather than limiting it.

[0044] Furthermore, the elastic spring 5 is made of beryllium bronze material, and after being formed, it can be heat-treated in a hot vacuum furnace to obtain the required rigidity and elasticity.

[0045] Furthermore, the initial spacing d in the elastic spring 5 for clamping the spacer 4 is smaller than the width w of the spacer 4. In the present embodiment 1, d is the spacing between the left portion 511 of the spring and the right portion 512 of the spring, and the difference between w and d is between 0.15 mm and 0.3 mm.

[0046] Furthermore, the height h of the elastic spring 5 is greater than the gap g between the partition rib 4 and the cover plate 2, and the difference between h and g should be greater than 1.5 mm.

[0047] Reference Figure 5 In this embodiment 1, the welding piece assembly 6 is divided into welding piece 1 611, welding piece 2 612 and welding piece 3 613 according to the contact surface between the elastic spring piece 5 and the cover plate 2. Among them, the welding piece 1 611, welding piece 2 612 and welding piece 3 613 are preferably made of lead tin or solder with a lower melting point to prevent the elastic spring piece 5 from annealing and losing its elasticity due to excessively high welding temperature.

[0048] Reference Figure 4 and Figure 5 During the sealing process, the cover plate 2 with the elastic spring 5 welded thereon is buckled on the housing 1 with the elastic spring 5 facing the partition rib 4, and the partition rib 4 is inserted into the elastic spring 5. The left part 511 and the right part 512 of the elastic spring 5 are opened outward and elastically contact with the partition rib 4.

[0049] As a preferred embodiment of the present invention, the housing 1, the cover plate 2, and the ribs 4 are all made of metal or alloy materials that are good conductors and suitable for airtight packaging, such as aluminum, Kovar, titanium alloy, etc.

[0050] Reference Figure 4 In this embodiment 1, the cover plate 2, the elastic spring sheet 5, the rib 4, the metallized through hole 31 in the substrate 3 and the housing 1 form a complete and continuous shielding loop from top to bottom. The structure is modeled and the isolation is simulated by full-wave electromagnetic simulation software.

[0051] See also Figure 6 The simulation results show that when g is 0.4mm, w is 1mm, d is 0.8mm, and h is 1.9mm, the worst isolation in the 0.01GHz to 40GHz frequency range is below -50dB. Figure 6 The horizontal axis represents frequency in GHz, covering from 0.01 GHz to 40 GHz; the vertical axis represents isolation in dB, and the middle curve represents the isolation value corresponding to each frequency point. For example, the worst m1 identification point indicates that the cavity isolation value at 23.0042 GHz is -50.9648 dB; normal engineering application requirements are generally between -40 dB and -35 dB, and this embodiment 1 is already better than the engineering application requirements.

[0052] Example 2

[0053] Reference Figure 7 and Figure 8 The other aspects of the present embodiment 2 are the same as those of the embodiment 1, except for the shape of the elastic spring 5 and the number of welding areas with the cover plate 2.

[0054] Furthermore, the elastic spring 5 includes an integrally designed clamping portion 521, a bending portion 522 and a connecting portion 523. The connecting portion 523 is in a horizontal plane and is welded to the cover plate 2 through a welding piece 621. Both ends of the connecting portion 523 are simultaneously inclined toward the middle to form a clamping portion 521 for clamping the partition 4. One end of the two clamping portions 521 is simultaneously bent outwardly away from the partition 4 to form a bending portion 522. Only one welding is required between the elastic spring 5 and the cover plate 2 in this embodiment. Since the left arm and the right arm of the elastic spring 5 are in a free state, that is, the two bending portions 522, the force of the elastic spring 5 and the partition 4 to be inserted and separated is slightly smaller than that in embodiment 1.

[0055] See also Fig. 9 The structure was modeled and the isolation was simulated by full-wave electromagnetic simulation software, using the same parameters as in Example 1, i.e., g was 0.4 mm, w was 1 mm, d was 0.8 mm, and h was 1.9 mm. The simulation results showed that the worst isolation in the frequency range of 0.01 GHz to 40 GHz was below -47 dB. Fig. 9 The middle horizontal axis represents the frequency, in GHz, covering from 0.01GHz to 40GHz; the vertical axis represents the isolation, in dB, and the middle curve represents the isolation value corresponding to each frequency point. For example, the worst m1 mark point indicates that the cavity isolation value at 36.4009GHz is -47.4489dB, which is slightly worse than that of Example 1 by 3dB, but can still meet the engineering application requirements. The shape of the elastic reed 5 of Example 1 or Example 2 can be selected according to the actual application scenario.

[0056] Example 3

[0057] This embodiment 3 provides a T / R component, which adopts the structure of embodiment 1 or embodiment 2 to improve the cavity isolation.

[0058] The present invention designs an elastic spring 5 between the partition rib 4 and the cover plate 2, and utilizes the elastic deformation of the elastic spring 5 itself to ensure good contact with the partition rib 4, which can not only avoid putting forward stringent requirements on the design of the gap between the partition rib 4 and the cover plate 2, but also eliminate the problem of non-closure of the shielding circuit caused by the existence of the gap, thereby greatly improving the isolation between the cavities; the elastic spring 5 has a high relaxation resistance, and can restore the elastic deformation when unplugged from the partition rib 4, so as to adapt to the actual application of repeated plugging and unplugging; the elastic contact between the elastic spring 5 and the cover plate 2 rather than the rigid crimping is conducive to the release of thermal stress caused by different thermal expansion coefficients of the shell 1, the substrate 3, the partition rib 4, the cover plate 2, etc., and has the characteristic of high reliability.

[0059] From the simulation results of the full-wave electromagnetic simulation software in the two embodiments, it can be seen that there are excellent isolation indicators in the frequency range of 0.01GHz to 40GHz, which is suitable for the application scenarios where the pre- and post-amplifier cavity of broadband T / R components or multi-channel cavity has a high cavity isolation requirement. The present invention fundamentally solves the electromagnetic compatibility problems such as mutual coupling and crosstalk between cavities, and has extremely high practical significance and application value.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for improving cavity isolation, comprising a housing (1) and a cover plate (2) mounted on the top thereof, wherein the housing (1) is provided with a partition rib (4) for isolating the cavity inside the housing, characterized in that: It also includes an elastic spring sheet (5) installed at the bottom of the cover plate (2) and clamping the partition rib (4); a base plate (3) is arranged inside the housing (1) and below the partition rib (4); The partition ribs (4) and the elastic spring sheet (5) separate the interior of the housing (1) into two independent cavities; the partition ribs (4), the elastic spring sheet (5) and the housing (1), the base plate (3) and the cover plate (2) in contact therewith form a complete and continuous shielding loop.

2. The device for improving cavity isolation according to claim 1, characterized in that: One or more rows of metallized through holes (31) are arranged inside the substrate (3) just below the location of the partition ribs (4).

3. The device for improving cavity isolation according to claim 1, characterized in that: The elastic spring sheet (5) comprises a symmetrically distributed left spring sheet portion (511) and a right spring sheet portion (512), wherein the left spring sheet portion (511) and the right spring sheet portion (512) are designed as an integral unit, and both the left spring sheet portion (511) and the right spring sheet portion (512) are in an "Ω" shape, and a clamping gap for clamping a spacer rib (4) is left between the left spring sheet portion (511) and the right spring sheet portion (512), and the horizontal surfaces of the left spring sheet portion (511) and the right spring sheet portion (512) are welded to the cover plate (2) via a welding sheet assembly (6).

4. The device for improving cavity isolation according to claim 1, characterized in that: The elastic spring sheet (5) comprises a clamping portion (521), a bending portion (522) and a connecting portion (523) of an integrated design; the connecting portion (523) is in a horizontal plane and is welded to the cover plate (2) via a welding sheet assembly (6); both ends of the connecting portion (523) are simultaneously inclined toward the middle to form a clamping portion (521) for clamping the partition rib (4); and one end of the two clamping portions (521) is simultaneously bent outwardly away from the partition rib (4) to form a bending portion (522).

5. A device for improving cavity isolation according to claim 3 or 4, characterized in that: The thickness t of the elastic spring (5) is 0.08 mm, 0.1 mm, 0.12 mm or 0.15 mm.

6. A device for improving cavity isolation according to claim 3 or 4, characterized in that: The initial spacing d of the elastic spring sheet (5) used to clamp the partition rib (4) is smaller than the width w of the partition rib (4), and the difference between w and d is between 0.15 mm and 0.3 mm.

7. A device for improving cavity isolation according to claim 3 or 4, characterized in that: The height h of the elastic spring sheet (5) is greater than the gap g between the partition rib (4) and the cover plate (2), and the difference between h and g is greater than 1.5 mm.

8. The device for improving cavity isolation according to claim 1, characterized in that: The welding sheet (6) is made of lead tin or solder with a lower melting point; and the elastic spring (5) is made of beryllium bronze material.

9. The device for improving cavity isolation according to claim 1, characterized in that: The shell (1), cover plate (2) and partition ribs (4) are all made of metal or alloy materials.

10. Application of the device for improving cavity isolation as described in any one of claims 1 to 9 in a T / R assembly.

Images