Suspended line filter

Abstract

The utility model relates to the technical field of radio frequency microwave circuits, in particular to a suspended line filter. According to the suspended line filter provided by the utility model, the circuit board technology is utilized, the five layers of substrates formed by pressing are arranged, the first preset area of the second substrate is set as the first hollow structure, and the second preset area of the fourth substrate is set as the second hollow structure, so that the inner layers of the five layers of substrates form a cavity; according to the suspended line filter, the first substrate is arranged in the cavity, and the filter transmission line is arranged on the third substrate in the cavity, so that the production cost of the suspended line filter is greatly reduced, the suspended line filter has the characteristics of low loss, miniaturization, high integration and reliable structure, and the substrates are laminated into a whole through lamination without additional assembly, so that the volume production of products is facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of radio frequency microwave circuits, in particular to a suspended line filter. Background Art

[0002] Suspended line high-pass filter is a type of filter design used in RF and microwave frequency ranges, mainly used to pass high-frequency signals and suppress low-frequency signals. This filter adopts the transmission line theory, and its core structure usually includes one or more suspended transmission lines, such as microstrip lines, strip lines, coaxial lines or waveguides. It is widely used in wireless communications, radar, satellite communications, electronic countermeasures, instrumentation and many other fields.

[0003] In the prior art, the suspended line high-pass filter manufacturing process needs to be packaged in a machined metal box and assembled using positioning holes, positioning pins, bolts, nuts and other auxiliary mechanical parts. Manual assembly and welding operations are required, which increases the production cost of the suspended line high-pass filter and makes it impossible to implement large-scale mass production. Utility Model Content

[0004] The embodiment of the utility model provides a suspended line filter to solve the problem that the suspended line high-pass filter in the prior art is high in cost and cannot be mass-produced.

[0005] In a first aspect, the utility model provides a suspended line filter, which includes at least a first substrate, a second substrate, a third substrate, a fourth substrate and a fifth substrate that are pressed together, a first preset area of ​​the second substrate is set as a first hollow structure, a second preset area of ​​the fourth substrate is set as a second hollow structure, and a filter transmission line is set at the copper layer of the circuit area of ​​the third substrate.

[0006] In one embodiment, a first air hole is disposed on the first substrate, and the first air hole is connected to the first hollow structure.

[0007] In one embodiment, second ventilation holes are provided on the third substrate, and the second ventilation holes are respectively connected to the first hollow structure and the third hollow structure.

[0008] In one embodiment, a third ventilation hole is disposed on the fifth substrate, and the third ventilation hole is communicated with the second hollow structure.

[0009] In one embodiment, an opening position of the first ventilation hole is opposite to an opening position of the second ventilation hole.

[0010] In one embodiment, electromagnetic shielding metal layers are respectively disposed on surfaces of the first substrate and the fifth substrate.

[0011] In one embodiment, an adhesive layer is disposed between each of the upper and lower adjacent substrates, and the adhesive layer is a prepreg.

[0012] In one embodiment, the areas of the first preset area and the second preset area are both larger than the circuit area.

[0013] In one embodiment, the suspended line filter further includes a first via hole penetrating through each of the substrates, an output pad is provided on the first substrate or the fifth substrate, and one end of the first via hole is connected to the output pad.

[0014] In one embodiment, the suspended line filter further includes a second via hole penetrating through each of the substrates, a ground pad is provided on the first substrate or the fifth substrate, and one end of the second via hole is connected to the ground pad.

[0015] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0016] The utility model discloses a suspension line filter which utilizes a circuit board process to set a five-layer substrate formed by pressing together, wherein a first preset area of ​​the second substrate is set as a first hollow structure, and a second preset area of ​​the fourth substrate is set as a second hollow structure, so that the inner layer of the five-layer substrate forms a cavity, and a filter transmission line is set on the third substrate inside the cavity, thereby greatly reducing the production cost of the suspension line filter, and having the characteristics of low loss, miniaturization, strong integration and reliable structure, and utilizing lamination to press the various substrates together into a whole, without the need for additional assembly, thereby facilitating mass production of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments of the utility model will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a side view structural diagram of a suspended line filter provided by an embodiment of the utility model;

[0019] Figure 2 It is a side view structural diagram of a suspended line filter provided by an embodiment of the utility model;

[0020] Figure 3 It is a side view structural diagram of a suspended line filter provided by an embodiment of the utility model;

[0021] Figure 4It is a side view structural diagram of a suspended line filter provided by an embodiment of the utility model;

[0022] Figure 5 It is a side view structural diagram of a suspended line filter provided by an embodiment of the utility model;

[0023] Figure 6 It is a side view structural diagram of a suspended line filter provided by an embodiment of the utility model;

[0024] Figure 7 It is a side view structural diagram of a suspended line filter provided by an embodiment of the utility model;

[0025] Figure 8 It is a side view structural diagram of a suspended line filter provided by an embodiment of the utility model;

[0026] Among them, 1. first substrate, 2. second substrate, 3. third substrate, 4. fourth substrate, 5. fifth substrate, 6. electromagnetic shielding metal layer, 7. adhesive layer, 11. first air hole, 21. first preset area, 31. line area, 32. filter transmission line, 33. second air hole, 41. second preset area, 51. third air hole, 81. first via hole, 82. output pad, 91. second via hole, 92. ground pad. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0028] In the description of the present invention, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In order to thoroughly understand the present invention, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0031] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs. It will be further understood that the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0032] In one embodiment, if Figure 1 As shown, a side view structural schematic diagram of a suspended line filter is provided, including: the suspended line filter includes at least a first substrate 1, a second substrate 2, a third substrate 3, a fourth substrate 4 and a fifth substrate 5 which are pressed together, the first preset area 21 of the second substrate 2 is set as a first hollow structure, the second preset area 41 of the fourth substrate 4 is set as a second hollow structure, and a filter transmission line 32 is set at the copper layer of the line area 31 of the third substrate 3.

[0033] Specifically, the substrates and the semi-cured sheets can be stacked alternately and pressed together under high temperature and high pressure conditions using a pressing machine to obtain a pressed five-layer substrate. Preferably, a solder pad can be set on the upper surface of the topmost substrate or the lower surface of the bottommost substrate of the five-layer substrate, so that the suspended line filter can be connected to the outside through the solder pad.

[0034] It is understandable that the Figure 1The suspended line filter shown is composed of five substrates, namely a first substrate 1, a second substrate 2, a third substrate 3, a fourth substrate 4 and a fifth substrate 5. As other implementations, the suspended line filter of this embodiment can also be composed of six substrates. The suspended line filter of this embodiment can also be composed of seven substrates. The suspended line filter of this embodiment can be composed of any integer number of layers greater than four. The first preset area 21 and the second preset area 41 can be symmetrically arranged relative to the third substrate 3. The first preset area 21 and the second preset area 41 can also be asymmetrically arranged relative to the third substrate 3. Preferably, the first preset area 21 and the second preset area 41 are symmetrically arranged.

[0035] The third substrate 3 is provided with a filter transmission line 32. Specifically, the filter transmission line 32 can be provided only on the upper surface of the third substrate 3, the filter transmission line 32 can also be provided only on the lower surface of the third substrate 3, or the filter transmission line 32 can also be provided on the upper surface and the lower surface of the third substrate 3. Preferably, as Figure 1 As shown, the filter transmission line 32 is arranged on the upper and lower surfaces of the third substrate 3, avoiding the problem of insufficient power feeding caused by a single-sided circuit.

[0036] The suspended line filter of the present embodiment utilizes the circuit board process to set a five-layer substrate formed by pressing together, and the first preset area of ​​the second substrate 2 is set as the first hollow structure, and the second preset area of ​​the fourth substrate 4 is set as the second hollow structure, so that the inner layer of the five-layer substrate forms a cavity, and a filter transmission line 32 is arranged on the third substrate 3 inside the cavity, which greatly reduces the production cost of the suspended line filter, has the characteristics of low loss, miniaturization, strong integration, and reliable structure, and utilizes lamination to press the various substrates into a whole, without the need for additional assembly, and is convenient for mass production of products.

[0037] In one embodiment, if Figure 2 As shown, a side view structural diagram of a suspended line filter is provided. Figure 1 On the basis of the suspended line filter shown, a first air hole 11 is provided on the first substrate 1, and the first air hole 11 is connected to the first hollow structure.

[0038] The first air hole 11 can be set in any area on the first substrate 1 that can be connected to the first hollow structure. It can be understood that the first air hole 11 is used to allow the cavity formed by the first substrate 1, the second substrate 2 and the third substrate 3 to be ventilated when the five-layer substrate is pressed together. Therefore, the first air hole 11 only needs to be a through hole on the first substrate 1. The first air hole 11 can be metallized or not. The size of the first air hole 11 can be set according to the actual application situation, so that the first air hole 11 can be ventilated during the pressing process, and the first substrate 1, the second substrate 2 and the third substrate 3 can form a relatively closed air cavity to reduce the loss caused by the medium. Furthermore, the first air hole 11 can be copper plated after the five-layer substrate is pressed together, and the first air hole 11 can be fully filled with copper material to form an absolutely closed air cavity with the first substrate 1, the second substrate 2 and the third substrate 3.

[0039] In the suspended line filter of the present embodiment, a first air hole 11 is provided on the first substrate 1. The first air hole 11 is used for ventilation when the five-layer substrate is pressed together, so that the inside of the air cavity formed by the first substrate 1, the second substrate 2 and the third substrate 3 is balanced with the external pressure, thereby preventing the first substrate 1, the second substrate 2 and the third substrate 3 from being cracked or deformed when pressed together under high pressure and high temperature conditions; at the same time, condensation is also avoided due to excessive temperature inside the air cavity formed by the first substrate 1, the second substrate 2 and the third substrate 3, and corrosion, mildew and other problems are prevented inside the air cavity formed by the first substrate 1, the second substrate 2 and the third substrate 3, thereby ensuring the reliability of the suspended line filter.

[0040] In one embodiment, if Figure 3 As shown, a side view structural diagram of a suspended line filter is provided. Figure 2 On the basis of the suspended line filter shown, the third substrate 3 is provided with second air holes 33 , and the second air holes 33 are respectively connected to the first hollow structure and the third hollow structure.

[0041] The second air hole 33 can be set at any position on the third substrate 3 that can connect the first hollow structure and the third hollow structure except the line pattern of the filter suspension line 32. The opening position of the second air hole 33 can be opposite to the opening position of the first air hole 11, or the opening position of the second air hole 33 can be not opposite to the opening position of the first air hole 11. The second air hole 33 is used to discharge the gas in the cavity formed by the third substrate 3, the fourth substrate 4 and the fifth substrate 5 through the second air hole 33 to the cavity formed by the first substrate 1, the second substrate 2 and the third substrate 3 when the five-layer substrate is pressed together, and then discharged by the first air hole 11. The size of the second air hole 33 can be the same as the size of the first air hole 11, or the size of the second air hole 33 can be different from the size of the first air hole 11. The size of the second air hole 33 can be set according to the actual application situation. It can be understood that the second air hole 33 does not affect the airtightness of the overall cavity formed by the five-layer substrate. Therefore, it is not necessary to fill the second air hole 33 after the pressing is completed.

[0042] In the suspended line filter of the present embodiment, a second air hole 33 is provided on the third substrate 3, and the second air hole 33 is used to discharge the gas in the cavity formed by the third substrate 3, the fourth substrate 4 and the fifth substrate 5 during pressing. Combined with the first air hole 11, the entire cavity formed by the five-layer substrate can be balanced with the external pressure, and the third air hole will not affect the airtightness of the entire cavity. While protecting each layer of the circuit board during pressing, it can also reduce the loss caused by the dielectric. Furthermore, if a solder pad for connecting the filter to the outside world is provided on the fifth substrate 5, the gas in the cavity formed by the third substrate 3, the fourth substrate 4 and the fifth substrate 5 has been discharged through the second air hole 33, and there is no need to provide an air hole on the fifth substrate 5, so that the solder pad on the fifth substrate 5 will not be affected, thereby ensuring the reliability of the suspended line filter.

[0043] In one embodiment, if Figure 4 As shown, a side view structural diagram of a suspended line filter is provided. Figure 2 On the basis of the suspended line filter shown, a third air hole 51 is provided on the fifth substrate 5 , and the third air hole 51 is connected to the second hollow structure.

[0044] The third air hole 51 can be set in any area on the fifth substrate 5 that can be connected with the second hollow structure. Furthermore, if a solder pad for connecting the suspended line filter to the outside is provided on the fifth substrate 5, the third air hole 51 should be set at a place other than the solder pad on the fifth substrate 5. The third air hole 51 is used to allow the cavity formed by the third substrate 3, the fourth substrate 4 and the fifth substrate 5 to ventilate when the five-layer substrate is pressed together. The third air hole 51 can be metallized or not. The size of the third air hole 51 can be set according to actual application conditions, so that the third air hole 51 can be ventilated during the pressing process, and the third substrate 3, the fourth substrate 4 and the fifth substrate 5 can form a relatively closed air cavity to reduce the loss caused by the medium. When making the solder pad on the fifth substrate 5, the third air hole 51 and the first air hole 11 can be fully filled with copper material, so that the entire cavity formed by the five-layer substrate is an absolutely closed air cavity.

[0045] The suspended line filter of this embodiment is provided with a third air hole 51 on the third substrate 3. The third air hole 51 is used to allow ventilation of the cavity formed by the third substrate 3, the fourth substrate 4 and the fifth substrate 5 when pressed together. Combined with the first air hole 11, the entire cavity formed by the five-layer substrate can be balanced with the external pressure, and the first air hole 11 and the third air hole 51 both directly discharge the gas in the cavity out of the suspended line filter, so that the ventilation effect is better, and each substrate can be better protected.

[0046] In one embodiment, if Figure 5 As shown, a side view structural diagram of a suspended line filter is provided. Figure 3 On the basis of the suspended line filter shown, the opening position of the first air hole 11 is opposite to the opening position of the second air hole 33 .

[0047] Under the premise of ensuring that the second air hole 33 will not damage the filter suspension line 32, the opening position of the first air hole 11 is opposite to the opening position of the second air hole 33, and the gas in the cavity formed by the third substrate 3, the fourth substrate 4 and the fifth substrate 5 can be discharged faster through the first air hole 11 through the third air hole 51.

[0048] In the suspended line filter of this embodiment, the opening position of the first air hole 11 is arranged opposite to the opening position of the second air hole 33, so that the gas in the cavity formed by the third substrate 3, the fourth substrate 4 and the fifth substrate 5 can be discharged faster, thereby better protecting each substrate.

[0049] In one embodiment, if Figure 6 As shown, a side view structural diagram of a suspended line filter is provided. Figure 1On the basis of the suspended line filter shown, electromagnetic shielding metal layers 6 are respectively provided on the surfaces of the first substrate 1 and the fifth substrate 5 .

[0050] It is understandable that the electromagnetic shielding metal layer 6 is a copper layer, the lower surface of the first substrate 1 and the upper surface of the fifth substrate 5 must be provided with an electromagnetic shielding metal layer 6, and the upper surface of the first substrate 1 and the lower surface of the fifth substrate 5 can be provided with a copper layer as needed.

[0051] In the suspended line filter of this embodiment, an electromagnetic shielding metal layer 6 is provided on the first substrate 1 and the fifth substrate 5 for electromagnetic shielding, which can effectively isolate the electromagnetic coupling between the inside and the outside of the suspended line filter and reduce crosstalk between signals.

[0052] In one embodiment, if Figure 7 As shown, a side view structural diagram of a suspended line filter is provided. Figure 1 On the basis of the suspended line filter shown, an adhesive layer 7 is provided between each upper and lower adjacent substrate, and the adhesive layer 7 is a prepreg.

[0053] In the suspended line filter of this embodiment, a semi-cured sheet is arranged between each substrate for lamination. The semi-cured sheet can be insulated to ensure that no short circuit occurs between layers. After the lamination is completed, the semi-cured sheet will cool and solidify to form a strong mechanical bond, which only bonds the layers together and ensures the stability of the suspended line filter.

[0054] In one embodiment, in the above Figure 1 On the basis of the suspended line filter shown, the areas of the first preset area 21 and the second preset area 41 are both larger than the line area 31 .

[0055] Specifically, the first preset area 21 and the second preset area 41 are both larger than the line area 31 , ensuring that the filter transmission line 32 of the line area 31 can be completely located in the cavity.

[0056] In the suspended line filter of this embodiment, the first preset area 21 and the second preset area 41 are both larger than the line area 31, which can ensure that the suspended line filter has a better filtering effect, optimize the electromagnetic compatibility, and ensure signal quality.

[0057] like Figure 8 As shown, a side view structural schematic diagram of a suspended line filter is provided.

[0058] In one embodiment, if Figure 8 As shown in the above Figure 1On the basis of the suspended line filter shown, the suspended line filter further includes a first via hole 81 penetrating through each of the substrates, an output pad 82 is provided on the first substrate 1 or the fifth substrate 5 , and one end of the first via hole 81 is connected to the output pad 82 .

[0059] The first via hole 81 is used to realize the electrical connection between each substrate. The first substrate 1 or the fifth substrate 5 is provided with an output pad 82. The position of the via hole and the position of the pad can be set as needed. The position of the via hole should be set outside the cavity formed by the five-layer substrate. The pad is connected to the via hole so that the suspended line filter can be interconnected with the outside through the pad. Preferably, the suspended line filter is also provided with a third via hole and an input pad that penetrates each substrate. The third via hole is connected to the input pad on the surface of the first substrate 1 or the surface of the fifth substrate 5. The number of the first via hole 81, the third via hole, the input pad and the output pad 82 can be set according to actual conditions.

[0060] The suspended line filter of this embodiment has vias arranged in the suspended line filter, and pads arranged on the surface to connect with the vias, so that the signals of the suspended line filter are interconnected with the outside through the vias and the pads, without the need for additional welding, which is more conducive to mass production of the product.

[0061] In one embodiment, if Figure 8 As shown, based on the above embodiments, the suspended line filter also includes a second via hole 91 penetrating each of the substrates, a ground pad 92 is provided on the first substrate 1 or the fifth substrate 5, and one end of the second via hole 91 is connected to the ground pad 92.

[0062] The number of second via holes 91 and ground pads 92 may be set according to actual application conditions. Preferably, a plurality of second via holes 91 and ground pads 92 are provided, and the plurality of second via holes 91 are connected to the plurality of ground pads 92 respectively.

[0063] The suspended line filter of this embodiment is provided with multiple ground pads 92 and second vias 91, which can reduce impedance and improve the stability of the suspended line filter. The multiple ground pads 92 greatly improve the heat dissipation effect and improve the overall quality and reliability of the suspended line filter.

[0064] The above embodiment is only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model is described in detail with reference to the aforementioned embodiment, a person skilled in the art should understand that the technical solution described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solution from the spirit and scope of the technical solution of each embodiment of the utility model, and should be included in the protection scope of the utility model.

Claims

1. A suspended line filter, characterized in that: The suspended line filter includes at least a first substrate, a second substrate, a third substrate, a fourth substrate and a fifth substrate which are pressed together. The first preset area of ​​the second substrate is set as a first hollow structure, the second preset area of ​​the fourth substrate is set as a second hollow structure, and a filter transmission line is set at the copper layer of the line area of ​​the third substrate.

2. The suspended line filter according to claim 1, characterized in that: The first substrate is provided with a first ventilation hole, and the first ventilation hole is communicated with the first hollow structure.

3. The suspended line filter according to claim 2, characterized in that: The third substrate is provided with second ventilation holes, and the second ventilation holes are respectively connected with the first hollow structure and the third hollow structure.

4. The suspended line filter according to claim 2, characterized in that: The fifth substrate is provided with a third ventilation hole, and the third ventilation hole is communicated with the second hollow structure.

5. The suspended line filter according to claim 3, characterized in that: The opening position of the first ventilation hole is opposite to the opening position of the second ventilation hole.

6. The suspended line filter according to claim 1, characterized in that: Electromagnetic shielding metal layers are respectively disposed on surfaces of the first substrate and the fifth substrate.

7. The suspended line filter according to claim 1, characterized in that: An adhesive layer is provided between each of the upper and lower adjacent substrates, and the adhesive layer is a prepreg.

8. The suspended line filter according to claim 1, characterized in that: The areas of the first preset area and the second preset area are both larger than the circuit area.

9. The suspended line filter according to claim 1, wherein: The suspended line filter further includes a first via hole penetrating through each of the substrates. An output pad is disposed on the first substrate or the fifth substrate. One end of the first via hole is connected to the output pad.

10. The suspended line filter according to claim 9, characterized in that: The suspended line filter further includes a second via hole penetrating through each of the substrates, a ground pad is provided on the first substrate or the fifth substrate, and one end of the second via hole is connected to the ground pad.

Images