Multilayer surface mount filter

Abstract

The utility model discloses a kind of multilayer surface-mounted filters, it is related to microwave filter technical field, the utility model is replaced metal cavity / LTCC by adopting compression process multilayer substrate, avoid cavity bulky structure, overcome the problem of LTCC sintering deformation, realize the size is reduced substantially, simultaneously, by interlayer coupling resonance unit in vertical direction is partially overlapped, it can promote Q value to traditional single layer microstrip 2 times or more, and full-wrapped metal shell can replace traditional partial ground layer, reduce stray radiation leakage, can break through volume, loss, suppression, temperature drift and power and multiple bottleneck, to meet the use demand of filter in harsh environment.

Description

Technical Field

[0001] This utility model belongs to the field of microwave filter technology, and specifically relates to a multilayer surface-mount filter. Background Technology

[0002] In the field of microwave communications, the demand for high-frequency and miniaturized surface-mount filters is increasingly urgent, but existing technologies have significant limitations. While metal cavity filters offer high power capacity and excellent rectangular coefficients, their large physical size makes integration into modern compact devices difficult. Miniaturization solutions using single-layer microstrip or organic substrates suffer from low Q values, leading to insufficient key performance characteristics: insertion loss is generally higher than 2.5dB, in-band ripple exceeds 1.5dB, and power tolerance is often below 2W. Furthermore, organic materials exhibit significant dielectric constant drift over a wide temperature range of -55℃ to +85℃, causing frequency shift and VSWR degradation, failing to meet harsh environmental requirements. Although low-temperature co-fired ceramic filters achieve miniaturization through multilayer structures, their sintering process easily introduces interlayer alignment misalignment, weakening the coupling accuracy of resonant units and resulting in insufficient out-of-band suppression. The complex process also increases manufacturing costs. In addition, existing surface-mount designs often rely on planar resonant structures, resulting in low interlayer coupling efficiency, limiting the improvement of the rectangular coefficient. Inadequate grounding and shielding can easily lead to stray coupling, further degrading in-band flatness and suppression depth. Utility Model Content

[0003] In view of the deficiencies in the prior art, this utility model provides a multilayer surface-mount filter to solve the above-mentioned technical problems.

[0004] A multilayer surface-mount filter includes the following components:

[0005] A multilayer dielectric substrate, wherein the multilayer dielectric substrate is formed into an integral structure through a lamination process;

[0006] Multiple resonant units disposed on different layers inside the multilayer dielectric substrate, the multiple resonant units forming a filter network through interlayer coupling;

[0007] An input feed line and an output feed line are disposed on the surface of the multilayer dielectric substrate, and the input feed line and the output feed line are respectively coupled to both ends of the filter network;

[0008] The outer surface of the multilayer dielectric substrate is provided with a metal shell, and the metal shell has two openings. The metal shell is exposed at the openings, and the input feed line and the output feed line are respectively disposed in the two openings.

[0009] Preferably, the resonant unit is provided with an electromagnetic hybrid coupler.

[0010] Preferably, the resonant units of adjacent layers at least partially overlap in the vertical direction.

[0011] Preferably, the two openings are located at opposite ends of the same surface of the multilayer dielectric substrate.

[0012] Preferably, the system also includes metallized vias that penetrate part or all of the multilayer dielectric substrate, the metallized vias being used to achieve interlayer electrical connection and shielding.

[0013] Preferably, the multilayer dielectric substrate is made of temperature-stable ceramic material or high-frequency PCB substrate material to ensure stable filter performance within a temperature range of -55℃ to +85℃.

[0014] Preferably, the filter operates in the frequency band of 8.0 GHz to 10.0 GHz, has a center insertion loss of less than or equal to 1.8 dB, and an in-band ripple of less than or equal to 1.0 dB.

[0015] Preferably, the filter has a suppression of greater than or equal to 40dB in the DC-6.6GHz frequency band and a suppression of greater than or equal to 40dB in the 2.4GHz to 6.5GHz frequency band.

[0016] Preferably, the input voltage standing wave ratio (VSWR) and output voltage standing wave ratio (VSWR) of the filter are less than or equal to 1.8.

[0017] Preferably, the filter is capable of withstanding 5W of continuous wave power.

[0018] The beneficial effects of this utility model are as follows: This solution replaces the metal cavity / LTCC with a multilayer substrate using a lamination process, avoiding the bulky structure of the cavity and overcoming the problem of LTCC sintering deformation, thus achieving a significant reduction in size. At the same time, by partially overlapping the interlayer coupled resonant units in the vertical direction, the Q value can be improved to more than twice that of the traditional single-layer microstrip. Furthermore, the fully enclosed metal shell can replace the traditional local grounding layer, reducing stray radiation leakage. This solution can overcome multiple bottlenecks such as volume, loss, suppression, temperature drift, and power, thereby meeting the requirements of the filter in harsh environments. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A bottom view of a multilayer surface-mount filter provided by this utility model;

[0021] Figure 2A side view of a multilayer surface-mount filter provided by this utility model;

[0022] Figure 3 A top view of a multilayer surface-mount filter provided by this utility model;

[0023] Legend: 1-Multilayer dielectric substrate, 2-Input feed line, 3-Output feed line, 4-Opening. Detailed Implementation

[0024] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0025] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this invention.

[0026] The embodiments of the utility model will now be described in detail with reference to the accompanying drawings.

[0027] like Figure 1 As shown, a multilayer surface-mount filter includes the following components:

[0028] Multilayer dielectric substrate, the multilayer dielectric substrate is formed into an integral structure through a lamination process;

[0029] Multiple resonant units are disposed on different layers inside the multilayer dielectric substrate 1, and the multiple resonant units form a filter network through interlayer coupling.

[0030] Input feed line 2 and output feed line 3 are disposed on the surface of multilayer dielectric substrate 1, and input feed line 2 and output feed line 3 are respectively coupled to both ends of the filter network;

[0031] The outer surface of the multilayer dielectric substrate 1 is provided with a metal shell, and the metal shell has two openings 4. The metal shell is exposed at the openings, and the input feed line 2 and the output feed line 3 are respectively disposed in the two openings 4.

[0032] This solution replaces the metal cavity / LTCC with a multilayer substrate using a lamination process, avoiding the bulky cavity structure and overcoming the deformation problem of LTCC sintering, thus achieving a significant reduction in size. At the same time, by partially overlapping the interlayer coupled resonant units in the vertical direction, the Q value can be improved to more than twice that of the traditional single-layer microstrip. Furthermore, the fully enclosed metal shell can replace the traditional local grounding layer, reducing stray radiation leakage. This solution can overcome multiple bottlenecks such as size, loss, suppression, temperature drift, and power, thus meeting the requirements of the filter for use in harsh environments.

[0033] like Figure 2 , Figure 3 As shown, in this scheme, the multilayer dielectric substrate has a length of 8±0.2mm, a width of 3.6±0.2mm, and a thickness of 1.3±0.2mm;

[0034] The opening has a length of 0.9 mm and a width of 1.2 mm along the multilayer dielectric substrate. The input / output feed line has a length of 0.5 mm and a width of 0.4 mm along the multilayer dielectric substrate.

[0035] The input and output feed lines here can be microstrip lines or coplanar waveguide structures.

[0036] More specifically, the resonant unit is equipped with an electromagnetic hybrid coupler.

[0037] By integrating an electromagnetic hybrid coupler on the resonant unit, this filter overcomes the limitations of traditional single-mode coupling, reducing the number of resonant units by 50% while maintaining the same performance, and further minimizing the size.

[0038] More specifically, the resonant units of adjacent layers overlap at least partially in the vertical direction.

[0039] By ensuring that adjacent resonant units overlap at least partially in the vertical direction to enhance interlayer coupling, this mounting method can significantly improve the near-field coupling strength between layers in the filter.

[0040] More specifically, the two openings are located at opposite ends of the same surface of the multilayer dielectric substrate 1.

[0041] By positioning the openings of the input / output feed lines at opposite ends on the same surface of the substrate, the signal path can be minimized, the electromagnetic field distribution can be balanced, and it is compatible with automated mounting processes.

[0042] More specifically, it also includes metallized vias that penetrate part or all of the multilayer dielectric substrate 1, used to achieve interlayer electrical connection and shielding.

[0043] The grounding via is connected to the metal grounding layer.

[0044] More specifically, the multilayer dielectric substrate 1 is made of temperature-stable ceramic materials or high-frequency PCB substrate materials.

[0045] By using temperature-stable ceramic materials or high-frequency PCB substrate materials to make multilayer dielectric substrates, the filter can ensure stable performance in the temperature range of -55℃ to +85℃, reducing heat accumulation and center loss voltage.

[0046] More specifically, the filter operates in the frequency band of 8.0 GHz to 10.0 GHz, with a center insertion loss of less than or equal to 1.8 dB and an in-band ripple of less than or equal to 1.0 dB.

[0047] By precisely limiting the filter's operating frequency band to 8.0-10.0GHz and achieving a center insertion loss of ≤1.8dB and an in-band ripple of ≤1.0dB, the loss is significantly reduced in the 8GHz band compared to traditional filters, thus achieving the effect of suppressing ripple.

[0048] More specifically, the filter has a suppression of greater than or equal to 40dB in the DC-6.6GHz frequency band and a suppression of greater than or equal to 40dB in the 2.4GHz to 6.5GHz frequency band.

[0049] By achieving a ≥40dB depth of suppression in both DC-6.6GHz and 2.4-6.5GHz dual stopbands, this filter can eliminate the blocking interference of DC-6.6GHz ultrawide low-frequency spurious signals to millimeter-wave receivers. At the same time, it can also reduce out-of-band spurious radiation thanks to its sharp cutoff characteristic with a stopband steepness of 60dB / GHz.

[0050] More specifically, the input voltage standing wave ratio (VSWR) and output voltage standing wave ratio (VSWR) of the filter are less than or equal to 1.8.

[0051] In traditional solutions, a VSWR > 2.0 will cause EVM to exceed the limit. However, in this solution, by limiting the input / output voltage VSWR to ≤ 1.8, the signal reflection loss can be compressed to ≤ 2%, which greatly improves the passband energy transmission efficiency. At the same time, it can also optimize the error vector amplitude of 256QAM modulation in 5G base stations and improve the high-frequency spectrum utilization.

[0052] More specifically, the filter can withstand 5W of continuous wave power.

[0053] By achieving a 5W continuous wave power capacity, this filter effectively helps reduce the power consumption of millimeter-wave devices and improve device integration by leveraging the heat dissipation effect of multi-layer dielectrics.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A multilayer surface-mount filter, characterized in that, The system includes the following components: a multilayer dielectric substrate (1), which is formed into an integral structure by a lamination process; multiple resonant units disposed on different layers inside the multilayer dielectric substrate (1), which form a filter network through interlayer coupling; an input feed line (2) and an output feed line (3) disposed on the surface of the multilayer dielectric substrate (1), which are respectively coupled to the two ends of the filter network; a metal shell is provided on the outer surface of the multilayer dielectric substrate (1), and two openings (4) are opened on the metal shell, which are exposed at the openings, and the input feed line (2) and the output feed line (3) are respectively disposed in the two openings (4).

2. The multilayer surface-mount filter according to claim 1, characterized in that, The resonant unit is equipped with an electromagnetic hybrid coupler.

3. The multilayer surface-mount filter according to claim 2, characterized in that, The resonant units of adjacent layers overlap at least partially in the vertical direction.

4. The multilayer surface-mount filter according to claim 1, characterized in that, The two openings (4) are located at opposite ends of the same surface of the multilayer dielectric substrate (1).

5. The multilayer surface-mount filter according to claim 1, characterized in that, It also includes metallized vias that penetrate part or all of the multilayer dielectric substrate (1), the metallized vias being used to achieve interlayer electrical connection and shielding.

6. The multilayer surface-mount filter according to claim 1, characterized in that, The multilayer dielectric substrate (1) is made of temperature-stable ceramic material or high-frequency PCB substrate material to ensure that the filter has stable performance in the temperature range of -55℃ to +85℃.

7. The multilayer surface-mount filter according to claim 1, characterized in that, The filter operates in the frequency band of 8.0 GHz to 10.0 GHz, with a center insertion loss of less than or equal to 1.8 dB and an in-band ripple of less than or equal to 1.0 dB.

8. The multilayer surface-mount filter according to claim 1, characterized in that, The filter has a suppression of greater than or equal to 40dB in the DC-6.6GHz frequency band and a suppression of greater than or equal to 40dB in the 2.4GHz to 6.5GHz frequency band.

9. The multilayer surface-mount filter according to claim 1, characterized in that, The input voltage standing wave ratio (VSWR) and output voltage standing wave ratio (VSWR) of the filter are less than or equal to 1.

8.

10. The multilayer surface-mount filter according to claim 1, characterized in that, The filter can withstand 5W of continuous wave power.

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