CN116781025A - Filtering structure and preparation method thereof - Google Patents

Abstract

The application provides a filtering structure and a preparation method thereof, wherein the filtering structure comprises a ceramic matrix, and an inductance element and a capacitance element which are arranged in the ceramic matrix; the ceramic substrate is provided with an input end electrode for accessing signal waves and an output end electrode for outputting the signal waves, and the capacitor piece, the inductor piece, the input end electrode and the output end electrode are electrically connected to filter the accessed signal waves; according to the application, the inductance component is arranged to be of a sheet structure, and the inductance component is overlapped with the first polar plate and the second polar plate of the capacitance component, so that the steps of punching and hole filling are not needed, and the problem that the performance of the filter is influenced due to the hole filling process is avoided; on the other hand, compared with the traditional vertical spiral inductor, the inductor with the sheet structure has smaller parasitic capacitance, especially under the high-frequency condition, and is beneficial to improving the electrical performance of the filtering structure.

Description

Filtering structure and preparation method thereof

Technical Field

The application belongs to the technical field of filters, and particularly relates to a filtering structure and a preparation method thereof.

Background

In the current filter structure, low-temperature co-fired ceramic (Low Temperature Cofired Ceramic, LTCC) technology is mostly used to integrate the inductive and capacitive elements into a ceramic substrate to form a monolithic structure.

However, such filters require different structures to be perforated and filled before being combined. In the hole filling process, metal slurry is required to be filled into each hole to form a blind hole, and in the process, a gap is easily generated, so that the inside is broken, and the performance of the filter is affected.

Therefore, the conventional ceramic-based filter structure has a problem that the filter performance is affected by the pore-filling process.

Disclosure of Invention

The application aims to provide a filter structure and a preparation method thereof, and aims to solve the problem that the performance of a filter is affected due to a pore-filling process in the traditional ceramic-based filter structure.

A first aspect of an embodiment of the present application provides a filtering structure, including a ceramic substrate, where an input end electrode and an output end electrode are disposed on the ceramic substrate, the input end electrode is used for accessing a signal wave, and the output end electrode is used for outputting the signal wave; wherein the output end electrode and the input end electrode are arranged at opposite intervals;

the inductance piece is of a sheet structure, is arranged in the ceramic matrix, spans between the input end electrode and the output end electrode and is electrically connected with the input end electrode and the output end electrode;

the capacitor piece is arranged in the ceramic substrate and comprises a first polar plate and a second polar plate which are oppositely arranged at intervals, a first capacitor is formed between the first polar plate and the second polar plate, and the first polar plate and the second polar plate are stacked on the inductor piece;

the ceramic substrate is further provided with a grounding end electrode, and the first polar plate and the second polar plate are connected between any two of the input end electrode, the output end electrode and the grounding end electrode, so that the first capacitor is electrically connected with the inductance element.

In some embodiments of the present application, the capacitor further includes a third electrode plate, where the third electrode plate is relatively disposed at a side of the second electrode plate facing away from the first electrode plate at intervals, and a second capacitor is formed between the third electrode plate and the second electrode plate;

the first electrode plate is electrically connected with the grounding end electrode, the second electrode plate is electrically connected with the input end electrode, the third electrode plate is electrically connected with the output end electrode, so that the first capacitor is grounded, and the second capacitor and the inductance element form a resonance structure.

In some embodiments of the present application, the capacitor further includes a fourth electrode plate, where the fourth electrode plate is disposed at a side of the third electrode plate facing away from the second electrode plate, and a third capacitor is disposed between the fourth electrode plate and the third electrode plate;

the fourth polar plate is electrically connected with the grounding terminal electrode so as to enable the third capacitor to be grounded.

In some embodiments of the present application, the ground electrode is disposed between the input electrode and the output electrode; the first polar plate is provided with a first protruding part which is connected with the grounding terminal electrode; and/or a second protruding part is arranged on the fourth polar plate, and the second protruding part is connected with the grounding terminal electrode.

In some embodiments of the present application, the ground electrode includes a first sub-port and a second sub-port; the first sub-port and the second sub-port are respectively arranged on two sides of the first polar plate, the number of the first protruding parts is two, one of the two first protruding parts is connected with the first sub-port, and the other is connected with the second sub-port;

and/or the first sub-port and the second sub-port are respectively arranged at two sides of the fourth polar plate, the number of the second protruding parts is two, one of the two second protruding parts is connected with the first sub-port, and the other is connected with the second sub-port.

In some embodiments of the present application, the first capacitor and the third capacitor have the same capacitance value.

In some embodiments of the present disclosure, the inductance element has a bending section that is bent in a first plane, the bending section having a first subsection and a second subsection that are disposed adjacent to each other, and a current direction of the first subsection is opposite to a current direction of the second subsection; wherein the first plane is parallel to the first polar plate and/or the second polar plate.

In some embodiments of the present application, the inductance element has a lead-in section and a lead-out section disposed at two ends of the bending section, one end of the lead-in section facing away from the bending section is connected to the input terminal electrode, and one end of the lead-out section facing away from the bending section is connected to the output terminal electrode;

wherein the width of the introducing section in the current flow direction is larger than the width of the bending section in the current flow direction; and/or the width of the leading-out section in the current flow direction is larger than the width of the bending section in the current flow direction; the current flow direction of the current flow direction is the current flow direction in the induction element.

In a second aspect, the present application further provides a method for preparing a filtering structure, for preparing the filtering structure, where the preparation method includes:

providing a first dielectric film layer, and arranging a sensing element on the first dielectric film layer;

a second dielectric film layer is overlapped on the first dielectric film layer and at least partially covers the inductance component;

a first polar plate is arranged on one side of the second dielectric film layer, which is away from the first dielectric film layer;

a third dielectric film layer is overlapped on the second dielectric film layer and at least partially covers the first polar plate;

a second polar plate is arranged on one side of the third dielectric film layer, which is away from the second dielectric film layer; and a first capacitor is formed between the first polar plate and the second polar plate, and the first capacitor is electrically connected with the inductance element.

In some embodiments of the present application, after the step of disposing the second electrode plate on a side of the third dielectric film layer facing away from the second dielectric film layer, the method for manufacturing the filtering structure further includes:

a fourth dielectric film layer is overlapped on the third dielectric film layer and at least covers the second polar plate;

a third polar plate is arranged on one side, away from the third dielectric film layer, of the fourth dielectric film layer, a second capacitor is formed between the third polar plate and the second polar plate, and the second capacitor is coupled to two ends of the inductance element;

a fifth dielectric film layer is overlapped on the fourth dielectric film layer and at least covers the third polar plate;

and a fourth polar plate is arranged on one side of the fifth dielectric film layer, which is away from the fourth dielectric film layer, a third capacitor is formed between the fourth polar plate and the third polar plate, one end of the third capacitor is connected with the output end of the inductor, and the other end of the third capacitor is grounded.

Compared with the prior art, the embodiment of the application has the beneficial effects that: in the above filtering structure and the preparation method thereof, the filtering structure comprises a ceramic matrix, and an inductance element and a capacitance element which are arranged in the ceramic matrix; the ceramic substrate is provided with an input end electrode for accessing signal waves and an output end electrode for outputting the signal waves, and the capacitor piece, the inductor piece, the input end electrode and the output end electrode are electrically connected to filter the accessed signal waves; according to the application, the inductance component is arranged to be of a sheet structure, and the inductance component is overlapped with the first polar plate and the second polar plate of the capacitance component, so that the steps of punching and hole filling are not needed, and the problem that the performance of the filter is influenced due to the hole filling process is avoided; on the other hand, compared with the traditional vertical spiral inductor, the inductor with the sheet structure has smaller parasitic capacitance, especially under the high-frequency condition, and is beneficial to improving the electrical performance of the filtering structure.

Drawings

Fig. 1 is a schematic structural diagram of a filtering structure according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a filtering structure according to another embodiment of the present application;

FIG. 3 is a side view of a filter structure according to an embodiment of the present application;

FIG. 4 is a cross-sectional view taken along the direction A-A of FIG. 3 in accordance with one embodiment of the present application;

FIG. 5 is a schematic structural diagram of a sensor according to an embodiment of the present application;

fig. 6 is a schematic circuit diagram of a filtering structure according to an embodiment of the application;

FIG. 7 is a graph showing the test results of a 3200MHz low pass filter with cutoff frequency according to one embodiment of the present application;

FIG. 8 is a schematic diagram illustrating steps of a method for fabricating a filter structure according to an embodiment of the present application;

fig. 9 is a schematic step diagram of a method for manufacturing a filter structure according to another embodiment of the present application.

Specific element symbol description: 100-ceramic matrix, 110-input electrode, 120-output electrode, 130-ground electrode, 131-first sub-port, 132-second sub-port, 200-inductor, 210-lead-in section, 220-lead-out section, 230-bend section, 231-first sub-section, 232-second sub-section, 300-capacitor, 310-first plate, 311-first boss, 320-second plate, 330-third plate, 340-fourth plate, 341-second boss.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "length," "width," "upper," "lower," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, and are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

It should be noted that the filter is an indispensable element in the microwave system. With the continuous development of miniaturization, light weight and high performance of the current microwave system, higher requirements are put on the size and performance of the device. Conventional filters include reactance elements such as capacitors and inductors, which are typically directly soldered to the circuit, but have a large footprint and generate large parasitic capacitances or inductances at high frequencies, which makes it difficult to meet the requirements of the rf circuit.

In the related art, LTCC technology is used to integrate the reactance elements of a filter into a ceramic matrix to form a monolithic structure. Therefore, the size of the filter can be reduced, the integration level and the reliability of the filter can be improved, and the use frequency of the filter can be improved. However, in the current ceramic-based filter structure, a vertical spiral inductor and a vertical interdigital capacitor are generally adopted; in the process of preparing the filter structure, holes are punched first, and then metal paste is filled into each hole through a hole filling process, so that inductance and capacitance are formed. Because the void is easy to be generated during hole filling, the inductance or the capacitance in the filtering structure is easy to form broken lines, so that the filtering structure is bad and the performance of the filtering structure is influenced.

In addition, parasitic parameters are introduced into the vertical spiral inductor and the vertical interdigital capacitor, so that the electrical performance of the filter capacitor is reduced. The application is therefore based on the improvement of the relevant filter structure and its method of preparation.

Referring to fig. 1 and fig. 2 in combination, fig. 1 shows a schematic structural diagram of a filtering structure provided in this embodiment, and fig. 2 shows a schematic partial explosion structural diagram of the filtering structure provided in this embodiment. The filter structure of the present embodiment includes a ceramic base 100, and an inductance element 200 and a capacitance element 300 provided in the ceramic base 100. It can be understood that the ceramic base 100 is provided with a receiving cavity, and the inductance element 200 and the capacitance element 300 are disposed in the receiving cavity, so that the volume is reduced, and the inductance element 200 and the capacitance element 300 can be protected. That is, the ceramic body 100 can be coated outside the inductance component 200 and the capacitance component 300, and form a unitary structure.

Specifically, the ceramic substrate 100 is provided with an input electrode 110 and an output electrode 120, the input electrode 110 is used for receiving signal waves, and the output electrode 120 is used for outputting the signal waves. It should be noted that, the input terminal electrode 110 is used for receiving the signal wave to be filtered, and the output terminal electrode 120 is used for outputting the filtered signal wave. Wherein the output electrode 120 is disposed at a distance from the input electrode 110. That is, there is a space between the output terminal electrode 120 and the input terminal electrode 110 so that the inductive member 200 and the capacitive member 300 are provided.

The inductor 200 has a sheet-like structure, that is, the inductor 200 can be arranged in the same plane, which is beneficial to reducing the thickness of the whole structure. The inductor 200 is disposed between the input electrode 110 and the output electrode 120, and is electrically connected to the input electrode 110 and the output electrode 120. That is, the inductor 200 has one end connected to the input terminal electrode 110 and the other end connected to the output terminal electrode 120. The inductor 200 itself can have a certain low-pass filtering effect, and can block the high-frequency signal wave from flowing from the input terminal electrode 110 to the output terminal electrode 120.

The capacitor 300 is disposed in the ceramic substrate 100, and the capacitor 300 includes a first electrode plate 310 and a second electrode plate 320 disposed at opposite intervals, and a first capacitor is formed between the first electrode plate 310 and the second electrode plate 320. It should be explained that, the first electrode plate 310 and the second electrode plate 320 are both planar structures, and two opposite planar structures are adopted to form the first capacitor, so that parasitic parameters of the first capacitor are lower, and electrical performance of the first capacitor in the circuit structure is improved. The first electrode plate 310 and the second electrode plate 320 are stacked on the inductor 200, which is beneficial to reducing the space occupation of the inductor 200 and the capacitor 300 in the thickness direction, and further making the filtering structure thinner.

More specifically, the ceramic substrate 100 is further provided with a ground electrode 130, and the first electrode plate 310 and the second electrode plate 320 are connected between any two of the input electrode 110, the output electrode 120 and the ground electrode 130, so that the first capacitor is electrically connected with the inductor 200. It should be noted that, when the first electrode plate 310 and the second electrode plate 320 are respectively connected to the input terminal electrode 110 and the output terminal electrode 120, the first capacitor is used as the resonance capacitor of the inductor 200, which is beneficial to improving the filtering effect. When the first electrode plate 310 and the second electrode plate 320 are respectively connected to the input terminal electrode 110 and the ground terminal electrode 130, the first capacitor and the inductor 200 form an LC low-pass filter structure (L-shape). When the first electrode plate 310 and the second electrode plate 320 are respectively connected to the output electrode 120 and the ground electrode 130, the first capacitor and the inductor 200 form an LC low-pass filter structure (L-shape).

It should be noted that, in the LC low-pass filter structure, the self-inductance characteristic of the inductor 200 can perform a low-pass filtering effect, the first capacitor is grounded to enable the high-frequency signal wave to be guided away, and the low-frequency signal wave cannot pass through the first capacitor, which is equivalent to the low-pass filtering effect. That is, a two-layer filtering structure can be formed, and the low-pass filtering effect can be further improved.

In the current ceramic-based filter structure, the inductor 200 and the capacitor 300 are prepared by punching and filling holes, so that the performance of the filter structure is unstable and has larger parasitic capacitance. However, in the present application, the inductance element 200 is configured as a sheet structure, and the inductance element 200 is stacked with the first electrode plate 310 and the second electrode plate 320 of the capacitance element 300, so that on one hand, the steps of punching and hole filling are not required, and the problem that the filter performance is affected due to the hole filling process is avoided; on the other hand, the inductance component 200 with the sheet structure has smaller parasitic capacitance compared with the conventional vertical spiral inductance, especially under the high-frequency condition, which is beneficial to improving the electrical performance of the filtering structure.

In some embodiments of the present application, please continue to refer to fig. 3 and fig. 4, fig. 3 is a side view of the filtering structure provided in the present embodiment; fig. 3 is a cross-sectional view A-A of fig. 3 provided in this embodiment. The capacitor 300 of the present embodiment further includes a third electrode 330, where the third electrode 330 is disposed opposite to the second electrode 320 at a side facing away from the first electrode 310, and a second capacitor is formed between the third electrode 330 and the second electrode 320. That is, the third electrode 330 is stacked with the second electrode 320, the first electrode 310 and the inductor 200. It should be noted that, the surface of one side of the second plate 320 is used as one of the poles of the first capacitor, and the surface of the other side is used as one of the poles of the second capacitor, which is beneficial to reducing the overall thickness of the capacitor 300, reducing the screen printing required in the molding process, and simplifying the molding process.

Specifically, referring to fig. 5, fig. 5 shows a circuit diagram of a filtering structure provided in the present embodiment; the first electrode plate 310 is electrically connected to the ground electrode 130, the second electrode plate 320 is electrically connected to the input electrode 110, and the third electrode plate 330 is electrically connected to the output electrode 120, so that the first capacitor is grounded, and the second capacitor and the inductor 200 form a resonant structure. That is, the first capacitor and the inductor 200 can form an LC low-pass filter structure, and the second capacitor is connected in parallel to two ends of the inductor 200 to form a resonant structure therewith.

In some embodiments of the present application, referring to fig. 4, the capacitor 300 of the present embodiment further includes a fourth electrode 340, and the fourth electrode 340 is disposed on a side of the third electrode 330 facing away from the second electrode 320 at a distance, and a third capacitor is disposed between the fourth electrode 340 and the third electrode 330. That is, the fourth electrode 340 is stacked with the third electrode 330, the second electrode 320, the first electrode 310, and the inductor 200. It should be noted that, the third electrode 330 has one side surface serving as one of the poles of the second capacitor and the other side surface serving as one of the poles of the third capacitor, which is beneficial to reducing the overall thickness of the capacitor 300, and reducing the screen printing plate required in the molding process, which is beneficial to simplifying the molding process.

Specifically, with continued reference to fig. 5, the fourth electrode 340 is electrically connected to the ground electrode 130, so as to ground the third capacitor. That is, the third capacitor can form an LC low-pass filter structure with the inductor 200, and the first capacitor and the inductor 200 form an LC low-pass filter structure, and thus, the first capacitor, the third capacitor, and the inductor 200 can form an LC low-pass filter structure (pi type). Compared with a T-shaped structure, the pi-shaped structure has more stable filtering performance and more excellent filtering effect. More specifically, the filtering structure of the present embodiment is a third-order filter, and has a very excellent filtering effect. Wherein the first capacitor and the inductor 200 form a first stage filter structure, the second capacitor and the inductor 200 form a second stage filter structure, and the third capacitor and the inductor 200 form a third stage filter structure.

In some embodiments of the present application, referring to fig. 2 and 4, the ground electrode 130 is disposed between the input electrode 110 and the output electrode 120 in the present embodiment, so that the ground electrode 130 forms an electrical connection structure with the electrode plates between the input electrode 110 and the output electrode 120, and is beneficial to improving the space utilization.

In some embodiments, the first electrode plate 310 is provided with a first protruding portion 311, and the first protruding portion 311 is connected to the ground electrode 130. Specifically, the first protruding portion 311 protrudes along the extension direction of the first plate 310; that is, the first protruding portion 311 is disposed in the same plane as the first electrode plate 310. In some embodiments, the fourth electrode 340 is provided with a second protruding portion 341, and the second protruding portion 341 is connected to the ground electrode 130. Specifically, the second protruding portion 341 protrudes along the extending direction of the fourth electrode 340; that is, the second protruding portion 341 is provided in the same plane as the fourth electrode 340. More specifically, the first protruding part 311 and/or the second protruding part 341 form a connection structure with the electrode by welding.

In some embodiments of the present application, referring to fig. 1, the ground electrode 130 of the present embodiment includes a first sub-port 131 and a second sub-port 132. It will be appreciated that the first sub-port 131 and the second sub-port 132 are both grounded. Specifically, the first sub-port 131 and the second sub-port 132 are separately disposed at both sides of the first plate 310 and disposed on the outer surface of the ceramic body 100, the number of the first protrusions 311 is two, one of the two first protrusions 311 is connected to the first sub-port 131, and the other is connected to the second sub-port 132. That is, the first electrode plate 310 can be grounded through the first sub-port 131 and the second sub-port 132 at the same time, so that the grounding stability of the first electrode plate 310 is improved. Meanwhile, the first sub-port 131 and the second sub-port 132 are disposed at two sides of the first polar plate 310 and are connected with the first protruding portions 311 at two sides, which is beneficial to improving structural stability between the first polar plate 310 and the grounding port, and further beneficial to improving structural stability of the filtering structure.

In a more specific embodiment, the first sub-port 131 and the second sub-port 132 are disposed on both sides of the fourth plate 340, the number of the second protrusions 341 is two, and one of the two second protrusions 341 is connected to the first sub-port 131, and the other is connected to the second sub-port 132. That is, the fourth electrode 340 can be grounded through both the first sub-port 131 and the second sub-port 132, improving the grounding stability of the fourth electrode 340. Meanwhile, the first sub-port 131 and the second sub-port 132 are disposed at two sides of the fourth plate 340 and connected with the first protrusions 311 at two sides, which is beneficial to improving structural stability between the fourth plate 340 and the ground port, and further beneficial to improving structural stability of the filtering structure.

In some embodiments, the output terminal electrode 120 and the input terminal electrode 110 are disposed at both ends of the ceramic body 100, and the ground terminal electrode 130 is disposed at a central position of the outer surface of the ceramic body 100. Specifically, the ceramic substrate 100 is provided with openings at both ends thereof, and the output terminal electrode 120 and the input terminal electrode 110 extend at least partially to the openings so that the second electrode plate 320 and the third electrode plate 330 inside the ceramic substrate 100 are electrically connected.

In some embodiments, the output electrode 120 includes a three-layer structure, the innermost layer being made of silver paste material, the middle layer being made of nickel material, and the outermost layer being made of tin material. Specifically, the silver paste content of the innermost layer is 60% +/-20%, and the sintering temperature of the silver paste is less than or equal to 800 ℃.

In some embodiments, the ceramic matrix 100 is made from a low temperature co-fired ceramic powder having a firing temperature of 900 ℃ or less, a dielectric constant of 6.3 to 7.8, and a dielectric loss factor tan alpha of 0.002 or less.

In some embodiments of the present application, the first capacitor and the third capacitor have the same capacitance value. The capacitance values of the first capacitor and the second capacitor are equal according to the interference signal frequency and the power factor, namely the voltage and current phases, so that the power factor is close to 1, and the capacitance reactance and the reactance are equal when the impedance is matched.

In some embodiments of the present application, referring to fig. 6, fig. 6 shows a schematic structural diagram of a sensing element 200 according to the present embodiment; the inductor 200 of the present embodiment has a bending section 230 bent in a first plane, the bending section 230 has a first subsection 231 and a second subsection 232 disposed adjacently, and the current direction of the first subsection 231 is opposite to the current direction of the second subsection 232; an inductive structure can be formed by the first 231 and second 232 sub-sections. Specifically, the first plane is parallel to the first plate 310 and/or the second plate 320. That is, the inductance element 200 has a planar spiral structure, and the parasitic capacitance of the inductance can be reduced.

In some embodiments of the present application, referring to fig. 6, the inductor 200 of the present embodiment has a lead-in section 210 and a lead-out section 220 disposed at two ends of a bending section 230, wherein one end of the lead-in section 210 facing away from the bending section 230 is connected to the input terminal electrode 110, and one end of the lead-out section 220 facing away from the bending section 230 is connected to the output terminal electrode 120. That is, inductor 200 is connected to input electrode 110 via lead-in section 210 and is connected to output electrode 120 via lead-out section 220.

Specifically, the width of lead-in section 210 in the direction of its current flow is greater than the width of bending section 230 in the direction of its current flow; and/or the width of the lead-out section 220 in the current flow direction thereof is greater than the width of the bending section 230 in the current flow direction thereof; the current flow direction is the flow direction of the current in the inductor 200. The provision of a wider lead-out section 220 is advantageous in improving the reliability of its connection with the output terminal electrode 120. The provision of a wider lead-in section 210 is advantageous in improving the reliability of its connection to the input terminal electrode 110.

In some embodiments, the width of the lead-in section 210 and the lead-out section 220 is 0.25-0.5mm.

The filter structure of the present application can be used as a filter having a frequency of 3000MHz or more. The method can be particularly used in the fields of harmonic suppressors, microwave transmitters/receivers, digital-to-analog converters in DC-DC modules, microwave communication, radar navigation, satellite communication, automobile electronics, electronic countermeasure and the like.

Referring to fig. 7, fig. 7 shows a graph of test results of a 3200MHz low pass filter with a cutoff frequency according to the present embodiment. The filter structure of the embodiment is made into a low-pass filter with small insertion loss, the cut-off frequency of the low-pass filter is 3196MHz, and the insertion loss in the passband is @ DC MHz-2300 MHz and is less than or equal to 1.0dB; stop band inhibition @4400MHz is more than or equal to 20dB; the @ 4800-5400 MHz is more than or equal to 30dB; and @10000MHz is more than or equal to 20dB.

Further, in order to better implement the filtering structure, the present embodiment further provides a method for manufacturing the filtering structure in any of the foregoing embodiments, on the basis of the filtering structure. The preparation method comprises the following steps:

s100: a first dielectric film layer is provided, and the inductor 200 is disposed on the first dielectric film layer. Specifically, the first dielectric film layer is a blank dielectric film. The inductive element 200 may be printed on the first dielectric film layer by a printing process. Before S100, a marking electrode may be printed on the first dielectric film layer, where the marking electrode and the inductor 200 are separately disposed on two sides of the first dielectric film layer.

S200: a second dielectric layer is stacked on the first dielectric layer and at least partially covers the inductor 200. Specifically, the second dielectric film layer is a blank dielectric film. In some embodiments, the second dielectric film completely covers the inductive element 200.

S300: a first plate 310 is disposed on a side of the second dielectric film facing away from the first dielectric film. Specifically, the first plate 310 may be printed on the second dielectric film layer through a printing process.

S400: a third dielectric film layer is stacked on the second dielectric film layer and at least partially covers the first plate 310. Specifically, the third dielectric film layer is a blank dielectric film. In some embodiments, the third dielectric film completely covers the first plate 310.

S500: a second polar plate 320 is arranged on one side of the third dielectric film layer, which is away from the second dielectric film layer; the first capacitor is formed between the first electrode plate 310 and the second electrode plate 320, and the first capacitor is electrically connected to the inductor 200. Specifically, the second plate 320 may be printed on the third dielectric film layer through a printing process.

In some embodiments of the present application, after step S500, the method for manufacturing a filtering structure further includes:

s600: a fourth dielectric film layer is stacked on the third dielectric film layer and covers at least the second electrode plate 320. Specifically, the fourth dielectric film layer is a blank dielectric film. In some embodiments, the fourth dielectric film completely covers the second pole plate 320.

S700: a third electrode plate 330 is disposed on a side of the fourth dielectric film facing away from the third dielectric film, and a second capacitor is formed between the third electrode plate 330 and the second electrode plate 320, and the second capacitor is coupled to two ends of the inductor 200. Specifically, the third plate 330 may be printed on the fourth dielectric film layer through a printing process.

S800: a fifth dielectric film layer is stacked on the fourth dielectric film layer and covers at least the third electrode plate 330. Specifically, the fifth dielectric film layer is a blank dielectric film. In some embodiments, the fifth dielectric film completely covers the third pole plate 330.

S900: a fourth polar plate 340 is disposed at a side of the fifth dielectric film layer facing away from the fourth dielectric film layer, and a third capacitor is formed between the fourth polar plate 340 and the third polar plate 330, one end of the third capacitor is connected to the output end of the inductor 200, and the other end is grounded. Specifically, the fourth plate 340 may be printed on the fifth dielectric film layer through a printing process.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.

The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims (10)

1. A filter structure, comprising:

the ceramic substrate is provided with an input end electrode and an output end electrode, the input end electrode is used for being connected with signal waves, and the output end electrode is used for outputting the signal waves; wherein the output end electrode and the input end electrode are arranged at opposite intervals;

the inductance piece is of a sheet structure, is arranged in the ceramic matrix, spans between the input end electrode and the output end electrode and is electrically connected with the input end electrode and the output end electrode;

the capacitor piece is arranged in the ceramic substrate and comprises a first polar plate and a second polar plate which are oppositely arranged at intervals, a first capacitor is formed between the first polar plate and the second polar plate, and the first polar plate and the second polar plate are stacked on the inductor piece;

the ceramic substrate is further provided with a grounding end electrode, and the first polar plate and the second polar plate are connected between any two of the input end electrode, the output end electrode and the grounding end electrode, so that the first capacitor is electrically connected with the inductance element.

2. The filter structure of claim 1, wherein the capacitive element further comprises a third plate disposed in spaced relation relative to the second plate on a side thereof facing away from the first plate, the third plate and the second plate forming a second capacitance therebetween;

the first electrode plate is electrically connected with the grounding end electrode, the second electrode plate is electrically connected with the input end electrode, the third electrode plate is electrically connected with the output end electrode, so that the first capacitor is grounded, and the second capacitor and the inductance element form a resonance structure.

3. The filter structure of claim 2, wherein the capacitive element further comprises a fourth plate disposed in relatively spaced relation to a side of the third plate facing away from the second plate, a third capacitance being disposed between the fourth plate and the third plate;

the fourth polar plate is electrically connected with the grounding terminal electrode so as to enable the third capacitor to be grounded.

4. A filter structure according to claim 3, wherein the ground electrode is arranged between the input electrode and the output electrode;

the first polar plate is provided with a first protruding part, and the first protruding part is connected with the grounding terminal electrode; and/or a second protruding part is arranged on the fourth polar plate, and the second protruding part is connected with the grounding terminal electrode.

5. The filtering structure of claim 4, wherein the ground electrode comprises a first sub-port and a second sub-port; the first sub-port and the second sub-port are respectively arranged on two sides of the first polar plate, the number of the first protruding parts is two, one of the two first protruding parts is connected with the first sub-port, and the other is connected with the second sub-port;

and/or the first sub-port and the second sub-port are respectively arranged at two sides of the fourth polar plate, the number of the second protruding parts is two, one of the two second protruding parts is connected with the first sub-port, and the other is connected with the second sub-port.

6. A filter structure according to claim 3, wherein the first capacitor has the same capacitance value as the third capacitor.

7. The filtering structure of claim 1, wherein the inductor member has a bent section bent in a first plane, the bent section having a first sub-section and a second sub-section disposed adjacent to each other, a current direction of the first sub-section being opposite to a current direction of the second sub-section; wherein the first plane is parallel to the first polar plate and/or the second polar plate.

8. The filter structure according to claim 7, wherein the inductance component has a lead-in section and a lead-out section provided at both ends of the bending section, one end of the lead-in section facing away from the bending section is connected to the input terminal electrode, and one end of the lead-out section facing away from the bending section is connected to the output terminal electrode;

wherein the width of the introducing section in the current flow direction is larger than the width of the bending section in the current flow direction; and/or the width of the leading-out section in the current flow direction is larger than the width of the bending section in the current flow direction.

9. A method for producing a filter structure according to any one of claims 1 to 8, comprising:

providing a first dielectric film layer, and arranging a sensing element on the first dielectric film layer;

a second dielectric film layer is overlapped on the first dielectric film layer and at least partially covers the inductance component;

a first polar plate is arranged on one side of the second dielectric film layer, which is away from the first dielectric film layer;

a third dielectric film layer is overlapped on the second dielectric film layer and at least partially covers the first polar plate;

a second polar plate is arranged on one side of the third dielectric film layer, which is away from the second dielectric film layer; and a first capacitor is formed between the first polar plate and the second polar plate, and the first capacitor is electrically connected with the inductance element.

10. The method for manufacturing a filter structure according to claim 9, wherein after the step of disposing the second electrode plate on a side of the third dielectric film layer facing away from the second dielectric film layer, the method for manufacturing a filter structure further comprises:

a fourth dielectric film layer is overlapped on the third dielectric film layer and at least covers the second polar plate;

a third polar plate is arranged on one side, away from the third dielectric film layer, of the fourth dielectric film layer, a second capacitor is formed between the third polar plate and the second polar plate, and the second capacitor is coupled to two ends of the inductance element;

a fifth dielectric film layer is overlapped on the fourth dielectric film layer and at least covers the third polar plate;

and a fourth polar plate is arranged on one side of the fifth dielectric film layer, which is away from the fourth dielectric film layer, a third capacitor is formed between the fourth polar plate and the third polar plate, one end of the third capacitor is connected with the output end of the inductor, and the other end of the third capacitor is grounded.