阅读说明：本技术 基于低温共烧铁氧体工艺的高通滤波器 (High-pass filter based on low-temperature co-fired ferrite process ) 是由 彭根斋 闫欢 张峰平 彭梓 胡艺缤 于 2021-09-13 设计创作，主要内容包括：本发明公开了一种基于低温共烧铁氧体工艺的高通滤波器,属于射频元器件领域,包括腔体和盖板,所述腔体内设置有基板、电感器和电容器,所述基板为多层低温共烧铁氧体基板,所述电感器集成于所述基本内部,所述电容器采用分立元件内埋于所述腔体内；本发明采用LC结构原理设计Chebyshev I型高通滤波器,整体采用立方体开腔结构,将电感器集成于基板内部,电容器采用分立元件内埋于腔体中,成功实现了工作在1MHz～10MHz、截止频率为1MHz、体积为8.2×8.2×2.8mm??的高通滤波器；实现了无源高通滤波器的微型化及可靠性提高,对雷达系统、机载和弹载的通信系统性能的实现和提高具有重要作用,也符合通信系统更轻、更小、更便携、更好性能的发展方向。(The invention discloses a high-pass filter based on a low-temperature co-fired ferrite process, which belongs to the field of radio frequency components and parts and comprises a cavity and a cover plate, wherein a substrate, an inductor and a capacitor are arranged in the cavity, the substrate is a multilayer low-temperature co-fired ferrite substrate, the inductor is integrated in the basic interior, and the capacitor is embedded in the cavity by adopting discrete components; the Chebyshev I-type high-pass filter is designed by adopting an LC structure principle, a cubic open cavity structure is integrally adopted, the inductor is integrated in the substrate, the capacitor is embedded in the cavity by adopting discrete elements, and the high-pass filter which works at 1 MHz-10 MHz, has the cut-off frequency of 1MHz and is obtained by carrying out thin-film evaporation and high-frequency evaporation on the high-pass filter and carrying out thin-film evaporation and high-frequency evaporation on the high-pass filter; the miniaturization and reliability improvement of the passive high-pass filter are realized, the method has an important effect on realizing and improving the performance of a radar system, an airborne communication system and a missile-borne communication system, and the development direction of the communication system, which is lighter, smaller, more portable and better in performance, is also met.)

1. The utility model provides a high pass filter based on ferrite technology is burnt to low temperature, include the cavity with the apron of cavity top, be provided with base plate, inductor and condenser in the cavity, its characterized in that: the substrate is a multilayer low-temperature co-fired ferrite substrate, the inductor is integrated in the substrate, and the capacitor is embedded in the cavity by adopting discrete components.

2. The high-pass filter based on the low-temperature co-fired ferrite process as claimed in claim 1, wherein: the number of the base plates is 60, wherein the number of the slotting layers is 24, the number of the upper covering layers is 12, the number of the coil layers is 9-12, and the number of the lower covering layers is 12.

3. The high-pass filter based on the low-temperature co-fired ferrite process as claimed in claim 1, wherein: five inductors are respectively L1, L2, L3, L4 and L5, wherein the L1, the L2, the L4 and the L5 are located at four vertexes, the L3 is located at a middle position, and the L1, the L2, the L4 and the L5 are distributed around the L3 in a central mode and are interconnected with the top-layer circuit of the substrate.

4. The high-pass filter based on the low-temperature co-fired ferrite process as claimed in claim 3, wherein: the L1 and the L5 are symmetrically distributed, the coil structure is the same, and 12 layers of coils are arranged; l2 and L4 are distributed oppositely, the coil structure is the same, and the coil is provided with 11 layers; the L3 coil was set up in 9 layers.

5. The high-pass filter based on the low-temperature co-fired ferrite process as claimed in claim 3, wherein: the L1, L2, L4 and L5 are sequentially 5.5mm apart.

6. The high-pass filter based on the low-temperature co-fired ferrite process as claimed in claim 3, wherein: the outer diameter of the coil of the inductor is 1.4mm, the outer diameter of the coil is 0.8mm, and the width of the coil is 0.3 mm.

7. The high-pass filter based on the low-temperature co-fired ferrite process as claimed in claim 1, wherein: the capacitor is embedded in the cavity in a patch form.

8. The high-pass filter based on the low-temperature co-fired ferrite process as claimed in claim 1, wherein: the capacitor is a 0603 capacitor, and the material of the capacitor is 2X1 type material.

9. The high-pass filter based on the low-temperature co-fired ferrite process as claimed in claim 1, wherein: the capacitor and the inductor are electrically connected through a printed circuit pattern.

10. The high-pass filter based on the low-temperature co-fired ferrite process as claimed in claim 1, wherein: the cover plate is a metal cover plate.

Technical Field

The invention relates to the field of radio frequency components, which is mainly applied to the fields of communication, radar, navigation, electronic countermeasure and the like and is used as a high-pass filter based on a low-temperature co-fired ferrite process for filtering signals between a receiving module and a rear-stage module.

Background

Aiming at a traditional high-pass filter working at 1 MHz-10 MHz and with the cut-off frequency of 1MHz, compared with a Butterworth filter, the ChebyshevI type filter has the equal ripple fluctuation characteristic in a pass band, and monotonically decreases in a stop band and has larger attenuation characteristic; meanwhile, the higher the order, the greater the steepness of the transition zone, and the transfer function has no zero point. The traditional passive high-pass filter is usually realized by mounting a plurality of discrete inductors, capacitors and other elements on a circuit substrate, but the high filtering performance and the miniaturization requirements of the high-pass filter are difficult to be considered. Fig. 1 is a schematic diagram of a conventional Chebyshev type I high-pass filter circuit.

The technical problems and disadvantages of the conventional high-pass filter are mainly reflected in the following two aspects:

1. the traditional high-pass filter design is characterized in that a plurality of discrete inductors and capacitors are mounted on a circuit substrate, and the purpose of high-pass filtering is realized through multi-stage LC resonance, so that the high-pass filter occupies a large volume on a circuit board, a plurality of welding elements are provided, and particularly, the high-pass filter design with low-frequency-band work, harsh filtering characteristics and high reliability requirements is large in inductance/capacitance value, complex and difficult to realize by adopting a thin-film process integrated design, and the miniaturization and high reliability are more difficult to ensure by adopting PCB mounting;

2. the traditional high-pass filter is limited by the influence of various factors such as element processing technology, reliability and the like, and the impedance characteristics of discrete inductors and capacitor elements need to be adjusted and optimized for multiple times, so that the high-pass filtering performance change caused by the batch difference of capacitors and inductors and the welding process error is avoided, and the batch production efficiency is low.

Disclosure of Invention

The invention aims to provide a high-pass filter based on a low-temperature co-fired ferrite process to solve the problems.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a high-pass filter based on a low-temperature co-fired ferrite process comprises a cavity body and a cover plate above the cavity body, wherein a substrate, an inductor and a capacitor are arranged in the cavity body, the substrate is a multilayer low-temperature co-fired ferrite substrate, the inductor is integrated in the substrate, and the capacitor is embedded in the cavity body by adopting discrete components.

As a preferred technical scheme: the number of the substrate is 60, wherein the slotted layer is 24, the upper covering layer is 12, the coil layer is 9-12, and the lower covering layer is 12.

As a preferred technical scheme: five inductors are respectively L1, L2, L3, L4 and L5, wherein the L1, the L2, the L4 and the L5 are located at four vertexes, the L3 is located at a middle position, and the L1, the L2, the L4 and the L5 are distributed around the L3 in a central mode and are interconnected with the top-layer circuit of the substrate.

As a further preferable technical scheme: the L1 and the L5 are symmetrically distributed, the coil structure is the same, and 12 layers of coils are arranged; l2 and L4 are distributed oppositely, the coil structure is the same, and the coil is provided with 11 layers; the L3 coil was set up in 9 layers.

As a further preferable technical scheme: the L1, L2, L4 and L5 are sequentially 5.5mm apart.

As a further preferable technical scheme: the outer diameter of the coil of the inductor is 1.4mm, the outer diameter of the coil is 0.8mm, and the width of the coil is 0.3 mm.

It should be noted that: the parameters such as the number of basic layers, the number of inductors and the like of the high-pass filter based on the low-temperature co-fired ferrite process are only preferred choices, and the invention can be realized by adopting other values, specifically:

the overall circuit topology structure is shown in FIG. 3, the inductance values of the inductors L1-L5 are 1-10 muH, and the capacitance values C1-C6 are 1-10 nF, which can be completed by adopting the design method and steps of the invention;

the high-pass filter can be designed into 3, 5, 7, 9, 11 and 13 stages; the more the order, the stronger the out-of-band rejection and the greater the in-band insertion loss, but the number of corresponding elements is increased, which leads to the problems of increased difficulty of the integration process, increased integral volume after integration, mutual coupling influence among a plurality of inductors and the like;

the number of substrate stack layers may be between 48-60 layers. The upper covering layer and the lower covering layer are mainly used as magnetic circuit design layers and can be adjusted to optimize the characteristics of mutual influence between the magnetic circuit of the inductor and the capacitor, mutual coupling among a plurality of inductors and the like; wherein, the upper covering layer can be adjusted within the range of 0-12 layers, and the lower covering layer can be adjusted within the range of 0-12 layers; the upper covering layer and the lower covering layer are too few, so that parameters such as leakage inductance and mutual inductance of the inductor can be influenced, and the performance of the filter is further influenced, so that the upper covering layer and the lower covering layer are more and better, but the upper covering layer and the lower covering layer are more and the process preparation difficulty of the integrated substrate can be increased, and therefore, a compromise design is also needed;

the slotting layer can be adjusted within the range of 1-24 layers, and the cover plate can be added to the slotting layer, so that the patch capacitor is sealed in the slot, and the deeper the slotting layer is, the more the number of layers is, the deeper the slot is; the proper number of layers can ensure that the cover plate can seal the surface-mounted capacitor, meanwhile, the cover plate can not touch the capacitor after being packaged, and the filter has moderate volume;

the number of coil design layers can be adjusted within the range of 1-24 layers, the more the number of coil design layers is, the larger the number of coil turns is, and the larger the inductance value of the integrated inductor is;

the LC filtering order of the optional filter is 9 orders, namely 4 inductors and 5 capacitors are integrated. The capacitance value changes; meanwhile, the space distribution structure of the integrated inductor, the inductance value of the integrated inductor and the layer number of the integrated windings are changed, and the size of the substrate can be correspondingly reduced due to the fact that the number of filter elements is reduced. The integration scheme adopts the design method flow of the invention, and can complete the design and the preparation.

As a preferred technical scheme: the capacitor is embedded in the cavity in a patch form. I.e. the patch capacitance is selected.

As a preferred technical scheme: the capacitor is a 0603 capacitor, and the material of the capacitor is 2X1 type material.

A large number of tests prove that the inductor is developed by adopting a substrate integration process, the capacitor performance (Q value and temperature characteristic) is poor along with the reduction of the size of the chip capacitor, the miniaturization requirement of the filter is met by comprehensively considering capacitor selection 0603 packaging, the capacitor material is made of a 2X1 type material with good temperature characteristic, the capacity value is changed by 10% between-50 ℃ and + 85 ℃, the frequency impedance characteristic is good, the self-resonant frequency point is 1-10 MHz, and the design requirement of the filter is met.

As a preferred technical scheme: the capacitor and the inductor are electrically connected through a printed circuit pattern.

As a preferred technical scheme: the cover plate is a metal cover plate.

The inductor and the circuit wiring of the invention are preferably realized by printing patterns and upper and lower through holes, the discrete capacitor is preferably embedded in the cavity in a patch form, the discrete capacitor is electrically connected with the inductor in the substrate by the printing patterns, a simulation design method is used, a proper ferrite substrate material is selected, the inductor can reach the mu H level easily, and finally, the top end of the cavity is sealed by a metal cover plate; the number of discrete elements of a circuit is greatly reduced, a passive LC structure principle is selected to design a Chebyshev I-type high-pass filter, an Ansoft-Designer software is adopted to design a circuit topological structure, and an Ansoft-Maxwell software inductor three-dimensional structure is combined to carry out electromagnetic simulation;

the high-pass filter based on the low-temperature co-fired ferrite process adopts multilayer low-temperature co-fired ferrite ceramics as a substrate, selects an LC structure principle to design a Chebyshev I-type high-pass filter, integrally adopts a cubic open cavity structure, integrates an inductor inside the substrate, adopts discrete components to embed the capacitor in a cavity, and successfully realizes the high-pass filter which works at 1 MHz-10 MHz, has a cut-off frequency of 1MHz and a volume of 8.2 x 2.8mm in the top-down power. The high-pass filter realizes the miniaturization and reliability improvement of the passive high-pass filter, plays an important role in realizing and improving the performance of a radar system, an airborne communication system and a missile-borne communication system, accords with the development direction of lighter, smaller, more portable and better performance of the communication system, and has extremely important significance in high performance, low cost, high reliability and miniaturization.

Compared with the prior art, the invention has the advantages that: the design method of the high-pass filter based on the low-temperature co-fired ferrite process is essentially different from the traditional high-pass filter working at a low frequency band, the whole high-pass filter adopts a cubic open cavity structure, the inductor is integrated in the substrate by adopting the low-temperature co-fired ferrite process, the capacitor is embedded in the cavity by adopting discrete components, and the cover plate is used for integrated packaging, so that the number of discrete components of a circuit is greatly reduced, before improvement, the discrete capacitor 6 is only surface-mounted with the discrete inductor 5, and after improvement, the discrete capacitor 6 is only surface-mounted; the inductor is integrated in the substrate, and the number of the surface mounted inductors is 0, so that the high-pass filter solves the problems of large volume, multiple discrete elements, low integration level and the like of the traditional high-pass filter, simplifies the welding process of devices, and improves the batch production level.

Drawings

FIG. 1 is a schematic diagram of a conventional Chebyshev type I high pass filter circuit;

fig. 2 is a schematic diagram of a high-pass filter circuit according to embodiment 1 of the present invention;

FIG. 3 is an integrated structure diagram of an inductor in a low temperature co-fired ferrite substrate in embodiment 1 of the present invention;

FIG. 4 is a laminated structure of a substrate in accordance with embodiment 1 of the present invention;

FIG. 5 is a diagram showing an overall structure of a filter according to embodiment 1 of the present invention;

FIG. 6 is a top integrated bonding pad circuit diagram of embodiment 1 of the present invention;

FIG. 7 is an inductor winding design layout;

FIG. 8 is a circuit interlayer interconnection diagram according to embodiment 1 of the present invention;

FIG. 9 is a schematic view of a multi-point common layout of an underlying substrate in accordance with embodiment 1 of the present invention;

FIG. 10 is a diagram of a surface mount pad on the back side of the bottom layer in accordance with embodiment 1 of the present invention;

FIG. 11 is a diagram of a dielectric paste covering a surface of a conductor in accordance with example 1 of the present invention;

fig. 12 is a high pass filter outline dimension chart based on LTCF process in embodiment 1 of the present invention.

In the figure, 1, a grooved layer; 2. an upper cladding layer; 3. a coil layer; 4. a lower cover layer; 5. a chip capacitor; 6. an inductance.

Detailed Description

The invention will be further explained with reference to the drawings.

Example 1:

a high-pass filter based on a low-temperature co-fired ferrite process is disclosed, wherein a passive LC structure principle is selected to design a Chebyshev I-type high-pass filter, Ansoft-Designer software is adopted to design a circuit topological structure, and an Ansoft-Maxwell software inductor three-dimensional structure is combined to perform electromagnetic simulation.

Designing a circuit topological structure: according to the technical indexes and the miniaturization purpose of the high-pass filter, the design idea of a Chebyshev I filter is adopted, LC parameters are designed and optimized by combining Ansoft-Designer software, and the topological structure design is completed by referring to the selection rule of discrete component values. And through multiple simulation iterations of the high-pass filter circuit, the LC filtering order of the filter is determined to be 11 orders, the inductance values L1-L5 are 1-10 muH, and the capacitance values C1-C6 are 1-10 nF.

In the embodiment, a topological structure is selected as shown in fig. 2, a capacitor is realized by adopting a mode of embedding a discrete chip element in a cavity, and an inductor is realized by adopting a mode of integrating the discrete chip element in a low-temperature co-fired ferrite substrate;

designing the low-temperature co-fired ferrite substrate integrated inductor: based on the design of a circuit topological structure, the design method of a reference chip inductor is considered in the simulation of a magnetic circuit and the calculation of magnetic flux density. A magnetic circuit design is carried out by adopting a finite element analysis method, the principle is that a calculation space adopts a planning grid mode, magnetic fields on boundaries are assumed to be parallel, and magnetic field distribution is calculated through a Maxwell equation. The simulated inductor core was a ferrite NiZn-based ferrite material with relative permeability measured from a ferrite standard ring core made by low temperature co-firing. The method comprises the steps of establishing a structural model of the integrated inductor by using Ansoft-Maxwell software, inputting data such as ferrite material magnetic permeability, coil turns, outer diameter, inner diameter, wire width, thickness and ferrite basement membrane thickness, establishing a magnetic circuit model, obtaining a magnetic circuit simulation diagram and magnetic flux density, calculating inductance and magnetic leakage flux, and performing eddy current loss, magnetic hysteresis loss and impedance analysis. And finally, determining the basic space structure of the high-pass filter according to the technical indexes of the high-pass filter and the design target of the structure and the magnetic circuit by combining the calculation results of Ansoft-Designer and Ansoft-Maxwell simulation software, and then carrying out parametric analysis on the generated structure model to optimize the structure design scheme.

The embodiment adopts an inductor integrated structure in a low-temperature co-fired ferrite substrate as shown in FIG. 3;

the low-temperature co-fired ferrite multilayer lamination integrated inductor structure comprises: in the multilayer chip type laminated integrated inductor, a ferrite magnetic film (a magnetic core part) and a coil are completely integrated, the magnetic core and the coil are very close to each other, and the magnetic core and the coil have similar low magnetic resistance. Since the magnetic flux is selected to have the lowest reluctance, the magnetic flux does not pass through other coil loops having higher reluctance, and thus the magnetic flux that cannot be effectively coupled with the other coil loops is leakage flux. On the other hand, the relative positions and distances among the coils also cause the difference of self inductance and mutual inductance value, so that the inductance integrated in the substrate deviates from the theoretical value of the discrete inductance to a certain extent, and the filtering parameters of the filter are further changed.

To sum up the design difficulties in two aspects, the present embodiment proposes a solution from three aspects:

(1) circuit topology design

In order to effectively control the mutual inductance influence of an inductance value, establish a multi-winding inductance model and analyze the influence of parasitic parameters among windings, the invention designs the performance parameters of a filter based on a Chebyshev I-type high-pass filter principle method and combined with an Ansoft-Designer software simulation method, and a circuit topological structure with a symmetrical structure is selected as shown in figure 2, so that the inductance value and the capacitance value can meet the following relations:

through a large number of experimental argumentations, the inductor is developed by adopting a substrate integration process, the capacitor performance (Q value and temperature characteristic) is poor along with the reduction of the volume, the capacitor selection 0603 packaging is comprehensively considered to meet the miniaturization requirement of the filter, the capacitor material is made of a 2X1 type material with good temperature characteristic, the frequency impedance characteristic is good within 10% of the capacity value change between minus 50 ℃ and plus 85 ℃, the self-resonant frequency point is 1-10 MHz and far away from 1MHz, and the design requirement of the filter is met;

(2) integrated inductor spatial position design

The method is based on an electromagnetic field theory, combines the integral design requirement of a high-pass filter, adopts Ansoft-Maxwell simulation software, and simulates and outputs the self-inductance and mutual-inductance values of all inductance windings, and the magnetic induction intensity vector diagram and the cloud diagram of all structures aiming at different integrated structures; judging the coupling influence among the windings by analyzing the change percentage of the mutual inductance value relative to the self-inductance; and analyzing the leakage inductance of each winding by analyzing a magnetic induction intensity vector diagram and a cloud diagram.

Simulation design:

the integrated parameters of the substrate are designed by adopting Maxwell software 3D simulation, 5 integrated inductors (L1-L5) are connected in a Z shape, coils at four vertex points of a square substrate are distributed around a coil at the middle position in a central symmetry manner and are interconnected with a circuit at the top layer of the substrate, the integrated inductors are designed by adopting silver paste conductors, the interlayer design is interconnected by adopting upper and lower through holes, and the layers are internally realized by adopting printing screen printing; the design mainly aims at the parameters of the radius of a winding, the wire diameter of the winding, the relative position of the winding, the number of winding layers, the design of an insulating medium, the design of the number of covering layers, the setting of a magnetic material and the like to carry out comparison simulation and optimization model, and establish a simulation model;

through repeated iterative optimization, the size of the outer frame of the integrated substrate is 8.5 multiplied by 8.5mm, and the substrate material is selected from the low-temperature co-fired ferrite 300 type soft magnetic material developed by the applicant (specifically, the invention patent is wide-temperature nickel-zinc low-temperature co-fired ferrite material for high-power multilayer chip ferrite devices and the preparation method; patent No. 201610260375.0); the total number of the substrates is 60, wherein the number of the slotted layers 1 is 24, the number of the slotted layers 1 is 12, the number of the upper covering layers 2 is 9-12, the number of the coil layers 3 is provided with an inductor 6, and the number of the lower covering layers 4 is 12; the laminated structure of the substrate is shown in fig. 4, and the whole structure of the filter is shown in fig. 5;

in the embodiment, the outer diameter of the coil is 1.4mm, the outer diameter of the coil is 0.8mm, and the width of the coil is 0.3 mm; the L3 inductor is integrated at the origin of the space coordinate, and the coils are provided with 9 layers; the L1 and the L5 are symmetrically distributed, the coil structure is the same, and the coil is designed into 12 layers; l2 and L4 are symmetrically distributed, the coil structure is the same, and the coils are arranged in 11 layers; coil arrangement of L3 9 layers; l1, L2, L4 and L5 are sequentially separated by 5.5 mm;

a magnetic field cloud chart is simulated by adopting the model of FIG. 4, and a simulation output inductance value matrix is shown in Table 1;

TABLE 1 output integrated winding simulation inductance matrix (Unit uH)

According to a simulation magnetic induction intensity vector diagram, a cloud diagram and an output inductance matrix, a filter magnetic field of integrated inductance mainly restrains magnetic flux through a winding, and the self-inductance of an inductor is large; the magnetic field distribution area is more regular near the coil, the magnetic field distribution inside the coil is more uniform, and the magnetic flux density is higher; the magnetic field distribution near the coil has a correlation with the number of turns of the coil, namely as the number of turns of the coil increases, the magnetic flux density near the coil also increases; the magnetic field distribution inside the coil is more uniform, and the magnetic flux density is higher; with increasing distance, the magnetic flux density outside the coil gradually decreases, and the mutual coupling between different inductors is less than 1%. The combination of simulation shows that the self-inductance and mutual inductance of the inductor are less influenced by covering the printed insulating medium on the winding conductor layer.

Designing and simulating based on a circuit topological structure principle, fully considering the principle of product reliability and circuit performance optimization, interactively finishing the engineering design of a high-pass integrated filter by adopting Maxwell software and AutoCAD software, and mainly improving the overall layout of the filter, a top-layer integrated pad circuit, interconnection among circuit layers, multipoint common grounding of a bottom-layer substrate and the like;

wherein, the capacitor C in the substrate with an open cavity is realized by designing a top integrated bonding pad circuit₁～C₆The surface mounting is carried out, the layout of the pad circuit is shown in figure 6, and the design layout of the inductance winding is shown in figure 7. In order to realize simple and convenient installation of the high-pass filter, 2I/O ports and ground ports of the filter are designed on the bottom layer, and the back surface of the bottom layerThe layout of the surface-mounted bonding pad is shown in fig. 10, three bonding pads have the same size and the same interval, and 2I/O ports are symmetrically distributed around a middle grounding port;

the circuits between different layers in the substrate are interconnected by using through holes, the interconnection layout between the circuit layers is as shown in fig. 8, and according to the circuit design principle, the number of the spacing layers for carrying out interlayer interconnection between the top capacitor bonding pad, the inductor winding and the bottom I/O port is large. Therefore, the interlayer interconnection between the capacitor bonding pad and the inductance winding (or the bottom layer I/O port) is realized by adopting a plurality of groups of vertical via holes, each group of vertical via holes only penetrate through 2-3 layers of low-temperature co-fired ferrite lamination layers, and 1 circuit bonding pad is designed at the same time, so that the reliability of interlayer interconnection is enhanced; in addition, the via and pad design is as far away from the inductor winding as possible. For the integrated inductor, the winding circuits of the adjacent layers are directly and vertically connected through the via holes, and the bonding pads are not required to be designed.

The bottom substrate of the filter adopts a multipoint common ground design, and as shown in fig. 9, a low temperature co-fired ferrite lamination layer near the bottom of the substrate is designed with a mesh structure conductor as a ground layer. The grounding end of the inductance winding can be directly connected with the ground layer through the vertical through hole, so that multipoint common grounding is realized, and circuit noise is suppressed; meanwhile, the heat dissipation area of the conductor with the net structure is large, the reliability of the circuit is improved, and the processing problems of warping, cracking and the like caused by the fact that the conductor is fully covered by the low-temperature co-fired ferrite lamination are effectively avoided.

In addition, in this embodiment, a layout in which the winding conductor layer is covered with the printed insulating medium is also designed, as shown in fig. 11, and is found through simulation analysis and process development: the winding conductor layer is covered with the printed insulating medium, the influence on the self inductance and the mutual inductance of the inductor is small, and the design that the conductor layer is covered with the printed insulating medium is not adopted finally in consideration of the state of the device development process and the development qualification rate.

Finally, the development of the low-temperature co-fired ferrite substrate integrated inductor is completed by depending on a low-temperature co-fired ferrite process platform, and the volume size of the final product is 8.2 x 2.8mm³The patch capacitors C2, C3, C4 and C5 are 2.7nF, and the capacitors C1 and C6 are 4.7 nF; 4.3uH is selected as the winding inductance L3 at the middle position; the four winding inductances L2 and L4 of the substrate near the edge are selected from 4.7uH, L1 andl5 was selected to be 5.4uH, and its outer dimensions are shown in FIG. 12.

Example 2:

key technical index test of products obtained by embodiment

All tests and experiments carried out in this example were carried out under "Standard atmospheric conditions of the experiment" as defined in GJB360A-1996, section 4.1.1.

The high pass filter test port I/O1 (or input port), I/O2 (or output port) were connected to network analyzer test ports 1, 2 for electrical performance measurements, with specific test data as shown in table 2.

TABLE 2 insertion loss vs. voltage standing wave ratio index test (Normal temperature 25 deg.C)

At normal temperature, the passband bandwidth of the filter is 1-10 MHz, the cut-off frequency is 1MHz, the insertion loss is less than 3.1 dB, the stopband attenuation is more than 40 dB (300-500 kHz), the passband fluctuation is less than 2.5 dB, the voltage standing wave ratio is less than 1.4, and all performance indexes meet the design requirements.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.