CN110022133B - Small inductance coupling type adjustable band-pass filter and preparation method thereof - Google Patents
Small inductance coupling type adjustable band-pass filter and preparation method thereof Download PDFInfo
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- CN110022133B CN110022133B CN201910334810.3A CN201910334810A CN110022133B CN 110022133 B CN110022133 B CN 110022133B CN 201910334810 A CN201910334810 A CN 201910334810A CN 110022133 B CN110022133 B CN 110022133B
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- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
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- H—ELECTRICITY
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- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
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Abstract
The invention discloses a small-sized inductance coupling type adjustable band-pass filter, and belongs to the technical field of filters. The structure mainly comprises a shell, an input electrode, an output electrode, a grounding electrode, a three-layer grounding plate, inductors among different layers of the grounding plate and capacitors on the surface of the shell, wherein the grounding plate and the inductors are sintered in a ceramic substrate by adopting a low-temperature co-fired ceramic technology, and the capacitors are attached to the upper surface of the shell. The invention has simple structure, low cost, small volume and good batch consistency, and is prepared by using a low-temperature co-fired ceramic technology; meanwhile, the three layers of grounding plates separate different inductors and capacitors, so that parasitic and resonance caused by unnecessary coupling are avoided, and the filtering accuracy and the quality factor are improved.
Description
Technical Field
The invention belongs to the technical field of filters, and particularly relates to a miniaturized inductance coupling type adjustable band-pass filter.
Background
In recent years, with the rapid development of miniaturization of mobile communication, satellite communication and defense electronic systems, high performance, low cost and miniaturization have become the development direction of the microwave/radio frequency field at present, and higher requirements are put forward on the performance, size, reliability and cost of a microwave filter. The communication countermeasure system needs to process signals under a complex information environment, and needs a filter to realize the selection of the signals. The filter is mainly used for separating signals and suppressing interference, and the most extensive and basic application of the filter is. In such applications, the electrically tunable filter allows the desired frequency signals to pass through smoothly, and suppresses the undesired frequencies. The current communication system requires low insertion loss, low in-band fluctuation and high signal selectivity of a filter along with practical requirements, and simultaneously the size of the filter is as small as possible so as to meet the requirements of sensitivity and dynamic range. The electrically tunable filter has the advantages of small volume and wide working frequency band, can well inhibit second-order combined signals, and has wide application prospect.
The band-pass filter needs a large capacitor and a large inductor to form a resonator when working under an ultrashort wave frequency band. In order to meet the miniaturization requirement of the device, the initial method is to adopt a dielectric material with high dielectric constant, high quality factor and low loss to reduce the size of the resonator, thereby reducing the volume of the device. However, the traditional process technology has high cost, complex manufacturing process and poor batch consistency.
Disclosure of Invention
The invention aims to: the utility model provides a miniaturized inductance coupling adjustable band-pass filter, has solved the problem that traditional technology is not technical cost higher, and the preparation technology is complicated, and the batch uniformity is poor under the miniaturized condition.
The technical scheme adopted by the invention is as follows:
a miniaturized inductively coupled tunable bandpass filter comprising: the grounding device comprises a shell, an input electrode and an output electrode which are positioned at two ends of the shell, grounding electrodes positioned at two sides of the shell and a three-layer grounding plate positioned in the shell;
a contact bridge is arranged between the grounding electrodes on the two sides of the shell, and the three layers of grounding plates are all in contact with the grounding electrodes; an inductor La, an inductor Lb and an inductor Ld are arranged between the first layer grounding plate and the second layer grounding plate, an inductor Lc and an inductor Le are arranged between the second layer grounding plate and the third layer grounding plate, and a first welding disc and a second welding disc are arranged on the surface, close to the outer wall of the shell, of the third layer grounding plate;
the input electrode, the inductor La, the inductor Lb, the inductor Ld and the output electrode are sequentially connected in series; a first conductive column is arranged between a connection point of the inductor La and the inductor Lb, one end of the inductor Lc and one end of the first welding disc, and a second conductive column is arranged between a connection point of the inductor Lb and the inductor Ld, one end of the inductor Le and one end of the second welding disc; the other end of the inductor Lc and the other end of the inductor Le are respectively in contact connection with a grounding electrode, the other end of the first welding disc is connected with the grounding electrode after being connected with the capacitor Ca, and the other end of the second welding disc is connected with the grounding electrode after being connected with the capacitor Cb;
and the second layer grounding plate and the third layer grounding plate are respectively provided with a yielding hole for the conductive column to pass through.
Further, the inductor La, the inductor Lb, the inductor Lc, the inductor Ld, and the inductor Le are all spiral inductors, each layer of the spiral inductor is a rectangle or 3/4 rectangle made by winding a metal conductive tape, and the capacitor Ca and the capacitor Cb are all adjustable capacitors;
the inductor La and the inductor Ld are consistent in structure, and the inductor Lc and the inductor Le are completely symmetrical about the Z axis and are mutually coupled.
Further, the shell is made of low-temperature co-fired ceramic, and the inductor and the grounding plate are sintered in the ceramic substrate; the elements including the case, the first bonding pad, the second bonding pad, the capacitor Ca, and the capacitor Cb are packaged with FV1206, and the ground electrode, the input electrode, and the output electrode are exposed.
Furthermore, the shell is in a cuboid shape, and the first layer of grounding plate, the second layer of grounding plate and the third layer of grounding plate are all parallel to the bottom surface of the shell; the input pole and the output pole are both ports of 50 Ω impedance.
A preparation method of a miniaturized inductance coupling type adjustable band-pass filter comprises the following steps:
preparing materials: selecting a ceramic raw material formula to prepare a ceramic material;
casting: preparing the prepared ceramic material into casting slurry, and casting a ceramic substrate;
punching and filling holes: punching partial ceramic substrate to obtain conductive column abdicating holes and inductance connecting holes, and then filling the holes by using metal slurry;
conductor printing: conducting conductor printing by using the ceramic substrate after hole filling to prepare a metal conduction band for forming the spiral inductor, wherein different ceramic substrate layers of the same spiral inductor are connected through the inductor connecting hole after hole filling; conducting conductor printing is carried out by using the ceramic substrate with the conducting post abdicating hole, and a grounding plate metal layer which is not contacted with the conducting post is formed;
laminating: laminating the ceramic substrate printed with the conductor and the ceramic substrate not printed with the conductor according to a design structure to form a spiral inductor and a grounding plate which are arranged in a layered manner;
isostatic pressing: putting the laminated module in water for isostatic pressing so as to tightly press and mold different layers of green ceramic substrates to form a complete filter device;
glue discharging and sintering: placing the module subjected to isostatic pressing in a sintering furnace for glue discharging and sintering;
connecting surface layer components: and connecting the capacitor on the surface layer with the module after binder removal and sintering to obtain the low-temperature co-fired ceramic tunable band-pass filter.
Furthermore, the raw materials of the metal paste and the metal conduction band are silver paste, and the thickness of the printed conductor is 10 +/-1 micron.
Further, in the step of discharging and sintering, when discharging and sintering are carried out in the sintering furnace, the temperature of the sintering furnace is 50 ℃.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
1. the invention adopts low temperature co-fired ceramic, each component is sintered on the ceramic substrate, and the low temperature co-fired ceramic technology can manufacture the circuit substrate with high layer number, and can embed a plurality of passive elements therein, thus being beneficial to improving the assembly density of the circuit and reducing the volume and weight of the device.
2. The invention has simple structure, adopts the low-temperature co-fired ceramic technology, and has simple manufacturing process, good batch consistency and lower cost.
3. The three-layer grounding plate is arranged in the ceramic shell, and the inductance element and the capacitance element are arranged in a layered mode, so that coupling interference between the inductance of different layers and the inductance of other layers and coupling interference between the inductance and the capacitance of other layers are avoided, parasitic and resonance caused by unnecessary coupling between components are reduced, the size of the component is reduced, and meanwhile, the accuracy of the filter is guaranteed.
4. The ceramic material has excellent characteristics of high frequency, high-speed transmission and wide passband. According to different ingredients, the dielectric constant of the ceramic material can be changed in a large range, and a high-conductivity metal material is used as a conductor material in a matched manner, so that the quality factor of a circuit system is improved.
5. The low-temperature co-fired ceramic is sintered at the temperature of about 900 ℃, can meet the requirements of heavy current and high-temperature resistance, has better heat conductivity than a common PCB circuit substrate, greatly optimizes the heat dissipation design of electronic equipment, has high reliability, can be applied to severe environment and prolongs the service life of the electronic equipment.
6. The invention adopts FV1206 package, which is convenient to integrate into the system and weld under the condition of ensuring small volume of the device.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and that for those skilled in the art, other relevant drawings can be obtained according to the drawings without inventive effort, wherein:
FIG. 1 is an overall perspective view of the present invention;
fig. 2 is a perspective view of the inductor, capacitor and conductive post of the present invention;
fig. 3 is a front view structural diagram of the inductor capacitor and the conductive column of the present invention;
FIG. 4 is a perspective view of the inductor and ground electrode of the present invention;
FIG. 5 is a schematic diagram of an oblique view of a capacitor and a ground electrode according to the present invention;
FIG. 6 is a perspective view of the grounding plate and the grounding electrode of the present invention;
fig. 7 is a front view structural diagram of an inductor, a conductive column, a ground plate, an input electrode and an output electrode according to the present invention;
FIG. 8 is a schematic diagram of an equivalent circuit of the filter of the present invention;
FIG. 9 is a flow chart of the filter fabrication of the present invention;
FIG. 10 is a graph of simulation results according to the present invention;
the labels in the figure are: 1-inductor La, 2-inductor Lb, 3-inductor Lc, 4-inductor Ld, 5-inductor Le, 6-first bonding pad, 7-second bonding pad, 8-first conductive post, 9-second conductive post, 10-grounding electrode, 11-contact bridge, 12-capacitor Ca, 13-first layer grounding plate, 14-second grounding plate, 15-third layer grounding plate layer, 16-abdication hole, 17-input electrode, 18-output electrode, 19-shell, 20-capacitor Cb, 21-inductor connection hole.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
It is noted that relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
As shown in fig. 1 to 7, wherein fig. 2 to 7 are detailed views of fig. 1;
a miniaturized inductively coupled tunable bandpass filter comprising: the grounding structure comprises a shell 19, an input electrode 17 and an output electrode 18 which are positioned at two ends of the shell 19, grounding electrodes 10 which are positioned at two sides of the shell 19 and a three-layer grounding plate which is positioned inside the shell 19;
specifically, the housing 19 is formed by sintering low-temperature co-fired ceramic, and has a rectangular shape as a whole, with width and height forming surfaces being two end surfaces of the housing 19, respectively, and length and height forming surfaces being two side surfaces of the housing 19, respectively; an input electrode 17 and an output electrode 18 of the filter are respectively arranged on two end faces of the shell 19, and the two end faces of the shell 19 are wrapped by the input electrode 17 and the output electrode 18; two grounding electrodes 10 are respectively arranged on two side surfaces of the shell 19, the grounding electrodes 10 are in a door-shaped structure, the inner diameter of the grounding electrodes 10 is consistent with the height of the shell 19, and the two grounding electrodes 10 are respectively buckled and embedded in the middle positions of the two sides of the shell 19; the three-layer grounding plate sintered in the ceramic substrate in the shell 19 is respectively a first-layer grounding plate 13, a second-layer grounding plate 14 and a third-layer grounding plate 15, the three-layer grounding plates are all parallel to the bottom surface of the cuboid shell 19, and the three-layer grounding plate divides the inner space of the shell 19 into two parts.
It can be understood that the Low Temperature Co-fired Ceramic (Low Temperature sintered Co-fired Ceramic LTCC) technology is to make Low Temperature sintered Ceramic powder into a green Ceramic tape with precise and compact thickness, to make the required circuit pattern on the green Ceramic tape by using the processes of laser drilling, micro-hole grouting, precise conductor paste printing, etc., and to embed a plurality of passive components (such as Low-capacitance capacitors, resistors, filters, impedance converters, couplers, etc.) into a multilayer Ceramic substrate, and then to laminate them together, and the inner and outer electrodes can be sintered at 900 ℃ to make a three-dimensional high-density circuit without mutual interference, or to make a three-dimensional circuit substrate with built-in passive elements, and to mount ICs and active devices on the surface thereof to make a passive/active integrated functional module, which can further miniaturize and densify the circuit.
A contact bridge 11 is arranged between the two grounding electrodes 10 on the two sides of the shell 19, and the three layers of grounding plates are all in contact with the grounding electrodes 10; an inductor La 1, an inductor Lb 2 and an inductor Ld4 are arranged between the first layer grounding plate 13 and the second layer grounding plate 14, an inductor Lc 3 and an inductor Le 5 are arranged between the second layer grounding plate 14 and the third layer grounding plate 15, and a first welding disc 6 and a second welding disc 7 are arranged on the surface of the outer wall of the shell 19 close to the third layer grounding plate 15;
specifically, the contact bridge 11 is a rectangular metal plate, the width of the contact bridge is consistent with the width of the gate posts of the gate-type grounding electrode 10, the length of the contact bridge is consistent with the distance between the gate posts of the two grounding electrodes 10, the upper surface of the shell 19 is placed between the gate posts of the two grounding electrodes 10, and the two grounding electrodes 10 are connected to form an integral grounding; the three-layer grounding plate is roughly shaped as a rectangular metal plate slightly reduced compared with the bottom surface of the shell 19, the shape of the three-layer grounding plate is different from that of a regular rectangle, the two sides of the grounding plate corresponding to the grounding electrode 10 are protruded, and the protruded parts are in contact connection with the grounding electrodes 10 on the two sides of the shell 19; the inductors are all spiral inductors and are sintered in a ceramic substrate, each layer of each spiral inductor is a rectangle or 3/4 rectangle formed by winding a metal conducting strip with the width of 0.1mm, the structures of the inductor La 7 and the inductor Ld 10 are consistent, and the inductor Lc 9 and the inductor Le 11 are completely symmetrical about the Z axis and are mutually coupled; the capacitor Ca 12 and the capacitor Cb 20 both adopt adjustable capacitors.
The input electrode 17, the inductor La 1, the inductor Lb 2, the inductor Ld4 and the output electrode 18 are sequentially connected in series; a first conductive column 8 is arranged between a connection point of the inductor La 1 and the inductor Lb 2, one end of the inductor Lc 3 and one end of the first welding disc 6, and a second conductive column 9 is arranged between a connection point of the inductor Lb 2 and the inductor Ld4, one end of the inductor Le 5 and one end of the second welding disc 7; the other end of the inductor Lc 3 and the other end of the inductor Le 5 are respectively in contact connection with a grounding electrode 10, the other end of the first welding disc 6 is connected with a capacitor Ca 12 and then connected with the grounding electrode 10, and the other end of the second welding disc 7 is connected with a capacitor Cb 20 and then connected with the grounding electrode 10;
specifically, the filter housing 19 is made of low-temperature co-fired ceramic, the inductor and the ground plate are both formed by winding a metal conduction band printed on a ceramic substrate through a conductor, the inductor La 1, the inductor Lb 2 and the inductor Ld4 are sequentially connected in series when the conductor is printed, the metal conduction band between the inductor La 1 and the inductor Lb 2 is in contact connection with the first conductive pillar 8, and the metal conduction band between the inductor Lb 2 and the inductor Ld4 is in contact connection with the second conductive pillar 9; meanwhile, the metal conduction band starting end of the inductor La 1 is in contact connection with the input electrode 17, and the metal conduction band terminal of the inductor Ld4 is in contact connection with the output electrode 18; the metal conduction band starting end of the inductor Lc 3 is arranged to be circularly sleeved on the first conductive column 8 to be in contact connection with the first conductive column, the metal conduction band terminal of the inductor Lc 3 is arranged to be in contact connection with the grounding electrode 10, the metal conduction band starting end of the inductor Le 5 is arranged to be circularly sleeved on the second conductive column 9 to be in contact connection with the second conductive column, and the metal conduction band terminal of the inductor Le 5 is in contact connection with the grounding electrode 10; the both ends of being connected of first bonding pad 6 and second bonding pad 7 are upper end and lower extreme respectively, and wherein the lower extreme of first bonding pad 6 is connected with first leading electrical pillar 8, and the lower extreme of second bonding pad 7 leads electrical pillar 9 with the second and is connected, and electric capacity Ca 12 is welded to the upper end of first bonding pad 6, and electric capacity Cb 20 is welded to the upper end of second bonding pad 7, and electric capacity Ca 12 and electric capacity Cb 20 other end all are connected with earthing pole 10.
The equivalent circuit is shown in fig. 8, and includes: the input end Pin, the output end Pout, the inductor La 1, the inductor Lb 2, the inductor Lc 3, the inductor Ld4, the inductor Le 5, the capacitor Ca 12, the capacitor Cb 20 and the signal ground GND;
the specific connection relationship is as follows:
the input end Pin, the inductor La 7, the inductor Lb 8, the inductor Ld 10 and the output end Pout are sequentially connected in series, a connection point of the inductor La 7 and the inductor Lb 8 is connected with a signal ground GND through the inductor Lc 9, the inductor Lb 8 and the inductor Ld 10 are connected with the signal ground GND through the inductor Le 11, the capacitor Ca 12 is connected with the inductor Lc 9 in parallel, and the capacitor Cb 20 is connected with the inductor Le 11 in parallel.
The second layer grounding plate 14 and the third layer grounding plate 15 are respectively provided with a yielding hole 16 for the conductive column to pass through;
specifically, the diameter of the conductive column is slightly less than the inner diameter of the abdicating hole 16, and the conductive column penetrates through the space separated by the second layer grounding plate 14 and the third layer grounding plate 15 through the abdicating hole 16, so that the inductance and capacitance between different layers can be conveniently connected.
It can be understood that, since the housing 19 is made of low temperature co-fired ceramic, the ground plate, the inductor, and the conductive post are all sintered in the ceramic substrate inside the housing 19, the capacitor is attached to the upper surface of the housing 19, and the inductor and the capacitor are separated layer by the three-layer ground plate, thereby avoiding unnecessary coupling between the inductor of different layers and the inductor and between the inductor and the capacitor of other layers, generating parasitic or resonant interference, and improving the filtering accuracy and Q value of the filter. Meanwhile, the invention has simple structure, mainly comprises an inductor and a capacitor, is sintered by adopting a low-temperature co-fired ceramic technology, and has convenient manufacture, good batch consistency and lower cost.
The ceramic material has excellent characteristics of high-frequency and high-speed transmission and wide passband, the dielectric constant of the ceramic material can change in a large range according to different ingredients, and a high-conductivity metal material is used as a conductor material in a matching way, so that the quality factor of a circuit system is favorably improved, and the flexibility of circuit design is increased;
moreover, the PCB can adapt to the requirements of large current and high temperature resistance, has better heat conductivity than a common PCB circuit substrate, greatly optimizes the heat dissipation design of electronic equipment, has high reliability, can be applied to severe environment and prolongs the service life of the electronic equipment.
Further, the components including the housing 19, the first bonding pad 6, the second bonding pad 7, the capacitor Ca 12 and the capacitor Cb 20 are packaged by FV1206, and only the ground electrode 10, the input electrode 17 and the output electrode 18 are exposed;
the specific packaging size is 3.2 × 1.6 × 0.94mm, so that the small size and the usability of the device are ensured, and the filter is convenient to weld and integrate in a system; the grounding electrode 10, the input electrode 17 and the output electrode 18 are made of copper materials.
The first layer of grounding plate 13, the second layer of grounding plate 14 and the third layer of grounding plate 15 are all parallel to the bottom surface of the shell 19 to form a multilayer structure, which is beneficial to the layout of inductance elements.
The input electrode 17 and the output electrode 18 are both ports with 50 omega impedance, so that the test is convenient.
The preparation process of the filter of the invention is shown in fig. 9, and the specific preparation method is as follows:
preparing materials: selecting a ceramic raw material formula to prepare a ceramic material;
casting: preparing the prepared ceramic material into casting slurry, and casting a ceramic substrate;
punching and filling: punching a part of the ceramic substrate to obtain conductive column abdicating holes 16 and inductance connecting holes 21, and filling the holes by using metal slurry;
conductor printing: conducting conductor printing by using the ceramic substrate after hole filling to prepare a metal conduction band for forming the spiral inductor, wherein different ceramic substrate layers of the same spiral inductor are connected through an inductor connecting hole 21 after hole filling; conducting printing of conductors is carried out by using the ceramic substrate with the conducting post abdicating hole 16, and a grounding plate metal layer which is not contacted with the conducting post is formed;
laminating: laminating the ceramic substrate printed with the conductor and the ceramic substrate not printed with the conductor according to a designed structure to form a spiral inductor and a grounding plate which are arranged in a layered manner;
isostatic pressing: putting the laminated module in water for isostatic pressing so as to tightly press and mold different layers of green ceramic substrates to form a complete filter device;
glue discharging and sintering: placing the isostatic pressed module in a sintering furnace for glue discharging and sintering;
connecting surface layer components: and connecting the capacitor on the surface layer with the module after binder removal and sintering to obtain the low-temperature co-fired ceramic tunable band-pass filter.
Specifically, after the silver paste is filled in the relief hole 16, a conductive column is formed for connecting devices between different layers; the metal slurry used for filling the holes and the raw material of the metal conduction band used for printing the conductor both adopt silver slurry, and the thickness of the printed metal conduction band is 10 +/-1 micron;
it can be understood that the thickness of the metal conduction band is formed by performing thickness reduction treatment on the pattern of the corresponding printed conductor of each layer of the ceramic substrate, namely the reduced thickness of the ceramic substrate is the conductor printing thickness and corresponds to the thickness of the metal conduction band;
and when the glue is discharged and sintered, the temperature of the sintering furnace is controlled to be 50 ℃.
The filter housing 19 is formed by stacking a plurality of ceramic substrates, and each ceramic substrate is punched, filled and printed with conductors to form a stacked arrangement of a spiral inductor, a ground plate and a conductive column;
for example, the spiral inductor comprises a multilayer structure, wherein a metal conduction band with each layer of rectangular or 3/4 rectangular shape is printed on a ceramic substrate through a conductor, then the multilayer ceramic substrates are stacked, and the rectangular metal conduction bands among the structures of each layer are connected through an inductor connecting hole 21 to form a uniform spiral inductor; the conductor printing of ground plate is for printing whole ceramic substrate surface, has the place of leading electrical pillar and abdication hole 16, and the printing conductor is printed along abdication hole 16 border, does not contact with leading electrical pillar, but ground plate printing conductor extends out and contacts with earthing pole 10 on casing 19 both sides.
The features and properties of the present invention are described in further detail below with reference to examples.
Fig. 10 shows a simulation result chart of the present invention, and the filtering from any point in the range of 250MHz to 400MHz can be realized by changing the size of the variable capacitor. And the filtering precision is high and the quality factor is good.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the scope of the present invention, and any modifications, equivalents and improvements made by those skilled in the art within the spirit and scope of the present invention should be included in the present invention.
Claims (6)
1. A miniaturized inductively coupled tunable bandpass filter, comprising: the grounding device comprises a shell (19), an input electrode (17) and an output electrode (18) which are positioned at two ends of the shell (19), grounding electrodes (10) which are positioned at two sides of the shell (19) and a three-layer grounding plate which is positioned inside the shell (19);
a contact bridge (11) is arranged between the grounding electrodes (10) on the two sides of the shell (19), and the three layers of grounding plates are all in contact with the grounding electrodes (10); an inductor La (1), an inductor Lb (2) and an inductor Ld (4) are arranged between the first layer grounding plate (13) and the second layer grounding plate (14), an inductor Lc (3) and an inductor Le (5) are arranged between the second layer grounding plate (14) and the third layer grounding plate (15), and a first welding disc (6) and a second welding disc (7) are arranged on the surface of the outer wall of the shell (19) close to the third layer grounding plate (15);
the shell (19) is made of low-temperature co-fired ceramic, and the inductor and the grounding plate are sintered in the ceramic substrate; elements including a housing (19), a first bonding pad (6), a second bonding pad (7), a capacitor Ca (12) and a capacitor Cb (20) are packaged by FV1206, and a grounding electrode (10), an input electrode (17) and an output electrode (18) are exposed outside;
an input electrode (17), an inductor La (1), an inductor Lb (2), an inductor Ld (4) and an output electrode (18) are sequentially connected in series; a first conductive column (8) is arranged between a connection point of the inductor La (1) and the inductor Lb (2), one end of the inductor Lc (3) and one end of the first welding disc (6), and a second conductive column (9) is arranged between a connection point of the inductor Lb (2) and the inductor Ld (4), one end of the inductor Le (5) and one end of the second welding disc (7); the other end of the inductor Lc (3) and the other end of the inductor Le (5) are respectively in contact connection with a grounding electrode (10), the other end of the first welding disc (6) is connected with a capacitor Ca (12) and then connected with the grounding electrode (10), and the other end of the second welding disc (7) is connected with a capacitor Cb (20) and then connected with the grounding electrode (10);
and the second layer grounding plate (14) and the third layer grounding plate (15) are respectively provided with a yielding hole (16) for the conductive column to pass through.
2. The miniaturized inductively coupled tunable bandpass filter of claim 1 wherein: the inductor La (1), the inductor Lb (2), the inductor Lc (3), the inductor Ld (4) and the inductor Le (5) are all spiral inductors, each layer of each spiral inductor is a rectangle or 3/4 rectangle formed by winding a metal guide belt, and the capacitor Ca (12) and the capacitor Cb (20) are adjustable capacitors;
the inductor La (1) and the inductor Ld (4) are consistent in structure, and the inductor Lc (3) and the inductor Le (5) are completely symmetrical about the Z axis and are mutually coupled.
3. The miniaturized inductively coupled tunable bandpass filter of claim 1 wherein: the shell (19) is in a cuboid shape, and the first layer of grounding plate (13), the second layer of grounding plate (14) and the third layer of grounding plate (15) are all parallel to the bottom surface of the shell (19);
the input pole (17) and the output pole (18) are both ports with 50 omega impedance.
4. A method for manufacturing a miniaturized inductively coupled tunable bandpass filter according to any one of claims 1 to 3, wherein the manufacturing step comprises:
preparing materials: selecting a ceramic raw material formula to prepare a ceramic material;
casting: preparing the prepared ceramic material into casting slurry, and casting a ceramic substrate;
punching and filling holes: punching partial ceramic substrate to obtain a conductive column abdicating hole (16) and an inductance connecting hole (21), and filling the hole by using metal slurry;
conductor printing: conducting conductor printing by using the ceramic substrate after hole filling to prepare a metal conduction band for forming the spiral inductor, wherein different ceramic substrate layers of the same spiral inductor are connected through an inductor connecting hole (21) after hole filling; conducting conductor printing is carried out by using a ceramic substrate with conducting post abdicating holes (16) to form a grounding plate metal layer which is not contacted with the conducting posts;
laminating: laminating the ceramic substrate printed with the conductor and the ceramic substrate not printed with the conductor according to a design structure to form a spiral inductor and a grounding plate which are arranged in a layered manner;
isostatic pressing: putting the laminated module in water for isostatic pressing so as to tightly press and mold different layers of green ceramic substrates to form a complete filter device;
glue discharging and sintering: placing the isostatic pressed module in a sintering furnace for glue discharging and sintering;
connecting surface layer components: and connecting the capacitor on the surface layer with the module after binder removal and sintering to obtain the low-temperature co-fired ceramic adjustable band-pass filter.
5. The method as claimed in claim 4, wherein the tunable bandpass filter comprises: the raw materials of the metal paste and the metal conduction band are silver paste, and the thickness of the printed conductor is 10 +/-1 micrometers.
6. The method as claimed in claim 4, wherein the tunable bandpass filter of miniaturized inductive coupling type comprises: in the step of discharging and sintering, when discharging and sintering are carried out in a sintering furnace, the temperature of the sintering furnace is 50 ℃.
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| CN115514335A (en) * | 2022-10-10 | 2022-12-23 | 深圳威迈斯新能源股份有限公司 | Multilayer structure filter and vehicle mounted power supply DCDC conversion equipment |
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