Low-capacity feed-through ceramic dielectric capacitor based on high-dielectric-constant ceramic dielectric
By employing a high dielectric constant ceramic substrate and controlling the spacing between external electrodes, and using parasitic capacitance to replace the internal electrodes, the problems of high cost and large size of traditional low-capacity feedthrough ceramic capacitors are solved, realizing a low-cost and miniaturized low-capacity capacitor design.
Patent Information
- Application Number
- CN202520060024.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-10
- Publication Date
- 2026-01-16
- Estimated Expiration
- 2035-01-10
AI Technical Summary
Traditional low-capacity feedthrough ceramic capacitors use low dielectric constant ceramic substrates, resulting in high product costs, large thickness and volume. In addition, the need for multiple layers of external and internal electrodes increases costs and volume.
A high dielectric constant ceramic substrate is used, the internal electrode is removed, and the parasitic capacitance between the second end electrode and the first end electrode and between the second end electrode and the external electrode is used as the capacitance. The spacing between the external electrode and the through hole and between adjacent external electrodes is controlled within a specific range to meet the low capacitance requirement.
It significantly reduces the cost of dielectrics and products, reduces silver-palladium alloy materials and processing steps, and reduces product thickness and volume, while maintaining capacitance accuracy within ±10%, meeting the requirements of high-frequency filtering applications.
Smart Images
Figure CN223809020U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a through-hole ceramic dielectric capacitor, especially to a low-capacitance through-hole ceramic dielectric capacitor based on high dielectric constant ceramic medium. BACKGROUND
[0002] The through-hole ceramic dielectric capacitor is a kind of capacitor with ceramic material as medium, generally multilayer structure of sheet type, metal layer is arranged on the outer peripheral wall of ceramic substrate and the hole wall of through-hole through hole respectively as end electrode, multilayer outer electrode and inner electrode are arranged in the ceramic substrate, each layer of outer electrode is connected with the metal layer on the outer peripheral wall of ceramic substrate, each layer of inner electrode is connected with the metal layer on the hole wall of through-hole through hole of ceramic substrate, multilayer outer electrode and multilayer inner electrode are staggered, and an outer electrode and an inner electrode of adjacent one constitute a capacitor unit, each through-hole through hole corresponds a sub capacitor, and the capacitance of each sub capacitor is the sum of the capacitance of multiple capacitor units corresponding to the through-hole through hole. In practical application, most of the sheet type through-hole ceramic dielectric capacitors are provided with multiple through-hole through holes, form array structure composed of multiple sub capacitors, also called array plate type through-hole ceramic dielectric capacitor, and are mostly used in filter.
[0003] The cut-off frequency of capacitor filter is directly related to capacitance, and the greater the capacitance, the lower the cut-off frequency of capacitor filter, so the capacitance of through-hole ceramic dielectric capacitor is generally designed according to the working signal frequency and interference signal frequency. The signal frequency transmitted by some filters is relatively high (100kHz-10MHz), and the through-hole ceramic dielectric capacitor cannot affect the transmission of normal working signal, so the capacitance of capacitor in the filter is relatively low, all less than 1000pF, mainly distributed in 200pF-800pF.
[0004] The ceramic medium used for through-hole ceramic dielectric capacitor includes high dielectric constant ceramic (generally two or three types of ceramic) and low dielectric constant ceramic (generally one type of ceramic), and the low dielectric constant of low dielectric constant ceramic is generally less than 100, and the price is relatively expensive. The dielectric constant of the most commonly used high dielectric constant ceramic is generally about 3000, and the price is relatively cheap. The capacitance of through-hole ceramic dielectric capacitor is proportional to the dielectric constant of ceramic medium, so the high-capacitance (here, the capacitance is the same as the capacitance, the same below) through-hole ceramic dielectric capacitor generally selects high dielectric constant ceramic as medium, and the low-capacitance through-hole ceramic dielectric capacitor generally selects low dielectric constant ceramic as medium.
[0005] For example, Figure 1As shown, the conventional low-capacity through-hole ceramic dielectric capacitor adopts a low dielectric constant ceramic substrate 1, a through-hole 2 (generally multiple, four in the figure) is arranged on the low dielectric constant ceramic substrate 1, a metal layer is arranged on the outer peripheral wall of the low dielectric constant ceramic substrate 1 and serves as a first end electrode 3 (generally grounded in a filter), a metal layer is arranged on the hole wall of the through-hole 2 and serves as a second end electrode 6 (generally used for the power line or signal line requiring filtering to pass through and closely contact in the filter), an outer electrode 4 and an inner electrode 5 (one 4 outer electrode and one inner electrode 5 form a layer, generally multiple layers of structure) are arranged in the low dielectric constant ceramic substrate 1, each layer of the outer electrode 4 is connected with the first end electrode 3, each layer of the inner electrode 5 is connected with the second end electrode 6, the multiple layers of the outer electrode 4 and the multiple layers of the inner electrode 5 are staggered, and the outer electrode 4 and the inner electrode 5 partially overlap in the thickness direction of the low dielectric constant ceramic substrate 1.
[0006] The conventional low-capacity through-hole ceramic dielectric capacitor has the following defects: the low dielectric constant ceramic substrate is used as the medium, which leads to high product price and increases product cost; the low dielectric constant ceramic substrate has small dielectric constant, so a large number of outer electrodes and inner electrodes are required to achieve corresponding capacitance, which increases product thickness and volume to some extent, and the outer electrodes and the inner electrodes are generally silver-palladium alloy materials with high price, which also increases product cost; the outer electrodes and the inner electrodes are staggered in the thickness direction, which increases product thickness and volume to some extent and is not conducive to application. The utility model discloses a low-capacity through-hole ceramic dielectric capacitor based on high dielectric constant ceramic medium.
[0007] The utility model discloses a low-capacity through-hole ceramic dielectric capacitor based on high dielectric constant ceramic medium.
[0008] The utility model discloses a low-capacity through-hole ceramic dielectric capacitor based on high dielectric constant ceramic medium.
[0009] A low-capacity through-hole ceramic dielectric capacitor based on high dielectric constant ceramic medium, comprising a ceramic substrate, a through-hole is arranged on the ceramic substrate, a metal layer is arranged on the outer peripheral wall of the ceramic substrate and serves as a first end electrode, a metal layer is arranged on the hole wall of the through-hole and serves as a second end electrode, a plurality of layers of equidistantly arranged outer electrodes are arranged in the ceramic substrate, each layer of the outer electrode is connected with the first end electrode, characterized in that: the ceramic substrate is a high dielectric constant ceramic substrate, the distance m between the outer electrode and the through-hole is 0.1mm-1mm, and the distance d between the adjacent two layers of the outer electrode is 0.03mm-0.3mm.
[0010] As preferred, in order to make the capacitance of the sub-capacitor corresponding to each through-hole approximately between 200pF-800pF to better meet the application requirement of high-frequency filtering, the dielectric constant of the high dielectric constant ceramic substrate is 3000, the distance m between the outer electrode and the through-hole, the distance d between the adjacent two layers of the outer electrode, the diameter D of the through-hole and the number n of layers of the outer electrode satisfy the following conditions:
[0011]
[0012] As preferred, in order to meet the application requirement, the through-hole is multiple and uniformly distributed along the circumferential direction.
[0013] The utility model has the advantages that:
[0014] The utility model discloses a low-capacity through-hole ceramic dielectric capacitor based on high dielectric constant ceramic medium, which comprises a high dielectric constant ceramic substrate, a first end electrode, a second end electrode and an outer electrode, wherein the first end electrode and the second end electrode are arranged on the high dielectric constant ceramic substrate, and the outer electrode is arranged on the high dielectric constant ceramic substrate and is connected with the first end electrode and the second end electrode. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 It is a sectional view of the structure of a traditional low-capacity through-hole ceramic dielectric capacitor, and the section line is not shown in the figure;
[0016] Figure 2 It is a sectional view of the structure of a low-capacity through-hole ceramic dielectric capacitor based on high dielectric constant ceramic medium, and the section line is not shown in the figure. DETAILED DESCRIPTION
[0017] The utility model will be further described below in combination with the drawings:
[0018] As Figure 2As shown, the low-capacity through-hole ceramic capacitor based on a high dielectric constant ceramic dielectric of this invention includes a ceramic substrate, a through-hole 2 on the ceramic substrate, a metal layer on the outer peripheral wall of the ceramic substrate serving as a first terminal electrode 3, a metal layer on the wall of the through-hole 2 serving as a second terminal electrode 6, and multiple layers of equidistantly arranged external electrodes 4 inside the ceramic substrate, each external electrode 4 being connected to the first terminal electrode 3. The ceramic substrate is a high dielectric constant ceramic substrate 7, the distance m between the external electrode 4 and the through-hole 2 is 0.1mm to 1mm, and the distance d between two adjacent external electrode layers 4 is 0.03mm to 0.3mm.
[0019] Preferably, to ensure that the capacitance of the sub-capacitor corresponding to each through-hole 2 is approximately between 200pF and 800pF to better meet the application requirements of high-frequency filtering, the dielectric constant of the high-dielectric-constant ceramic substrate 7 is 3000. The following conditions are satisfied between the spacing m between the external electrode 4 and the through-hole 2, the spacing d between two adjacent layers of external electrodes 4, the diameter D of the through-hole 2, and the number of layers n of external electrodes 4:
[0020]
[0021] To meet application requirements, there are multiple through holes 2 (four in the figure) and they are evenly distributed along the circumference.
[0022] To better illustrate how the structural limitations involved in the above formula enable low capacities below 1000pF to better meet application requirements, the derivation process of the above formula will be explained in detail below.
[0023] like Figure 2 As shown, the parasitic capacitance C' of the sub-capacitor corresponding to each through-hole 2 of the low-capacitance through-hole ceramic capacitor based on a high dielectric constant ceramic dielectric of this utility model (because it is not the capacitance C formed between the conventional outer and inner electrodes, C' is used as a marking character) includes two parts.
[0024] One part is the parasitic capacitance C1' formed between the second terminal electrode 6 and the first terminal electrode 3, and the other part is the parasitic capacitance C2' formed between the second terminal electrode 6 and the external electrode 4, that is, C' = C1' + C2'. When there is no external electrode 4, C' = C1', that is, the parasitic capacitance C1' under this condition corresponds to the lowest capacitance value that the sub-capacitor can be designed for.
[0025] Based on actual production experience, the distribution range of C1' is approximately 150pF to 250pF. Therefore, when designing capacitors with a capacitance of 200pF to 800pF, the design range of C2' is approximately 0pF to 650pF.
[0026] The size of the parasitic capacitance C2' is proportional to the number of layers n of the outer electrode 4, the spacing d between adjacent outer electrodes 4, and the diameter D of the through hole 2, and is inversely proportional to the spacing m between the outer electrode 4 and the through hole 2. In general, the diameter D of the through hole 2 is of a specified size, so the size of the parasitic capacitance C2' is adjusted by adjusting the three parameters n, d and m, and the calculation formula of C2' is as follows:
[0027]
[0028] Since the design range of C2' is about 0pF~650pF, i.e.
[0029]
[0030] Further simplification is as follows:
[0031]
[0032] Therefore, That is, the limitation conditions for n, d and m, and also the structure limitation of the low-capacitance through-hole ceramic dielectric capacitor based on high dielectric constant ceramic medium according to the present application.
[0033] Note: The through hole 2, the first end electrode 3, the outer electrode 4, the second end electrode 6 and the related component names and mark numbers in the background art content are completely the same, because the focus of the present application is to improve the material of the ceramic substrate, and the specific size of the related structure is limited, and the components themselves are not improved, so the same component names and mark numbers are used.
[0034] The above embodiments are only preferred embodiments of the present application, and are not a limitation of the technical solutions of the present application. Any technical solution that can be realized on the basis of the above embodiments without creative labor shall be considered to fall within the scope of protection of the patent of the present application.
Claims
1. A low-capacitance through-hole ceramic dielectric capacitor based on high dielectric constant ceramic medium, comprising a ceramic substrate, a through-hole being provided on the ceramic substrate, a metal layer being provided on the outer peripheral wall of the ceramic substrate and serving as a first end electrode, a metal layer being provided on the hole wall of the through-hole and serving as a second end electrode, a plurality of layers of outer electrodes being provided in the ceramic substrate and arranged at equal intervals, each of the layers of outer electrodes being connected with the first end electrode, characterized in that: The ceramic substrate is a high dielectric constant ceramic substrate, the distance m between the outer electrode and the through-hole is 0.1mm-1mm, the distance d between the outer electrodes of two adjacent layers is 0.03mm-0.3mm. 2. The low capacitance high dielectric constant ceramic medium based through-hole ceramic dielectric capacitor according to claim 1, characterized in that: The dielectric constant of the high dielectric constant ceramic substrate is 3000, the distance m between the outer electrode and the through-hole, the distance d between the outer electrodes of two adjacent layers, the diameter D of the through-hole and the number n of the layers of the outer electrode satisfy the following conditions:
3. The low-capacitance high-dielectric-constant ceramic dielectric core- in-line ceramic capacitor according to claim 1 or 2, characterized in that: The through-holes are multiple and uniformly distributed in the circumferential direction.