Laminated sheet type filter and preparation method thereof

Abstract

The invention discloses a laminated sheet type filter and a preparation method thereof, belonging to the technical field of electron component. The filter is formed by compounding a laminated sheet type capacitance and a laminated sheet type magnetic core inductance, wherein the laminated sheet type capacitance is laminated and sintered by multiple layers of ferrite diaphragms of which the surface is printed with conductor wires, composite medium material is arranged between the terminal electrode contained by the laminated sheet type capacitance and a ground electrode, and the composite medium material comprises ferrite material and columnar ceramic arrays distributed in the ferrite material. The preparation method comprises the following steps: burdening, casting, pulping, forming arrays / interconnecting holes, filling ceramics / conductor paste, printing conduction band, laminating, equalizing pressure of hot water, cutting, burning, blocking and the like. The invention increases the equivalent dielectric constant in common ferrite structure by adding the columnar ceramic array structure in the capacitance part of the laminated sheet type filter, improves Q value and capacity and effectively lowers the off frequency of the filter and improves the out of band rejection characteristic of the filter.

Description

technical field [0001] The invention belongs to the technical field of electronic components, and relates to a chip filter, in particular to a laminated chip ferrite filter containing a dielectric ceramic columnar array and a preparation method thereof. Background technique [0002] As the whole machine and system have higher and higher requirements on the size and weight of electronic components, the filter is a passive component widely used in the system and the whole machine, so it is very important to reduce its size and weight, especially for anti-electromagnetic interference applications The research of the anti-electromagnetic interference filter with small size and high reliability has become a current focus of attention. For this reason, manufacturers at home and abroad develop and produce miniaturized, low cut-off frequency anti-electromagnetic interference filters in the form of multi-layer chip structures. [0003] At present, the anti-electromagnetic interferen...

AI Technical Summary

Problems solved by technology

A common structure is an LC filter made of a single dielectric ceramic material. The filter with this structure improves the out-of-band rejection characteristics, but to meet the application requirements of a lower cut-off frequency, it is necessary to increase the capacitance of the filter and Inductance value, because the magnetic permeability of dielectric ceramics is very small, the inductance value can only be increased by increasing the number of inductance layers, thus greatly increasing the volume and weight of the filter

There are also LC-type filters made of a single ferrite material. Also because the dielectric constant of the ferrite material is very small, if you want to increase the capacitance to meet the requirements of a lower cut-off frequency, you can only increase the number of capacitor layers. Realization will also greatly increase the volume and weight of the filter; at the same time, the operating frequency range of the filter is usually lower than 500MHz due to the low resonance frequency of a single ferrite material

Another type of filter is formed by stacking the inductance part with ferrite materials, and the capacitor part is formed by stacking dielectric ceramic materials, and then combining the two parts into one to form a split-layer LC filter. Although this type of filter improves The out-of-band characteristics of the filter are improved, but due to the interface effect between the ceramic layer and the ferrite layer, and the crystal grain size and shrinkage rate of the two materials are different, a large amount of stress will be generated at the interface during debinding and sintering. The two materials The difference in shrinkage rate and direction accelerates the accumulation of stress. This interface stress plus the shrinkage mismatch between material layers often causes cracks, delamination and warping inside the filter, and in severe cases, it will cause cracking of the ceramic body. Greatly reduces the reliability of the filter

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