JP2003273688A - Laminated filter element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated filter element having an attenuation pole, whose structure is made sall and compact. <P>SOLUTION: At least a pair of stabs (335 and 345, for example) are provided in first helical lines 31, 33 and 35 connecting one terminal to a signal input electrode and connecting the other terminal to a signal output electrode and second helical lines 32, 34 and 36 connecting one terminal parallel thereto to a ground terminal and opening the other terminal. The pair of stabs are vertically overlapped with a dielectric between to form parallel planar capacitors. With the effects of the capacitors formed from the pair of stabs, the frequency of the attenuation pole is lowered with the same line length and attenuation characteristics are also improved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated filter element, and more particularly to a structure having an attenuation pole in attenuation characteristics and reducing the frequency of the attenuation pole by a capacitor included in a line.

[0002]

2. Description of the Related Art Recently, with the speeding up and downsizing of information equipment, there has been a great demand for downsizing and integration of parts used therein. Expectations are high for surface mount components aimed at small-scale integration, and in particular, expectations for monolithic ceramic electronic components are increasing. Multilayer ceramic components include multilayer filter elements and multilayer chip coils.

A distributed constant type noise filter is one of the laminated filter elements. It is a trap type filter that uses a distributed constant type coupled line and has an attenuation pole in the high frequency region. The equivalent circuit is shown in FIG. A line 72 having one end connected to a ground terminal (GND) and the other end opened is electromagnetically coupled with a dielectric substance sandwiched therebetween. In this case, the electric length of the line 72 connected to the ground terminal (GND) is 1 /
A trap characteristic having an attenuation pole is obtained at frequencies of four wavelengths.

If this trap characteristic is used to apply to a noise filter or a waveform shaping filter, the element becomes large. For example, the frequency of the attenuation pole = 1GH
Assuming z, the quarter wavelength is 7.5 cm in the atmosphere.
When a filter element is made using an alumina substrate (relative permittivity εr≈9), the dimensions are 1 / (εr) ^1/2 ≈1 /
It is as small as 3, but requires a length of about 2.5 cm.

Therefore, conventionally, as shown in FIG. 8, the bonding line is formed in a spiral shape on the alumina substrate. The signal line 71 in FIG. 7 corresponds to the one formed by connecting the spiral coupling line 82 in FIG. 8B and the linear coupling line 83 in FIG. 8C at the via hole P and the connection portion Q. One end is connected to the signal input electrode 1 and the other end is connected to the signal output electrode 2.
The signal line 72 in FIG. 7 corresponds to the spiral coupling line 81 in FIG. Ground terminal (GN
The line 81 having one end connected to D) and the other end open is arranged at a position where they are electromagnetically coupled to each other through the alumina substrate. In this case, although the trap characteristic is obtained, the relative permittivity is determined and the size is determined depending on the substrate used. On the other hand, since there is a limit to the line length that can be obtained on the same plane, the element becomes large, which is not suitable for downsizing the element or for high-density mounting equipment.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a laminated filter element having an attenuation pole and having a more compact and compact structure. And

[0007]

In order to solve the above problems, the laminated filter element of the present invention has a first spiral having one end connected to a signal input electrode and the other end connected to a signal output electrode. A second spiral-shaped line having one end connected to the ground electrode and the other end open, and arranged in parallel with the first spiral-shaped line. In the laminated filter element in which the frequency of the attenuation pole is determined by the line length of the spiral line, the first spiral line and the second spiral line have at least a pair of stubs, and the pair of stubs Are arranged at overlapping positions to form a parallel plate type capacitor.

The spiral line is formed by connecting a plurality of U-shaped conductor patterns through via holes, and the stub is provided at each corner of three sides of the U-shaped conductor pattern. It is preferably formed so as to project from.

It is preferable that the via hole connection portion is arranged on a stub protruding from the U-shaped conductor pattern.

The laminated filter element of the present invention has at least a pair of stubs on a spiral line connected to the signal input electrode and the signal output electrode and a second spiral line connected to a grounding terminal parallel to the spiral line. To provide. The pair of stubs are vertically overlapped with each other with the dielectric material sandwiched therebetween to form a parallel plate type capacitor. Due to the effect of forming the capacitor by the pair of stubs, the frequency of the attenuation pole can be reduced with the same size, that is, with the same line length, and the attenuation characteristic is improved. The number of layers of the element can be reduced. This makes it possible to reduce the size of the laminated filter element and reduce the manufacturing cost.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a laminated filter element according to the present invention will be described below with reference to FIGS.

FIG. 1 is a view showing the outer appearance of the laminated filter element of the present invention. This laminated LC filter element has a signal input electrode 1, a signal output electrode 2, and grounding electrodes 3 and 4 on a laminated ceramic body 10 formed by laminating and sintering a plurality of layers of ceramic green sheets. , Has a structure as a surface mounting chip component.

2 (a) and 2 (b) are sectional views showing the laminated structure of the laminated filter element of the present invention, in which (a) shows the lateral direction and (b) shows the longitudinal direction. The laminated filter element is configured by forming a conductor layer 22 on a sheet-shaped ceramic layer 21 and stacking a plurality of these layers. A plain ceramic layer having no conductor layer is laminated on the upper side and the lower side. Between each conductor layer, a via hole provided in the ceramic layer is filled with a conductor and connected to each other to form a spiral coil conductor (line) as described later. Conductor layer 22
A part of each of the electrodes extends to the edge of the ceramic layer 21 and is connected to the electrodes 1, 2, 3, and 4 shown in FIG. 1, respectively.

FIG. 3 is a diagram showing an example of the structure of conductor patterns arranged in the dielectric layer (ceramic layer) of the laminated filter element of the present invention, and embodies the laminated filter element of the equivalent circuit shown in FIG. . In FIG. 3, the layers (a) to (g) are stacked in this order from top to bottom. The connection state will be described below.

The end portion of the conductor pattern 35 shown in FIG. 3 (e) reaches the edge of the chip and is connected to the external signal input electrode 1. The conductor pattern 35 is a part of the spiral line 51 shown in FIG. The conductor pattern 31 shown in FIG. 3A has its end reaching the edge of the chip and connected to the external signal output electrode 2. The conductor pattern 31 is also
It is a part of the spiral line 51. The conductor pattern 35 of FIG. 3E and the conductor pattern 33 of FIG.
The conductor pattern 31 of (a) constitutes one spiral line 51.

That is, the conductor pattern 35 and the conductor pattern 3
3 are connected to each other by stacking them through the connection portion J of (e) and the via hole H of the conductor (d) which is filled with the conductor and the via hole D 2 of the conductor (c) which is filled with the conductor. The conductor pattern 33 and the conductor pattern 31 are connected by stacking the via hole A in which the conductor of (a) is filled and the connection portion E of (c) via the via hole c in which the conductor of (b) is filled. It The via hole to be connected and the connecting portion are arranged at positions vertically overlapping with each other. Stacking the dielectric layers,
These via holes have a structure in which they are mechanically contacted with each other and the holes are filled with a conductor so that they are electrically connected. Therefore,
Conductor pattern 35, conductor pattern 33, and conductor pattern 3
Reference numeral 1 constitutes one spiral line, that is, a line between the signal input electrode 1 and the signal output electrode 2.

With the conductor pattern 32 of FIG. 2B, the conductor pattern 34 of FIG. 2D and the conductor pattern 36 of FIG. 2F, one spiral line 52 (see FIG. 5) connected to the ground electrode is formed. is doing. The conductor pattern 32 and the conductor pattern 34 are connected to each other through the via hole B filled with conductors and the via hole F filled with conductors in (c) at the connection portion of (c).
Connected by stacking on I. The conductor pattern 34 and the conductor pattern 36 are connected by being laminated on the connection portion M of (f) via the via hole G of (d) and the via hole K of (e). This line is further connected to the conductor pattern 37 of (g) via the via hole L of (f) and the connection portion N of (g). The end of the conductor pattern 37 reaches the edge of the chip and is connected to an external grounding terminal. The spiral line 51 and the spiral line 52 are arranged at positions where they are electromagnetically and electrostatically coupled to each other.

The stub of the present invention is formed so that the three sides of the U-shaped conductor pattern project from the respective corners. In FIG. 3A, 311, 312, 31
3 and 314, and 321, 32 in FIG.
2, 323, 324, and 33 in FIG.
1, 332, 333, 334, and 341, 342, 343, 344 in FIG. 3D, and FIG.
351, 352, 353, 354 in FIG.
In (f), 361, 362, 363, and 364. 311 and 321 are arranged in a pair so as to face each other. Similarly, 312 and 322, 313 and 32
3, 314 and 324 ... are paired.

FIG. 4 is a diagram for explaining the stub of the laminated filter element of the present invention in detail. FIG. 4 is an enlarged view of a state in which the conductor pattern 33 of FIG. 3C and the conductor pattern 34 of FIG.
Although the conductor pattern 33 and the conductor pattern 34 are almost overlapped with each other, the stub 345 and the stub 335 are not overlapped with each other. Also, the stub 346 and the stub 336 do not overlap. This part is responsible for electrical connection with other conductor patterns through via holes E and F. On the other hand, the stub 331 of the conductor pattern 33 and the stub 341 of the conductor pattern 34 in the overlapping portion form a parallel plate type capacitor. Similarly, the stub 332 of the conductor pattern 33 and the stub 342 of the conductor pattern 34 overlap with each other to form a parallel plate capacitor, and the stub 333 of the conductor pattern 33 and the stub 343 of the conductor pattern 34 overlap with each other and the stub 33 of the conductor pattern 33 overlaps. The stubs 344 of the conductor pattern 34 overlap with each other to form parallel plate capacitors.

FIG. 5 shows an equivalent circuit of the laminated filter element of the present invention. A line 51 is arranged between the signal input electrode 1 and the signal input electrode 2, and a line 52 having one end grounded and the other end open is arranged in parallel to the line 51 and electromagnetically coupled. Further, a capacitive coupling as a parallel plate type capacitor is added between the line 51 and the line 52 by a pair of stubs. That is, there will be additional capacitors 54, 55, 56 formed by the stubs between line 51 and line 52.

FIG. 6 is a diagram showing the attenuation characteristics of the present invention and the conventional laminated filter element in comparison. As shown in FIG. 6, regarding the attenuation pole, the attenuation amount is 35 dB at the frequency of 1.6 GHz in the conventional example, whereas the attenuation pole of the multilayer filter element of the present invention is the attenuation amount at the frequency of 1.2 GHz. Data of 55 dB is obtained. The attenuation characteristics of the laminated filter element of the present invention are also: attenuation = 12 dB at frequency = 0.5 GHz, attenuation = 30 dB at frequency = 1.0 GHz, attenuation = 35 dB at frequency = 1.5 GHz, frequency = 2. The data is the amount of attenuation = 20 dB at 0 GHz. It can be seen that the attenuation characteristic is significantly improved as compared with the conventional example, and the shift is made to the low frequency side.

Although one embodiment of the present invention has been described so far, it goes without saying that the present invention is not limited to the above-described embodiment and may be implemented in various different forms within the scope of the technical idea thereof.

[0023]

As described above, according to the multilayer filter element of the present invention, the first spiral line connected to the signal input electrode and the signal output electrode and one end parallel to the first spiral line are connected to the grounding terminal. By providing at least a pair of stubs on the second spiral line whose other end is opened, the pair of stubs are vertically overlapped with the dielectric material sandwiched therebetween to form a parallel plate type capacitor. Due to the effect of forming a capacitor by the pair of stubs, the frequency of the attenuation pole can be lowered and the attenuation characteristic can be improved with the same line length. If the attenuation amount is fixed, the number of laminated filter elements can be reduced,
The laminated filter element can be downsized, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is an external view of a laminated filter element of the present invention.

FIG. 2 is a cross-sectional view of a laminated filter element of the present invention,
(A) shows a lateral direction and (b) shows a longitudinal direction.

3 (a) to 3 (g) are diagrams showing an arrangement example of conductor patterns arranged in a dielectric layer of the multilayer filter element of the present invention.

FIG. 4 is a diagram for explaining a stub of the laminated filter element of the present invention.

FIG. 5 is a diagram showing an equivalent circuit of the multilayer filter element of the present invention.

FIG. 6 is a diagram showing the attenuation characteristics of the multilayer filter element of the present invention and a conventional example in comparison.

FIG. 7 is a diagram showing an equivalent circuit of a conventional multilayer filter element.

FIG. 8 is a diagram showing an example of conductor pattern arrangement of a conventional multilayer filter element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 signal input electrode 2 grounding electrode 3 signal output electrode 4 dielectric layer 5 conductor pattern 6 conductor pattern 21 dielectric layer (ceramic layer) 22 conductor layers 31-36 spiral conductor pattern 37 ground electrode connection Conductor patterns 39, 40 Spiral conductor patterns 311 to 314 Stubs 321 to 324 that are a part of the conductor pattern 31 Stubs 331 to 344 that are a part of the conductor pattern 32 Stubs 341 to 344 that are a part of the conductor pattern 33 Stubs 351 to 354 that are a part of the conductor pattern 34 Stubs 361 to 364 that are a part of the conductor pattern 35 Stubs 335 and 336 that are a part of the conductor pattern 36 Stubs 345 and 346 that are a part of the conductor pattern 33 Stubs 51 and 52 which are a part of 34 Lines 54, 55 and 56 Capacitors 71 and 72 Lines 81 to 82 Spiral conductor pattern 83 Linear conductor patterns A, B, C, D, F, G Via holes H, K, L, P Via holes E, I, J, M, N, Q Connections

Claims (3)

[Claims] 1. A first spiral line having one end connected to a signal input electrode and the other end connected to a signal output electrode,
A second spiral line having one end connected to the grounding electrode and the other end open, and arranged in parallel with the first spiral line; In a laminated filter element in which a frequency of an attenuation pole is determined by a length, the first spiral line and the second spiral line have at least a pair of stubs, and the pair of stubs are arranged at overlapping positions. A laminated filter element characterized by forming a parallel plate capacitor. 2. The spiral line is formed by connecting a plurality of U-shaped conductor patterns through via holes, and the stub is provided on each of three sides of the U-shaped conductor pattern. The multilayer filter element according to claim 1, wherein the multilayer filter element is formed so as to project from a corner portion. 3. The multilayer filter element according to claim 2, wherein the connection portion formed by the via hole is arranged on a stub protruding from the U-shaped conductor pattern.