JPH0729739A - Laminated coil - Google Patents

Abstract

PURPOSE:To obtain a laminated coil having a high Q factor. CONSTITUTION:A laminated coil comprises a block-material 11. The block material 11 comprises a plurality of insulator layers 12, 16, 20 and 24. Shielding electrodes 14 and 22 are respectively formed on the layers 12 and 20. A linear pattern electrode 18 is formed on the layer 16 and this electrode 18 is extracted to the opposed end parts of the layer 16. External electrodes are respectively formed on the side surfaces of the block material 11 in such a way as to connect to the extraction parts of the electrode 18. The thickness of the layer 16 between the electrodes 18 and 14 is formed in a thickness of 400mum or thicker. Similarly, the thickness of the layer 20 between the electrodes 18 and 22 is formed in a thickness of 400mum or thicker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated coil, and more particularly to a laminated coil having a pattern electrode formed inside and a shield electrode facing it.

[0002]

2. Description of the Related Art As a laminated coil, there is, for example, one in which a linear pattern electrode and a planar shield electrode facing the linear pattern electrode are formed. Such a laminated coil is
It is formed by printing an electrode paste in the shape of a pattern electrode and a shield electrode on a ceramic green sheet, stacking these ceramic green sheets and firing them. Then, the external electrodes are formed so as to be connected to both ends of the pattern electrode formed inside. Therefore, an inductance is formed between these external electrodes.

[0003]

However, in such a laminated coil, the magnetic field generated at the pattern electrode is affected by the shield electrode and the Q is lowered.

Therefore, a primary object of the present invention is to provide a laminated coil having a high Q.

[0005]

According to the present invention, two insulating layers to be laminated, a linear pattern electrode formed between the two insulating layers, and a pattern sandwiching the two insulating layers are provided. A laminated coil including two shield electrodes formed in a planar shape facing the electrodes, wherein the two insulator layers each have a thickness of 400 μm or more.

[0006]

By increasing the thickness of the insulator layer, the magnetic field generated at the pattern electrode is less likely to be affected by the shield electrode. In particular, it has been found that in a laminated coil having a linear pattern electrode, the Q of the laminated coil can be 100 or more by setting the thickness of the insulator layer to 400 μm or more.

[0007]

According to the present invention, a laminated coil having a Q of 100 or more can be obtained. Then, if this laminated coil is applied to a resonator or a filter, a resonator or a filter with a small insertion loss can be obtained.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

[0009]

1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG.
For example, the laminated coil 10 that can be used as a resonator includes a block body 11. As shown in FIG. 3, the block body 11 includes a first insulator layer 12. The first shield electrode 14 is formed on almost the entire surface of the first insulator layer 12. A second insulator layer 16 is formed on the first shield electrode 14. The pattern electrode 18 is formed on the second insulator layer 16. The pattern electrode 18 is formed in a linear shape, and both ends of the pattern electrode 18 are drawn out to opposite ends of the second insulator layer 16.

A third insulator layer 20 is formed on the pattern electrode 18. The second shield electrode 22 is formed on the third insulator layer 20. Second shield electrode 2
2 is formed on almost the entire surface of the third insulator layer 20. Further, a fourth insulator layer 24 is formed on the second shield electrode 22. These insulator layers 12, 16, 2
The block body 11 is formed by integrating 0 and 24.

Two external electrodes 26 and 28 are formed on the opposite side surfaces of the block body 11. These external electrodes 26 and 28 are electrically connected to the lead portions of the pattern electrode 18, respectively.

As a material for the insulating layers 12, 16, 20, and 24, a magnetic material or a dielectric material is used if necessary. The thickness of each of the second insulating layer 16 and the third insulating layer 20 is set to be 400 μm or more. The thickness of the second insulator layer 16 and the thickness of the third insulator layer 20 may be the same as or different from each other.

In order to manufacture this laminated coil 10, FIG.
As shown in, a plurality of insulating ceramic green sheets 30 are prepared. Then, the electrode paste 32 is printed on the insulating ceramic green sheets 30 in the shapes of the first shield electrode 14, the pattern electrode 18, and the second shield electrode 22. Further, the dummy insulating ceramic green sheets 30 are sandwiched between the insulating ceramic green sheets 30 each having the shape of each electrode coated with the electrode paste 32. The required number of dummy insulating ceramic green sheets 30 are sandwiched so that the thicknesses of the second insulating layer 16 and the third insulating layer 20 can be obtained. Further, the laminated coil 10 is manufactured by applying the electrode paste 32 in the shape of the external electrodes 26 and 28 and firing it so as to connect to the exposed portion of the electrode paste 32 for the pattern electrode. The insulating ceramic green sheets printed with the electrode paste for the internal electrodes may be laminated and fired to form the block body 11, and the side surface of the block body 11 may be baked with the electrode paste for the external electrode. Other known methods can be applied to the method of forming the external electrode.

In the laminated coil 10 thus obtained, an inductance is formed between the external electrodes 26 and 28. Regarding this laminated coil 10, the second insulating layer 16
And the thickness at the 3rd insulator layer 20 was changed, and Q in the frequency of 1 GHz was measured. And the result is shown in FIG.
It was shown to. As can be seen from FIG. 5, when the thickness of the insulating layers 16 and 20 is 300 μm or less, the Q value becomes less than 100. In contrast, the insulator layers 16 and 2
When the thickness of 0 is 400 μm or more, the value of Q can be 100 or more. As described above, when the thickness of the insulating layers 16 and 20 is 400 μm or more, a high Q can be obtained. Moreover, by making the insulator layers 16 and 20 the minimum thickness while ensuring the required Q value, the laminated coil 10 can be downsized without making it larger than necessary. Furthermore, when manufacturing the laminated coil 10, it is not necessary to use an insulating ceramic green sheet more than necessary, and an inexpensive laminated coil can be obtained.

FIG. 6 is an exploded perspective view showing an example in which the laminated coil of the present invention is applied to a bandpass filter. The bandpass filter 40 includes a first dielectric layer 42. The first shield electrode (ground electrode) 14 is formed on almost the entire surface of the first dielectric layer 42. The first shield electrode 14 is formed with three lead portions 14a, 14b, 14c. These drawer parts 14a, 14b, 14c
Are drawn to opposite ends of the first dielectric layer 42. The two lead portions 14a and 14b are led out to one end side of the first dielectric layer 42 with a space therebetween. And
The other lead-out portion 14c is led out to the other end side of the first dielectric layer 42.

A second dielectric layer 44 is formed on the first shield electrode 14. On the second dielectric layer 44,
Two linear pattern electrodes 18a and 18b are formed. The distance between the pattern electrodes 18a and 18b and the first shield electrode 14 is set to be 400 μm or more. These pattern electrodes 18a and 18b are
It is led out to the opposite end of the second dielectric layer 44. At this time, one ends of the pattern electrodes 18a and 18b are pulled out to positions corresponding to the lead portions 14a and 14b of the first shield electrode 14. A third dielectric layer 46 is formed on the pattern electrodes 18a and 18b. A first capacitor electrode 48 and a second capacitor electrode 50 are formed on the third dielectric layer 46. The capacitor electrodes 48 and 50 are formed on the third dielectric layer 46 at intervals and are connected to each other by the connection electrode 52.

A fourth dielectric layer 54 is formed on the two capacitor electrodes 48 and 50. A third capacitor electrode 56 and a fourth capacitor electrode 58 are formed on the fourth dielectric layer 54. The third capacitor electrode 56 is formed so as to face the first capacitor electrode 48. In addition, the fourth capacitor electrode 58
Is formed so as to face the second capacitor electrode 50. The third capacitor electrode 56 and the fourth capacitor electrode 58 are drawn out to both ends where the pattern electrodes 18a and 18b are not drawn out.

A fifth dielectric layer 60 is formed on the two capacitor electrodes 56 and 58. A fifth capacitor electrode 62 and a sixth capacitor electrode 64 are formed on the fifth dielectric layer 60. The fifth capacitor electrode 62 is formed so as to face the third capacitor electrode 56. In addition, the sixth capacitor electrode 64
Are formed so as to face the fourth capacitor electrode 58. The two capacitor electrodes 62 and 64 are drawn out to positions corresponding to the other ends of the pattern electrodes 18a and 18b.

A sixth dielectric layer 66 is formed on the two capacitor electrodes 62 and 64. The second shield electrode (ground electrode) 22 is formed on the sixth dielectric layer 66. The second shield electrode 22 is formed on almost the entire surface of the sixth dielectric layer 66. Then, the lead-out portions 22a, 22b, 22c are formed at positions corresponding to the lead-out portions 14a, 14b, 14c of the first shield electrode 14. The second shield electrode 22 and the pattern electrode 18
The distance between a and 18b is set to be 400 μm or more. Further, a seventh dielectric layer 68 is formed on the second shield electrode 22. The distance 400 between the second shield electrode 22 and the pattern electrodes 18a and 18b is 400.
Between μm, each capacitor electrode 48, 50, 56,
Since 58, 62, and 64 are interposed, when there is a concern that these may affect the magnetic field generated by the pattern electrodes 18a and 18b, the distance between these electrodes is 400.
It is desirable that the thickness be at least μm.

In this bandpass filter 40, the lead-out portion 14a of the first shield electrode 14 and the pattern electrode 18 are
One end of a and the lead-out portion 22a of the second shield electrode 22 are connected by an external electrode. Further, the lead-out portion 14b of the first shield electrode 14, one end of the pattern electrode 18b, and the lead-out portion 22b of the second shield electrode 22 are
Connected by external electrodes. Furthermore, the pattern electrode 1
The other end of 8a and the fifth capacitor electrode 62 are connected by an external electrode, and the other end of the pattern electrode 18b and a sixth capacitor electrode 64 are connected by an external electrode. Also, the third
An external electrode connected to each of the capacitor electrode 56 and the fourth capacitor electrode 58 is formed. Further, the lead-out portion 14c of the first shield electrode 14 and the second shield electrode 14
The lead-out portion 22c of the shield electrode 22 is connected by an external electrode.

The bandpass filter 40 is represented by an equivalent circuit shown in FIG. In this equivalent circuit, the two inductances L1 and L2 are respectively connected to the pattern electrode 1
8a, 18b. The capacitance C1 is the third
Capacitor electrode 56 and fifth capacitor electrode 62
And the electrostatic capacitance C2 is formed by the fourth capacitor electrode 58 and the sixth capacitor electrode 64. Further, the capacitance C3 connected in parallel with the inductance L1 is formed by the fifth capacitor electrode 62 and the second shield electrode 22, and the capacitance C4 connected in parallel with the inductance L2 is the sixth. It is formed by the capacitor electrode 64 and the second shield electrode 22. The capacitance C5 between the input and output terminals is formed by the first capacitor electrode 48, the third capacitor electrode 56, the second capacitor electrode 50, and the fourth capacitor electrode 58.

The frequency characteristic of the bandpass filter 40 was measured, and the result is shown in FIG. As can be seen from FIG. 8, in this bandpass filter 40, the insertion loss is 2
Good characteristics of dB or less could be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of the laminated coil shown in FIG.

FIG. 3 is an exploded perspective view of a block body of the laminated coil shown in FIG.

FIG. 4 is a perspective view showing one step of producing the laminated coil shown in FIG.

5 is a graph showing the relationship between the thickness of the insulating layer of the laminated coil shown in FIG. 1 and Q. FIG.

FIG. 6 is an exploded perspective view showing an example of a bandpass filter to which the laminated coil of the present invention is applied.

FIG. 7 is an equivalent circuit diagram of the bandpass filter shown in FIG.

8 is a graph showing frequency characteristics of the bandpass filter shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Laminated coil 11 Block body 12 1st insulator layer 14 1st shield electrode 16 2nd insulator layer 18 Pattern electrode 20 3rd insulator layer 22 2nd shield electrode 24 4th insulator layer 40 Bandpass filter

Claims (1)

[Claims] 1. Two laminated insulator layers, a linear pattern electrode formed between the two insulator layers, and a surface facing the pattern electrode with the two insulator layers sandwiched therebetween. A laminated coil including two shield electrodes formed in a striped shape, wherein the two insulator layers each have a thickness of 400 μm or more.