JPH06224602A - Laminated band pass filter - Google Patents

Abstract

PURPOSE:To obtain the frequency characteristic as designed by providing a ground conductor between line conductors forming each resonator and laminating a coupling capacitor with each resonator via ground conductors. CONSTITUTION:The laminated band pass filter 1 is formed by laminating ground conductors 3a-3d, line conductors 4a-4c being components of resonators in the inside of a ceramic-made dielectric body 2 and capacitor electrodes 5a-5c forming capacitors used to couple the resonators via each dielectric layer, pressing them, sintering them, cutting side faces of the laminators whose conductor connection ends are exposed at a prescribed width and forming outer electrodes a-f connecting to the connection ends of each conductor with baking or the like. Thus, the line conductors 4a-4c being components of each stage resonator are formed to be different layers and the ground conductors 3a-3d are provided between the layers respectively via the ground conductor 3d acting like one electrode of the capacitors on the front or rear sides of the capacitor laminator coupling the resonators of each stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency laminated band pass filter.

[0002]

2. Description of the Related Art A laminated bandpass filter is one in which a line conductor, a ground conductor, and a dielectric are alternately laminated by a printing method or a sheet method to form an LC resonator inside the laminated body. . In such a multilayer bandpass filter, a plurality of resonators are built in one laminated body, and these resonators are capacitively coupled through a coupling capacitor to make the rise of the resonance frequency steep and improve the characteristics. It is possible to improve.

[0003]

However, in the conventional multi-stage laminated bandpass filter, since the capacitors for coupling the respective resonators are formed by the line conductors facing each other, the respective line conductors constituting the resonators are formed. There is a problem in that they interfere with each other and it is difficult to obtain the frequency characteristics as designed.

In view of the above situation, it is an object of the present invention to provide a laminated bandpass filter which can easily obtain a frequency characteristic as designed.

[0005]

In order to achieve the above object, the present invention provides a multilayer bandpass filter constituted by a plurality of resonators each comprising a laminated body of a line conductor and a dielectric material, and a resonance of each stage. The line conductors that respectively form the resonators in different layers, and by forming a grounding conductor between them, a capacitor coupling between the resonators of each stage is formed on at least one of the front surface and the back surface of the laminated body, The capacitor is characterized in that the capacitors are laminated via a ground conductor that also serves as one electrode of the capacitor.

[0006]

According to the multilayer bandpass filter of the present invention, the line conductors of each stage are laminated via the ground conductor, and the resonator coupling capacitor is laminated on the laminated body via the ground conductor. The interference between the line conductors and the coupling capacitor is reduced.

[0007]

1 is a diagram showing a manufacturing process of an embodiment of a laminated bandpass filter according to the present invention, FIG. 2 (A) is a perspective view of the embodiment, FIG. 2 (B) is an equivalent circuit diagram thereof, and FIG. [FIG. 3] is a perspective view showing a conductor inside a laminated body. As shown in FIG. 3, the multilayer bandpass filter 1 includes a grounded conductors 3a to 3d and line conductors 4a to 4c, which form a resonator, inside a dielectric 2 made of ceramic, and a capacitor that connects the resonators. Capacitor electrodes 5a to 5c are laminated via a dielectric layer, pressure-bonded, fired, and the side surface of the laminated body in which the connection end of each conductor is exposed is chamfered with a width dimension W (hatched portion). Shows the cutting allowance of the conductor), and as shown in FIG. 2 (A), the external electrodes a to f indicated by the two-dot chain line are formed on the outer surface by baking or the like by connecting to the connection ends of the respective conductors. Is. In this example, a plurality of stages of resonators are formed in the back layer (X part), and a capacitor for capacitively coupling each resonator is formed in the surface layer (Y part). The capacitor part may be provided on the back layer or may be provided separately on the front and back sides.

FIG. 1 shows one manufacturing process of the laminated bandpass filter 1. The manufacturing process will be described with reference to this drawing. First, a ceramic dielectric material is used.
A base layer is formed by a predetermined number of dielectric sheets 2a in a sheet shape (A), and connection ends b, d, f (these connection ends are shown in FIG. 2A). The ground conductor 3a, which is connected to the external electrodes b, d, and f having the same reference numerals, and the connection terminals a, c, and e which will be described later) is formed of a conductor paste, for example, by a printing method. Etc. (B), and a predetermined number of dielectric sheets 2b are laminated thereon (C).

Next, a conductor sheet is placed on the dielectric sheet 2b.
U-shaped line conductor 4a for forming the first-stage resonator
With their connecting ends a and b facing the same side as the connecting ends b, d and f of the ground conductor 3a, and the connecting end a for grounding is connected to the connecting end b of the ground conductor 3a. It is formed on the left side of the drawing so as to be at the same position (D), and a predetermined number of dielectric sheets 2c are laminated thereon (E).

Next, the ground conductor 3b having the connection ends b, d, f is provided on the dielectric sheet 2c.
It is formed so that f is at the same position as each of the connection ends b, d, f of the ground conductor 3a (F), and a predetermined number of dielectric sheets 2d are laminated thereon (G).

Next, on the dielectric sheet 2d, a U-shaped line conductor 4b for the second-stage resonator is formed, and its connecting ends c and d are the same as the connecting ends a and b of the line conductor 4a. To the side,
Further, it is formed in the center in the drawing (H) so as not to face the line conductor 4a, and so that the ground connection end portion d is located at the same position as the ground connection end portions d of the ground conductors 3a and 3b (H).
A predetermined number of dielectric sheets 2e are laminated thereon (I).

Next, a grounding conductor 3c having connecting ends b, d, f is formed on the dielectric sheet 2e, and each connecting end b,
d and f are the connection ends b of the ground conductors 3a and 3b,
formed so that they are at the same positions as d and f respectively (J),
A predetermined number of dielectric sheets 2f are laminated thereon (K).

Next, a U-shaped line conductor 4c for constructing a third stage resonator is provided on the dielectric sheet 2f, and its connecting end portion e,
f is the connecting end portions a, b, c, d of the line conductors 4a, 4b
In the drawing, the grounding connection terminal f should be in the same position as the grounding connection terminal f of the grounding conductors 3a to 3c and should not face the line conductors 4a and 4b. It is formed on the right side (L), and a predetermined number of dielectric sheets 2g are laminated thereon (M).

Next, a ground conductor 3d having connection ends b, d, f is provided on the dielectric sheet 2g.
It is formed in the same manner as 3c (N), and a predetermined number of dielectric sheets 2h are laminated thereon (O).

Next, on the dielectric sheet 2h, a capacitor electrode having a connection end portion a connected to the connection end portion a of the first-stage resonator constituting line conductor 4a via an external electrode. 5a and a capacitor electrode 5b having a connection end e connected to the connection end e of the line conductor 4c for forming a third stage resonator via an external electrode, and these connection ends a and e are described above. The ground conductor 3d is formed toward the same side as the connection ends b, d, f (P), and a predetermined number of dielectric sheets 2i are laminated thereon (Q).

Next, a capacitor electrode having a connecting end portion c connected to the connecting end portion c of the second stage resonator constituting line conductor 4b via an external electrode on the dielectric sheet 2i. 5c is formed at a position facing the capacitor electrodes 5a, 5b, and the connecting end portion c is formed on the same side as the connecting end portions a, e (R), and a predetermined upper surface coating is formed thereon. A number of dielectric sheets 2j are stacked (S).

The dielectric sheets 2a to 2j are not limited to so-called dielectric materials, but may be insulating materials having a dielectric constant.

A large number of sheets thus obtained are cut and fired, and the side faces of the laminate are surface-cut as described above, and then the external electrodes a to f are formed. Two
The laminated bandpass filter 1 shown in FIG.

In the multilayer bandpass filter 1 thus manufactured, the connection ends a to f indicated by the same reference numerals of the conductors are connected by the external electrodes a to f to connect the line conductor 4a and the dielectric sheet. 2B between the ground conductors 3a and 3b facing each other with the dielectric layer formed by the gates 2b and 2c interposed therebetween.
The capacitor C1 shown in the equivalent circuit diagram is formed, and the first resonator 7 is formed by the capacitor C1 and the line conductor 4a. In addition, the line conductor 4b and the dielectric sheets 2d, 2
The ground conductor 3 facing each other with the dielectric layer formed by e interposed therebetween.
b and 3c, a capacitor C2 is formed, the capacitor C2 and the line conductor 4b form a second resonator 8, and a dielectric formed by the line conductor 4c and the dielectric sheets 2f and 2g. A capacitor C3 is formed between the grounding conductors 3c and 3d facing each other with the body layer interposed therebetween.
And the line conductor 4c form a third resonator 9. A capacitor C4 is formed between the capacitor electrode 5a and the capacitor electrode 5c facing each other with the dielectric sheet 2i interposed therebetween, and the capacitor electrode 5b and the capacitor electrode 5c facing each other with the dielectric sheet 2i sandwiched therebetween. In between, a capacitor C5 is formed.

With the capacitors C4 and C5, the first
Through the third resonator 7, 8, 9 are capacitively coupled.

As described above, the capacitors C4 and C5 for coupling the resonators are formed separately from the layer in which the resonators are formed, so that the interference of the capacitors C4 and C5 with the resonators is reduced. And the line conductor 4a
And the line conductor 4b are shielded by the ground conductor 3b, and the line conductor 4b and the line conductor 4c are grounded by the ground conductor 3c.
Since it is shielded by, the interference between the line conductors is eliminated and the frequency characteristic as designed can be obtained. Moreover, since a plurality of resonators are coupled, a resonance frequency characteristic having a steep rise can be obtained. Furthermore, since the connecting ends a to f of the U-shaped line conductors 4a to 4c are cut by mechanically cutting one side surface of the laminated body, by adjusting the width dimension W of the cutting, It is possible to easily and accurately adjust the frequency, and to improve the productivity of the laminated bandpass filter, without requiring much positioning accuracy as compared with trimming by the like.

FIG. 4 is a diagram showing a manufacturing process of another embodiment of the laminated bandpass filter according to the present invention, and FIG. 5 is a perspective view of the embodiment. During the manufacturing process of this example, the steps of forming the resonator are similar to those of the above-described embodiment shown in FIGS. 2A to 2N, and therefore only the subsequent steps will be described in this example.

As shown in FIG. 4, a predetermined number of dielectric sheets 2k are laminated on the laminated body having the resonators (A), and then the dielectric sheets 2k are laminated. A capacitor electrode 5d having a connection end portion a is formed (B), and a predetermined number of dielectric sheets 2m are laminated thereon (C).

Next, the capacitor electrode 5e having the connecting end portion c is formed on the dielectric sheet 2m.
d, and the connecting end portion c is connected to the connecting end portion a.
It is formed toward the same side as (D), and a predetermined number of dielectric sheets 2n are laminated thereon (E).

Next, a capacitor electrode 5f having a connecting end e is formed on the dielectric sheet 2n.
e, and the connecting end e is connected to the connecting end c.
(F), and a predetermined number of dielectric sheets 2p for covering the upper surface are laminated thereon (F).

The laminate thus obtained was pressure-bonded and fired, as shown in FIG.
The laminated band pass filter 1A is manufactured by forming the external electrodes a to f on the outer surface by baking or the like.

In the laminated bandpass filter 1A manufactured in this way, the capacitor electrode 5d and the dielectric sheet are arranged.
Between the capacitor electrodes 5e facing each other with the gate 2n in between,
The capacitor C4 shown in FIG. 2B is formed, and the capacitor C5 is formed between the capacitor electrode 5e and the capacitor electrode 5f facing each other with the dielectric sheet 2p interposed therebetween.

Thus, the laminated band pass filter 1A
In the above, since the same effect as that of the above-described embodiment is obtained and the capacitors C4 and C5 are formed in different layers,
The interference of the capacitors C4 and C5 with the resonator can be further reduced, and the frequency characteristics as designed can be easily obtained.

[0029]

According to the first aspect of the present invention, the ground conductor is provided between the line conductors forming each resonator, and the coupling capacitor is laminated with the resonator via the ground conductor. Interference with the capacitor disappears,
The frequency characteristics as designed can be obtained.

According to the second aspect, since the resonators of three stages or more are coupled, the resonance frequency characteristic having a steeper rise can be obtained.

According to the third aspect of the present invention, the line length of the line conductor forming the resonator can be adjusted by surface-cutting one side surface of the laminated body.
In addition, the resonance frequency can be adjusted accurately, and the productivity can be improved. Further, the appearance is not damaged by the frequency adjustment.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of an embodiment of a laminated bandpass filter according to the present invention.

2A is a perspective view of the embodiment, and FIG. 2B is an equivalent circuit diagram thereof.

FIG. 3 is a perspective view showing a conductor inside a laminate of the example.

FIG. 4 is a diagram showing a manufacturing process of another embodiment of the multilayer bandpass filter according to the present invention.

FIG. 5 is a perspective view showing another embodiment of the multilayer bandpass filter according to the present invention.

[Explanation of symbols]

 1, 1A Multilayer bandpass filter 2 Dielectrics 2a to 2p Dielectric sheets 3a to 3d Ground conductors 4a to 4c Line conductors 5a to 5f Capacitor electrodes 7 First resonator 8 Second resonator 9 Third resonance Container C1 to C7 Capacitors a to f Connection ends (external electrodes)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H03H 7/075 A 8321-5J

Claims (3)

[Claims] 1. A multilayer bandpass filter comprising a plurality of resonator stages each comprising a laminated body of a line conductor and a dielectric, wherein line conductors constituting the respective resonators are provided in different layers, and A grounding conductor is provided between them to form a capacitor for coupling between the resonators of each stage, and the capacitor is laminated on at least one of the front surface and the back surface of the laminated body through the grounding conductor which also serves as one electrode of the capacitor. A laminated bandpass filter characterized by the above. 2. The multilayer bandpass filter according to claim 1, wherein the resonator is formed in three or more stages. 3. The line conductor forming each of the resonators is formed in a U shape, the connecting end portions of which are exposed on the same side surface of the laminate, and the external electrode is provided at the connecting end portion. A laminated band-pass filter characterized by being formed.