JPH05335866A - High frequency filter - Google Patents

Abstract

PURPOSE:To easily manufacture the subject filter by setting a GND electrode so as to prevent production of a deviation in input output impedance or deviation in the resonance frequency. CONSTITUTION:A GND electrode pattern 17 is provided on a layer 10-5 at the outside of a multi-layer circuit board and capacitor electrode patterns 11-14 and coil patterns 15, 16 are provided on a 2nd layer 10-2, a 3rd layer 10-3, a 4th layer 10-4 being inner layers. Then the capacitor electrode pattern 13/the GND electrode pattern 17 and the capacitor electrode pattern 14/the GND electrode pattern 17 form respectively capacitors C1, C2 having a GND potential and the GND electrode pattern 17 is used for shielding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency filter, and more particularly to a high frequency filter used for various communication equipments, electronic equipments and the like.

[0002]

2. Description of the Related Art FIG. 5 is an explanatory view of a conventional example, FIG. 5A is a circuit diagram of a high frequency filter, FIG. 5B is a cross sectional view of the high frequency filter (No. 1), and FIG. 5C is a cross sectional view of the high frequency filter (No. 2). Is.

In the figure, C ₁ , C ₂ and C ₃ are capacitors and L
Is a coil, IN is an input terminal, OUT is an output terminal, 1 is a multilayer substrate, 2 is a blind through hole, 3, 5, and 6 are capacitor electrode patterns, 4 is a coil pattern, and 7 and 8 are GND electrode patterns.

As a circuit of a conventional high frequency filter, there is, for example, the circuit (low-pass filter) shown in FIG. 5A. This circuit has one coil L and three capacitors C ₁ ,
It is composed of C ₂ and C ₃ .

The coil L and the capacitors C _{1 to} C ₃ described above.
Is mounted on a multilayer board, the cross-sectional structure is
For example, it becomes like FIG. 5B. Generally, a coil, a capacitor, and the like that form a high frequency filter are easily affected by an electric power from the outside.

Therefore, for the coil and the capacitor, GN
A D electrode pattern is added to form a shielded structure.
That is, the GND electrode pattern (solid GND pattern) 7 is provided on the first layer 1-1 of the multilayer substrate 1.

Further, the capacitor electrode patterns 3, 5, 6 and the coil pattern 4 are provided on the second layer 1-2, the third layer 1-3 and the fourth layer 1-4 of the multilayer substrate 1, respectively. Further, a GND electrode pattern (solid GND pattern) 8 is provided on the back side (outer side) of the fourth layer 1-4.

Then, predetermined portions are connected by blind through holes (through holes whose inside is filled with a conductor) 2 and are connected as shown in the circuit diagram of FIG. 5A. in this case,
The coil pattern 4 on the second layer to the fourth layer 1-2 to 1-4 constitutes a coil L of 3 turns, and the second layer to the fourth layer 1
A capacitor C ₁ is formed by the capacitor electrode patterns 3 on −2 to 1-4.

A capacitor C ₃ is formed by the capacitor electrode patterns 5 on the second to fourth layers 1-2 to 1-4, and the capacitors C ₃ are formed on the second to fourth layers 1-2 to 1-4. The capacitor electrode pattern 6 constitutes a capacitor C ₂ .

The coil L and the capacitor C
Both sides of _{1 to} C ₃ (both sides in the stacking direction) are sandwiched by the GND electrode patterns 7 and 8 to shield both sides.

However, as described above, even if the circuit of FIG. 5A is formed into a multi-layer substrate and the GND electrode patterns are added to the front and back surfaces thereof, it is difficult to perform the intended operation. This is because the GND electrode patterns 7 and 8 described above cause unnecessary stray capacitance, which causes a shift in input / output impedance and a shift in resonance frequency.

Therefore, it is necessary to set the GND electrode pattern while adjusting the deviation of the input / output impedance and the deviation of the resonance frequency. However, this work is extremely difficult and difficult to achieve.

Therefore, it is conceivable to adopt the configuration shown in FIG. 5C. FIG. 5C is an example in which the insulating layer of the high frequency filter shown in FIG. 5B is thickened, and the coil L and the capacitor C are shown.
Each pattern structure of _{1 to} C ₃ is the same.

That is, in FIG. 5B, several insulating layers (dielectric layers) are provided below the GND electrode pattern on the first layer 1-1 and below the fourth layer 1-4. Several insulating layers (dielectric layers) are provided on the upper side of the GND pattern 8 as shown in FIG. 5C. By doing so, it is possible to increase the distance between each pattern of the coil L and the capacitors C _{1 to} C ₃ and the GND electrode pattern and reduce the stray capacitance.

[0015]

SUMMARY OF THE INVENTION The above-mentioned conventional device has the following problems. (1) For example, when the circuit of the high frequency filter shown in FIG. 5A is mounted on a multilayer substrate, it is necessary to have a structure that is strong against an external electric influence. Therefore, as shown in FIG. 5B, it is conceivable to form a coil and a capacitor inside the multilayer substrate and provide GND electrode patterns on the front and back surfaces of the multilayer substrate.

However, such a structure is difficult to realize because the amount of unnecessary stray capacitance increases and the input / output impedance shift and the resonance frequency shift occur. (2) In order to solve the above-mentioned point (1), as shown in FIG. 5C, the insulating layer is thickened to form a coil, a capacitor, and a GND.
It is also conceivable to separate the electrode patterns.

However, in this case, the number of layers of the multilayer substrate becomes extremely large, and the multilayer substrate becomes extremely thick. In this way, an extremely thick multilayer substrate is difficult to make, and de-binding (removing binder) during firing is also difficult.

That is, since the number of stacking steps is large, the number of stacking steps is large, so that the process time is increased and the number of failures (number of times) due to stacking deviation is increased. Further, in the debying step, it is necessary to take a long debying time (keeping at a specific temperature) as the number of substrates increases, and swelling of the substrate often occurs due to the residual binder.

The present invention solves such a conventional problem, and prevents the input / output impedance shift and the resonance frequency shift from occurring by setting the GND electrode pattern, thereby facilitating the manufacturing. To aim.

[0020]

In order to solve the above-mentioned problems, the present invention has the following constitution. (1) A high frequency filter in which at least a capacitor having a GND electrode is built in a multilayer substrate, and a GND electrode pattern which constitutes a GND side electrode of the capacitor,
The other element is provided on the outer layer of the multilayer substrate, and the other element is provided on the inner layer of the GND electrode pattern.
Shielded with an electrode pattern.

(2) The GND electrode pattern is provided on a layer on one side outside the multilayer substrate to shield one side of the multilayer substrate. (3) The GND electrode patterns are provided on both outer layers of the multilayer substrate to shield both sides of the multilayer substrate.

[0022]

The operation of the present invention based on the above construction will be described. Since the filter element built in the multi-layer substrate is easily influenced by the electric power from the outside, a GND electrode is set on one side or both sides of the multi-layer substrate to perform shielding.

In this case, according to the present invention, the shield GN is used.
The D electrode is used as the GND side electrode of the capacitor. Therefore, the deviation of the input / output impedance and the deviation of the resonance frequency are reduced.

Further, it becomes possible to arrange the circuit elements in the laminating direction of the multi-layer substrate, and the circuit elements can be formed on the circuit elements. Therefore, the lateral (horizontal) space filter is improved. Furthermore, since it is not necessary to provide an insulating layer between the GND electrode and another element, the number of laminated layers of the multilayer substrate can be small and manufacturing is easy.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. (Description of First Embodiment) FIGS. 1 and 2 are views showing a first embodiment of the present invention. FIG. 1 is an exploded perspective view of a high frequency filter, and FIG. 2 is a sectional view and a perspective view of the high frequency filter. (Surface mount component).

In the figure, the same symbols as in FIG. 5 indicate the same components.
Further, 10-1 to 10-5 are each layer (dielectric layer) of the multilayer substrate, 10-1 is a first layer, 10-2 is a second layer, 1
Reference numeral 0-3 indicates the third layer, 10-4 indicates the fourth layer, and 10-5 indicates the fifth layer.

Further, 11 to 14 are capacitor electrode patterns, 15 and 16 are coil patterns, and 17 is a GND electrode pattern. In the first embodiment, the GN is provided on one side of the multilayer substrate.
This is an example in which a capacitor having a D potential is arranged, and the circuit of the high frequency filter is the same as that of the conventional example (low-pass filter) shown in FIG. 5A.

In this example, the multilayer substrate is composed of five layers, and the capacitor having the GND electrode is arranged in the lower layer of the figure. Then, the configuration is such that the electrical influence from the lower side of the drawing is prevented.

As shown, the first layer 10-1 of the multilayer substrate
No patterning is performed on the second layer 10-2, and
Capacitor electrode pattern 11 and coil pattern 15
Is integrally formed as a thick film conductor pattern (printing pattern).

The capacitor electrode pattern 12 and the coil pattern 16 are integrally formed as a thick film conductor pattern on the third layer 10-3, and the capacitor electrode patterns 13 and 14 are formed on the fourth layer 10-4. It is formed as a thick film conductor pattern.

On the fifth layer 10-5, GND is formed on almost the entire surface.
The electrode pattern (solid GND pattern) is formed as a thick film conductor pattern. Further, the through-hole electrode 18 is formed on the third layer 10-3.

The coil patterns 15 and 16 and the capacitor electrode patterns 12 and 14 (indicated by dotted lines) are connected by blind through holes (through holes filled with conductors), and the capacitor electrode patterns 11 and 13 are connected. The spaces (indicated by the dotted lines) are connected by blind through holes via the through hole electrodes 18.

Further, one end of the capacitor electrode pattern 14 is drawn out and connected to the input terminal IN, one end of the capacitor electrode pattern 13 is drawn out and connected to the output terminal OUT, and one end of the GND electrode pattern 17 is drawn out to GND.
Connect to terminals (see Figure 2B).

The above-mentioned input terminal IN, output terminals OUT, G
External terminals such as ND terminals are provided on the side surfaces of the multilayer substrate as shown in FIG. 2B, and are surface-mounted components. In the above structure, the coil patterns 15 and 16 form a coil L, the capacitor electrode pattern 14 and the GND electrode pattern 17 form a capacitor C ₁ , and the capacitor electrode pattern 13 and the GND electrode pattern 17 form a capacitor C ₂ . Constitute.

Further, the capacitor electrode patterns 11 and 12
By configuring the configured capacitor C _31, the capacitor C ₃ in the constructed capacitor C ₃₂ by the capacitor electrode patterns 12 and 13 _{(C 3 = C 31 + C} 32).

In this way, the GND electrode pattern 1
The shield by 7 can prevent electrical influence from the lower side, and since the GND electrode pattern 17 serves as a capacitor electrode, unnecessary stray capacitance unlike the conventional case does not occur.

In the case of an SMD (surface mount component) such as the finished product of the first embodiment of the present application (FIG. 2-B), the GND electrode side is the motherboard because the pattern is easily affected by the motherboard side to be mounted (mounted). If it is mounted on the side, it can be operated in the same manner as the conventional example without being affected by the above.

(Explanation of the Second Embodiment) FIG. 3 is an exploded perspective view of a high frequency filter in the second embodiment, and FIG. 4 is a sectional view and a perspective view of the high frequency filter.

In the figure, the same symbols as in FIG. 5 indicate the same components.
Further, 20-1 to 20-6 are layers (dielectric layers) of the multilayer substrate, 20-1 is a first layer, 20-2 is a second layer, and 2-2.
0-3 is the third layer, 20-4 is the fourth layer, and 20-5 is the fifth layer.
Layer 20-6 indicates the sixth layer. Furthermore, 21 and 26 are GN
D electrode patterns, 22, 23, 24 and 25 are capacitor electrode patterns, 27 and 28 are coil patterns, and 29 is a through hole electrode.

In the second embodiment, GND is provided on both sides of the multilayer substrate.
This is an example of arranging a capacitor having a potential, and the circuit of the high frequency filter is the same as the conventional example shown in FIG. 5A (low-pass filter).

In this example, the multi-layer substrate is composed of 6 layers, the capacitor C ₁ is arranged on the upper side of the figure, and the capacitor C ₁ is arranged on the lower side.
By arranging ₂ , the structure is shielded in both upper and lower directions in the figure.

As shown, the first layer 20-1 of the multilayer substrate
A GND electrode pattern (solid GND pattern) 21 is formed on almost the entire surface, and a capacitor electrode pattern 22 is formed on almost the entire surface on the second layer 20-2.

A capacitor electrode pattern 23 and a coil pattern 27 are formed on the third layer 20-3, and the fourth layer 20-3 is formed.
Similarly, on -4, the capacitor electrode pattern 24 and the coil pattern 28 are formed.

A capacitor electrode pattern 25 is formed on almost the entire surface of the fifth layer 20-5, and a GND electrode pattern 26 (solid GND pattern) 26 is formed on the entire surface of the sixth layer 20-6. .. In addition, each of the above patterns,
All are formed as thick film conductor patterns.

Then, between the capacitor electrode pattern 22 and one end of the coil pattern 27, between the other end of the coil pattern 27 and one end of the coil pattern 28, and between the other end of the coil pattern 28 and the capacitor electrode pattern 25 (see FIG. The dotted lines) are connected by blind through holes.

Further, the capacitor electrode patterns 22, 24
And the capacitor electrode patterns 23 and 25 (dotted line portions in the drawing) are connected by blind through holes via through hole electrodes 29, respectively.

Further, one ends of the GND electrode patterns 21 and 26 are drawn out and connected to the GND terminal, one end is drawn out to the capacitor electrode pattern 22 and connected to the input terminal IN, and one end of the capacitor electrode pattern 25 is drawn out to the output terminal. Connect to OUT.

The above-mentioned input terminal IN, output terminals OUT, G
As shown in FIG. 4B, the ND terminal is provided as an external terminal on the side surface of the multilayer substrate to be a surface mount component. With the above configuration, the GND electrode pattern 21 and the capacitor electrode pattern 22 form a capacitor C ₁ , and the capacitor electrode pattern 25 and the GND electrode pattern 26 form a capacitor C ₂
And the coil pattern 27, 28 constitutes the coil L.

Further, the capacitor electrode patterns 22 and 23
A capacitor C ₃₁ formed in, a capacitor C ₃₂ composed of a capacitor electrode pattern 23 and 24, capacitor C ₃₃ composed of a capacitor electrode pattern 24 and 25
And the capacitor C ₃ (C ₃ = C ₃₁ + C ₃₂ + C ₃₃ )
Make up.

In this way, the GND electrode pattern 2
Since 1 shields the upper side and GND electrode pattern 26 shields the lower side, it is possible to prevent electrical influences from both upper and lower directions.

Moreover, in this case, the GN for shielding
The D electrode patterns 21 and 26 are electrodes of the capacitor (GN
It is used as an electrode at D potential). Therefore, the generation of unnecessary stray capacitance as in the conventional case is eliminated.

(Other Embodiments) The embodiments have been described above, but the present invention can be implemented as follows. (1) Not only the low-pass filter having a single-stage configuration shown in FIG. 5A, but an LC filter having a capacitor having a GND potential as its constituent element may be BPF (bandpass), H
PF (High Pass), BEF (Band Elimination)
Etc. can be applied to any filter.

(2) Not limited to the surface-mount type high frequency filter as in the above embodiment, it may be an insertion part using a lead frame. (3) The capacitance of the capacitor that constitutes the filter may be obtained by thinning the layers, using a high dielectric material, or partially forming a multilayer so as to obtain a predetermined capacitance.

[0054]

As described above, the present invention has the following effects. (1) Even if a GND electrode for shielding is set on one side or both sides of the filter element built in the multilayer substrate, this GND electrode is a capacitor electrode,
Unlike the conventional example, unnecessary stray capacitance does not occur. Therefore, the deviation of the input / output impedance and the deviation of the resonance frequency are small, which facilitates the design of the high frequency filter.

In the case of shielding by GND from one side, by mounting the GND side on the motherboard side when SMD is used, the influence from the circuit pattern of the motherboard can be sufficiently taken as in the conventional example. Shielding by GND from both sides is more reliable, and the upper and lower surfaces of the component are not subject to the restrictions as in the conventional example.

(2) Since the constituent elements of the high frequency filter can be arranged in the stacking direction of the multi-layer substrate, the size can be easily reduced. (3) Since it is not necessary to provide a layer for reducing the stray capacitance as in the conventional example (FIG. 5C), the number of layers of the multilayer substrate can be small and the component can be thin. Therefore, it is possible to easily remove the binder (remove the binder) in a short time, which facilitates the production.

(4) Since the circuit element can be arranged in the laminating direction of the multilayer substrate, the circuit element can be formed on the circuit element. Therefore, it becomes easy to take a space file in the horizontal direction (horizontal direction).

For example, in the above-mentioned conventional example, the coil is constituted by 3 turns, but in the embodiment of the present invention, the coil diameter can be increased and the coil can be constituted by 2 turns. Therefore, it is possible to configure with a small number of laminated layers, which facilitates manufacturing.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a high frequency filter according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a high frequency filter in the embodiment of FIG.

FIG. 3 is an exploded perspective view of a high frequency filter according to a second embodiment.

FIG. 4 is a diagram showing a high frequency filter according to a second embodiment.

FIG. 5 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 10-1 to 10-5 Each layer (dielectric layer) of multilayer substrate 11 to 14 Capacitor electrode pattern 15, 16 Coil pattern 17 GND electrode pattern 18 Through hole electrode

Claims (3)

[Claims] 1. A high frequency filter having at least a capacitor (C ₁ , C ₂ ) having a GND side electrode built in a multilayer substrate, wherein the GND side electrode of the capacitor (C ₁ , C ₂ ) is formed. A high frequency filter characterized in that an electrode pattern is provided on an outer layer of a multi-layer substrate and another element is provided on an inner layer of the GND electrode pattern and shielded by the GND electrode pattern. 2. The high-frequency filter according to claim 1, wherein the GND electrode pattern (17) is provided on a layer (10-5) on one side outside the multilayer substrate, and one side of the multilayer substrate is shielded. .. 3. The GND electrode pattern (21, 26)
On both sides of the multilayer substrate (20-1, 20-
6. The high frequency filter according to claim 1, wherein the high frequency filter is provided in 6) and both sides of the multilayer substrate are shielded.