JP2950201B2 - Electronic component including parallel resonator of inductor and capacitor and frequency adjustment method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of adjusting the frequency of a filter including a parallel resonator of an inductor and a capacitor, and more particularly to a filter having a multilayer structure and a filter having such an adjustment.

[0002]

2. Description of the Related Art Frequency adjustment of an electronic component having a laminated structure including a parallel resonator of an inductor and a capacitor is possible by trimming an inductor electrode or a capacitor electrode exposed or closest to an outer surface. It can be said that it is desirable to trim the capacitor electrode in order to avoid deterioration of the Q characteristic.

By the way, the frequency adjustment of the resonator does not require a very wide range, and it is usually sufficient to adjust the deviation from the standard of the resonance frequency due to a manufacturing error. However, in the method of removing the electrodes by trimming, there is a possibility that the entire target electrode may be removed. In such a case, there is a problem that the configuration of the resonator is lost beyond the necessary resonance frequency adjustment range.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a useful method and a filter having such a configuration that can suppress the adjustment of the resonance frequency within a required range even if all the electrodes are trimmed and removed.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method for adjusting the frequency characteristics of a filter including a resonator comprising an inductor and a resonator capacitor connected in parallel to the inductor, wherein the inductor comprises a printed coil. The capacitor is divided into a plurality of parts, each of the divided capacitors is connected in parallel to the inductor, and the electrode of one divided capacitor is arranged between the pair of shield electrodes together with the printed coil, and One of the electrodes of the divided capacitor is disposed outside the shield electrode as a trimming electrode, and the capacitance is obtained by using the shield electrode as the other electrode to adjust the frequency characteristics of the filter by trimming the trimming electrode. It is characterized by the following.

A filter including a resonator comprising an inductor and a resonator capacitor connected in parallel to the inductor, wherein the inductor is constituted by a printed coil, and the capacitor is divided into a plurality of parts,
Each of the divided capacitors is connected in parallel to the inductor, an electrode of one divided capacitor is disposed between the pair of shield electrodes together with the printed coil, and one of the electrodes of the other divided capacitor is used as a trimming electrode. It is arranged outside the shield electrode, obtains a capacitance by using the shield electrode as the other electrode, and adjusts frequency characteristics by trimming the trimming electrode.

[0007]

According to the present invention, the capacitor as a component of the parallel resonator is divided into a plurality of capacitors, and the electrode of one of the capacitors is trimmed and removed.
Even if all the electrodes are trimmed, the configuration of the parallel resonator remains with the remaining capacitor electrodes and inductors. Therefore, the range in which the frequency can be adjusted by trimming is limited.

[0008]

FIG. 2 is an exploded perspective view showing a bandpass filter to which the frequency adjusting method of the present invention is applied, and FIG. 3 is a front sectional view thereof. This filter is formed by appropriately laminating a green sheet made of an unfired dielectric or the like, and an electrode layer made of a conductive material formed on one side of the green sheet by printing or the like, and the side surface is also made of a conductive material. It is manufactured by firing a connection terminal formed by printing or the like.

A protective layer 1 is formed at the lowermost part in the thickness direction,
On top of that, the shield electrode layers 2a and 2b, the dielectric layer 3,
Print coil 4 (comprising 4a, 4b, 4c), dielectric layer 5, pole forming capacitor electrode layer 6, capacitor forming layer 7, input / output impedance adjusting capacitor electrode layers 8a, 8b, input / output impedance adjusting capacitor forming Layer 9, first capacitor electrode layer for resonance circuit 10a, 1
0b, capacitor forming layer 11 for resonance circuit, shield electrode layers 12a and 12b, capacitor forming layer 1 for frequency adjustment
3, the second capacitor electrode layers 14a and 14b for the resonance circuit,
The protective layer 15 is sequentially formed, and connection terminals 16a to 16h having eight U-shaped cross sections are formed on side surfaces. That is, in this filter, the protection layer 15 is formed on the second capacitor electrode layers 14a and 14b for the resonance circuit in advance when the filter is manufactured.

[0010] As shown in FIG.
It has three printed coils 4a, 4b, 4c, and both ends of two printed coils 4a, 4b for the resonance circuit are connected to hot (input / output) connection terminals 16b, 16c and ground connection terminals 16e, 16h, respectively. The two printed coils 4a and 4b are coupled with the degree of magnetic coupling M with the hot side approaching, and the ground side is connected with the pole-formed printed coil 4c.

The shield electrode layers 12a and 12b on the upper side of the print coil 4 are separated from each other as shown by the solid line in FIG. Are opposed to the shield electrode layers 12a and 12b as shown by broken lines in FIG. One resonance circuit first capacitor electrode layer 10a is connected to an input connection terminal 16b to which one end of the printed coil 4a is connected, and the shield electrode layer 12a facing the capacitor electrode layer 10a is connected to the other end of the printed coil 4a. The ground connection terminal 16e is connected to the first side for the resonance circuit because the resonance circuit capacitor forming layer 11 made of a dielectric is interposed between the two electrode layers 12a and 10a.
A capacitor C2 is formed. On the other hand, the second capacitor electrode layer 14a for the resonance circuit is opposed to the shield electrode layer 12a via the capacitor formation layer 13 for frequency adjustment to form the second capacitor C2x for the resonance circuit,
The second capacitor electrode layer 14a serves as the input / output connection terminal 1
Since the first capacitor electrode layer 10a is connected to the first capacitor electrode layer 10a via the second capacitor 6b, the first capacitor C2 and the second capacitor C2x for the resonance circuit are connected in parallel, and have a combined capacitance of C2 + C2x. And this capacitor C2 +
C2x and the inductor L1 formed by the printed coil 4a are connected via connection terminals 16b and 16e to form an LC resonance circuit. The resonance frequency of the LC resonance circuit is made variable by performing a trimming process on the resonance circuit second capacitor electrode layer 14a forming the resonance circuit second capacitor C2x. The shield electrode layers 2a and 2b below the printed coil 4
Is also separated from each other as shown by a solid line in FIG. 5, but it may be integrated without separating.

First capacitor electrode layer 1 for the other resonance circuit
0b is connected to an input connection terminal 16c to which one end of the printed coil 4b is connected.
b and the shield electrode layer 12b is the printed coil 4
b is connected to a ground connection terminal 16h to which the other end of the resonance circuit is connected. Between the two electrode layers 12b and 10b, a resonance circuit capacitor forming layer 11 made of a dielectric material is interposed. The first capacitor C4 is formed. Similarly, a second capacitor C4x is formed between the second capacitor electrode layer 14b for the resonance circuit and the shield electrode layer 12b, and the first capacitor electrode layer 10b and the second capacitor electrode layer 14b are connected via the input / output connection terminal 16c. Is connected, the first capacitor C4 and the second capacitor C4x are connected in parallel, and become a capacitor having a combined capacitance C4 + C4x. Then, an inductor L2 formed by the combined capacitor C4 + C4x and the printed coil 4b.
Is connected via the connection terminals 16c and 16h to the LC
A resonance circuit is formed. The resonance frequency of the LC resonance circuit is made variable by performing a trimming process on the second capacitor electrode layer 14b.

The print coil 4b forming the LC resonance circuit and the print coil 4a forming the above-described LC resonance circuit are connected by the above-described pole formation print coil 4c. Note that the inductor of the printed coil 4c is L5. Under the capacitor electrode layers 10a and 10b, which are one electrode constituting the first capacitors C2 and C4 for the resonance circuit, an L-shaped input / output impedance adjustment as shown by a dashed line in FIG. Capacitor electrode layers 8a and 8b are formed apart from each other, and between the input impedance adjusting capacitor layer 8a and the first capacitor electrode layer 10a for a resonance circuit, an input / output impedance adjusting capacitor forming layer 9 made of a dielectric is provided. Capacitor C for input impedance adjustment
1 is formed, and one input capacitor electrode layer 8a forming this capacitor is connected to the input connection terminal 16a.

On the other hand, an output impedance adjusting capacitor electrode layer 8b and a resonance circuit first capacitor electrode layer 10b
A capacitor C3 for adjusting output impedance is formed via an input / output impedance adjusting capacitor forming layer 9 made of a dielectric material, and one output capacitor electrode layer 8b forming this capacitor C3 is connected to an output connection. Connected to terminal 16d.

Below the input / output impedance adjusting capacitor electrode layers 8a and 8b, one pole forming capacitor electrode layer 6 is formed via a capacitor forming layer 7, and both sides of the capacitor electrode layer 6 are formed. Are opposed to the capacitor electrode layers 8a and 8b, and pole-forming capacitors C5 and C5 are formed. Accordingly, the input / output capacitor electrode layers 8a and 8b are connected to the capacitors C5 and C5 formed between both ends of the pole forming capacitor electrode layer 6.
The connection is made at the pole forming capacitor electrode layer 6 via C5.

Accordingly, the band-pass filter having the above-described configuration includes an inductor L1 and a capacitor C2 + as shown in FIG.
A first LC resonance circuit Q1 composed of C2x and a second LC resonance circuit Q2 composed of an inductor L2 and a capacitor C4 + C4x form a magnetic coupling degree M between the inductors L1 and L2.
And a hot input / output connection terminal side between the two resonance circuits Q1 and Q2.
Specifically, in this example, a pole forming capacitor C is provided between the input and output impedance adjusting capacitors C1 and C3.
5 are connected in parallel, and two resonance circuits Q1, Q
The circuit configuration is such that a pole forming inductor L5 is connected between the two ground connection terminals. L3 and L4 are the inductance of the ground connection terminal 16e connected to the shield electrode layer 12a and the inductance of the ground connection terminal 16h connected to the shield electrode layer 12b.

FIG. 7 is a frequency characteristic diagram of the band-pass filter having this configuration. The frequency characteristics of the band-pass filter include the pole forming inductor L5 and the pole forming capacitor C5.
Paul due to the presence of on both sides of the center frequency f ₀ P1, P2
Is formed. Note that the solid line indicates the attenuation rate, and the broken line indicates the insertion loss. Next, a method of adjusting the frequency of the bandpass filter configured as described above will be described. The target of trimming in this filter is the above-mentioned second capacitor electrode layers 14a and 14b for a resonance circuit.
In the method of the present invention, the second capacitor electrode layer 14
This is a method of trimming and removing a and 14b together with the upper protective layer 15.

When trimming is performed in this manner, even if sand blasting is used for trimming, as shown in FIG. 1, there is a protective layer 15 having a property that it does not easily extend over the second capacitor electrode layers 14a and 14b. Therefore, the second capacitor electrode layers 14a and 14b thereunder also become difficult to extend,
Therefore, the cut surface (the processed bottom surface and side surface) is in a beautiful state without irregularities. As a result, accurate trimming becomes possible.

FIG. 8 shows the second capacitor electrode layers 14a, 1
FIG. 7B is a frequency characteristic diagram showing the case where all of 4b is trimmed (solid line is attenuation factor, broken line is insertion loss), and the center frequency f ₀ can be raised by about 26 MHz from the state of FIG. 7 by trimming. Since the amount of increase of the center frequency f ₀ changes in accordance with the trimming area of the capacitance forming electrode layers 14a and 14b, in the case of this filter, the maximum trimming area is changed to about 26 MHz by changing the trimming area. The frequency can be accurately adjusted within that range.

[0020]

[0021]

In the above embodiment, sand blast is taken as an example of means for performing trimming. However, the means applicable to the present invention is not limited to this. Trimming is possible. However, when using a laser or the like,
It is necessary to slightly increase the depth of the trimming process.

In the above embodiment, trimming is performed on an electronic component having a protective layer formed outside the second capacitor electrode. However, the present invention is not limited to this.
When the capacitor electrode is an exposed outermost layer, a protective layer made of a dielectric may be formed thereon and trimming may be performed. Further, the material of the protective layer is not limited to a dielectric, and a general ceramic material may be used. In the case where a ceramic layer such as a protective layer is formed outside the second capacitor electrode as in the present invention, it is possible to prevent the second capacitor electrode from peeling off in a barrel process in manufacturing a resonator or a filter. There is an advantage that can be done.

As described above, according to the present invention,
The capacitor is formed by a plurality of divided capacitors, one of the divided capacitors is trimmed, and the capacitor electrode forming the trimmed capacitor is positioned outside the grounded shield electrode layer. Since the frequency adjustment is performed in this manner, the frequency adjustment range can be suppressed to a required range, and the frequency can be finely adjusted by appropriately determining the area of the electrode to be trimmed and the interval between the counter electrodes. effective.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a portion trimmed according to the present invention.

FIG. 2 is a plan view showing a bandpass filter to which the method of the present invention is applied.

FIG. 3 is a front sectional view of a bandpass filter to which the method of the present invention is applied.

FIG. 4 is a plan view mainly showing an inductor portion of a bandpass filter to which the method of the present invention is applied.

FIG. 5 is a plan view showing a capacitor part of a bandpass filter to which the method of the present invention is applied.

FIG. 6 is an equivalent circuit diagram of the filter of FIG.

FIG. 7 is a frequency characteristic diagram of the filter of FIG. 2;

8 is a frequency characteristic diagram when all the frequency adjustment capacitor electrodes of the filter of FIG. 2 are removed.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Teruhisa Tsuru 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto, Japan Inside Murata Manufacturing Co., Ltd. (72) Tetsuo Taniguchi 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto, Japan Inside Murata Manufacturing Co., Ltd. (72) Inventor Ken Ken Tonegawa 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Co., Ltd. Inside Murata Manufacturing Co., Ltd. (56) References Real Open 48-105042 (JP, U) Real Open Sho 53- 141944 (JP, U) (58) Fields studied (Int. Cl. ⁶ , DB name) H01G 4/00-4/40 H03H 5/02 H03H 7/01 H01F 15/00

Claims (2)

(57) [Claims] 1. A resonator comprising an inductor and a resonator capacitor connected in parallel to the inductor.
A method for adjusting a frequency characteristic of a filter , wherein the inductor is constituted by a printed coil, the capacitor is divided into a plurality of capacitors, and each of the divided coils is
Capacitor is connected in parallel with the inductor,
Of the split capacitor together with the printed coil
It is placed between a pair of shield electrodes and another split capacitor
One of the electrodes of the sensor is the shield as a trimming electrode.
The shield electrode is disposed outside the electrode, and the capacitance is obtained by using the shield electrode as the other electrode.
Ri, frequency of the filter by trimming the trimming electrodes
Frequency characteristics of filters characterized by adjusting characteristics
Adjustment method. 2. A resonator comprising an inductor and a resonator capacitor connected in parallel to the inductor.
A filter , wherein the inductor is constituted by a printed coil, the capacitor is divided into a plurality of coils, and each of the divided coils is
Capacitor is connected in parallel with the inductor,
Of the split capacitor together with the printed coil
It is placed between a pair of shield electrodes and another split capacitor
One of the electrodes of the sensor is the shield as a trimming electrode.
The shield electrode is disposed outside the electrode and the other electrode is
And the trimming electrode is trimmed.
That the frequency characteristics have been adjusted
Filter to mark.