JP2563199Y2 - Multilayer type high frequency filter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated high-frequency filter used for a high-frequency voltage-controlled oscillator or the like.

[0002]

2. Description of the Related Art High-frequency filters are used as mobile radio devices such as automobile phones, various radio devices such as mobile phones, or components such as voltage-controlled oscillators incorporated therein. Used. The conventional high-frequency filter used for such an application has a structure in which a magnetic material is not used as a core material, a dielectric material such as plastic or ceramic is used, and a conductor electrode is applied or electroplated on the dielectric material. .

[0003] However, in this conventional filter, since the electrodes are exposed to the outside, special treatment such as coating the surface with a resin or the like to prevent oxidation of the electrodes or contact with other components during mounting is performed. And there is a problem that it takes a lot of man-hours.

Therefore, it is conceivable that an inductor and a capacitor are formed by stacking a coil structure and an electrode together with an insulator to form a distributed constant filter or a lumped constant filter. However, the microstrip line, which is a distributed constant filter, has the advantage of obtaining steep characteristics (high Q) and small insertion loss, but it has to be reduced to one quarter of the wavelength that handles the length of the transmission line. However, there is a disadvantage that the shape becomes large. On the other hand, since the lumped filter can be designed with a length sufficiently shorter than the wavelength to be handled, it can be miniaturized. However, it has disadvantages in that a steep characteristic cannot be obtained (poor Q) and insertion loss is large.

According to the present invention, a relatively high Q can be obtained, and
It is an object of the present invention to provide a laminated high-frequency filter that can be reduced in thickness .

[0006]

In order to achieve this object, the present invention provides a dielectric, a ground electrode and a strip line.
Distribution by microstrip line with multilayer structure
Constant filter, dielectric, coil conductor and internal electrode
Inductor and multilayer capacitor with multilayer structure
Integrated with a lumped filter composed of parallel circuits
And the distributed constant filter and the lumped constant filter
Data sets the resonant frequency about the same, the distributed constant Fi
Part of the Luta stripline and the lumped parameter fill
A part of the conductor of the capacitor with a dielectric layer
The distributed constant filter and the lumped filter
It is characterized in that it is combined with a number filter (claim 1). Also, the present invention combines two strip lines.
A set of distributed constant filters and two lumped constant filters
Filter and a set of lumped constant filters
And characterized in that (claim 2).

[0007]

The filter according to the present invention has the above-mentioned structure, and prevents a decrease in Q by using a distributed constant filter and prevents an increase in thickness by using a lumped constant filter.

[0008]

1A is a perspective view showing an embodiment of a laminated high-frequency filter according to the present invention, FIG. 1B is an equivalent circuit diagram thereof, and FIG. 1C is a characteristic diagram thereof. In FIG. 1A,
1 is a dielectric made of ceramic, 2 is an input terminal electrode formed by baking or electroplating on one side of the dielectric 1, 3 is an output terminal electrode, 4 is a terminal electrode for connection between internal conductors, 6 ground terminal The electrodes are made of silver or silver-palladium. In this filter, a multi-stage filter is formed by integrally laminating a distributed constant filter 7 having a laminated structure composed of microstrip lines and a lumped constant filter 8 having a laminated structure. FIG.
Reference numerals 7 and 8 in (B) denote circuit configurations of a distributed constant filter and a lumped constant filter, respectively.

FIGS. 2 and 3 are views showing the manufacturing process of the filter of this embodiment. The following shows the steps in a printing method, but a manufacturing method such as a sheet method can be appropriately selected. First, as shown in (a), after printing the dielectric 1a, one ground electrode 10 is printed as shown in (b). Next, as shown in (c), a dielectric 1b is printed on the entire surface, and a strip line 11 is printed thereon as shown in (d). Next, as shown in (e), the dielectric 1c is printed on the entire surface, and as shown in (f),
The strip line 12 is printed. Stripline 1
Reference numeral 2 denotes a position where the main part does not face the strip line 11, and the projecting parts 11c and 12c provided integrally with the strip lines 11 and 12 respectively face each other via the dielectric 1c.

[0010] Next, as shown in FIG.
d is printed thereon, and the terminal electrode 2 is printed thereon as shown in FIG.
The ground electrode 13 is printed except for the sides 4 to. Then, a dielectric 1e is printed on the entire surface as shown in (i), and capacitor forming internal electrodes 14 and 15 are formed thereon. After the dielectric 1f is printed on the entire surface as shown in (k), the ground electrode 16 is printed. Then, after printing 1 g of a dielectric material on the entire surface as shown in (l), after printing lead electrodes 17 and 18 of the coil conductor as shown in (m),
As shown in (n), a dielectric 1h is printed so as to cover a half surface of each of the coil conductors 17 and 18, and a part thereof is overlapped on each of the coil conductors 17 and 18 as shown in (o). Then, the coil conductors 19 and 20 are printed.

Next, as shown in FIG. 3A, a dielectric 1i is printed so as to cover a half surface of each of the coil conductors 19 and 20, and a part of each of the dielectrics 1i overlaps with each of the coil conductors 19 and 20. As described above, the coil conductors 21 and 22 are printed. Then (b)
As shown in (c), the dielectric 1j is printed so as to cover a half surface of each of the coil conductors 21 and 22, and as shown in FIG. The electrodes 23 are printed. Next, as shown in (d), the dielectric 1k is printed on the entire surface, and as shown in (e), the shielding ground electrode 24 (this is not necessarily required) is printed. Next, a dielectric 1m is printed on the entire surface as shown in FIG.

After firing, the terminal electrodes 2 to 4 and 6 are baked or electroplated as shown in FIG. Here, the input terminal electrode 2 is connected to one end 11b of the strip line 11, the output terminal electrode 3 is connected to the end 18a of the lead electrode 18 of the coil conductor and the end 15a of the internal electrode 15, and the terminal electrode 4 is Internal electrode 1
4 and the end 17 a of the lead electrode 17. The ground terminal electrode 6 is connected to the ground electrodes 10, 1
Ends 10a, 13a, 16a, 24 of 3, 16, 24
a and each end 11a, 1
2a and the lead electrode end 23a of the coil conductor.

In FIG. 1B, the inductances L1 and L2 are formed by the strip lines 11 and 12, and the inductance L3 is the coil conductors 17, 19 and 2.
1, 23, the inductance L4 is formed by the coil conductors 18, 20, 22, 23, the capacitor C1 is formed between the strip line 11 and the ground electrode 10, and the capacitor C2 is formed between the strip line 12 and the ground electrode 13. And the capacitor C3 is connected to the electrode 1
4, a capacitor C4 is formed between the electrode 15 and the ground electrodes 13, 16, and a capacitor C5 is formed between the strip line 1 and the ground electrodes 13, 16.
The capacitor C6 is formed between the protrusions 12c of the strip line 12 and the portion 14b of the electrode 14.

As shown in FIG . 1C, a distributed constant filter 7 composed of strip lines 11 and 12 is
The lumped-constant filter 8 composed of a layer inductor and a multilayer capacitor has dimensions and materials such that the resonance frequencies are substantially the same.
Quality is set, but compared when these are configured alone
Then, as in the present invention, both filters are superimposed and electrically connected.
By doing so, a characteristic closer to the distributed constant filter, that is, a loss reduced and steepened characteristic can be obtained as compared with a case where a multi-stage filter having the same number of stages is constituted only by the lumped constant filter. Further, for example, when the relative dielectric constant of the dielectric 1 is 10 at 800 MHz, the strip line 1
Although the length of the coils 1 and 12 is about 2.5 cm, the coil composed of 17 to 23 can be constituted by a helical coil having a side length of about 1 mm in the case of a helical coil as in the embodiment. A lumped-constant filter can be configured in multiple stages within the length of the line, and the thickness can be reduced as compared with a multi-stage filter using only strip lines. Also, as in this embodiment, two
Set of strip lines 11 and 12
Combining the cloth constant filter 7 and two lumped constant filters
And a set of lumped constant filters 8
Distributed filter consisting of one strip line
Compared to the case of combining with one lumped filter,
Further, a filter having steep frequency characteristics can be obtained.

The coil conductors 17 to 2 serving as transmission lines
3 and the ground electrodes 10, 13, 16, and 24 are buried in the dielectric 1, so that the coil conductor and the ground electrode are oxidized and the coil conductor and the ground electrode come into direct contact with other components during mounting. Without these damages. In addition, since the coil conductor and the ground electrode are protected in the intermediate product, handling during the manufacturing process becomes easy. In addition, since the coil conductor and the ground electrode are protected by the dielectric itself, a special process such as coating the surface with a resin is not required, the number of steps is reduced, and the device can be easily manufactured.

Further, on this laminated high frequency filter,
It is also possible to configure a wiring pattern or a resistor network by thick film printing, mount an IC or a transistor thereon, and apply it as a hybrid integrated circuit element.

[0017]

According to the first aspect of the present invention , since the distributed constant filter using the microstrip line and the lumped constant filter of the multilayer inductor and the multilayer capacitor are integrally formed, compared with the filter constituted only by the lumped constant filter. A multi-stage filter having a high Q and a reduced loss can be obtained, and the thickness can be reduced as compared with a filter constituted only by a distributed constant filter. According to claim 2, two switches are provided.
A set of distributed constant filters combining trip lines
And a set of lumps formed by combining two lumped constant filters
By combining with a constant filter, the steepness
A filter having wave number characteristics is obtained.

[Brief description of the drawings]

1A is a perspective view showing an embodiment of a multilayer high-frequency filter according to the present invention, FIG. 1B is an equivalent circuit diagram of the embodiment, and FIG. 1C is a diagram showing the relationship between the frequency and the amount of attenuation. .

FIG. 2 is a process chart showing a part of the manufacturing process of the present embodiment.

FIG. 3 is a process chart showing the rest of the manufacturing process of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a-1m Dielectric 2 Input terminal electrode 3 Output terminal electrode 4 Terminal electrode 6 Ground terminal electrode 7 Distributed constant filter 8 Lumped constant filter 10, 13, 16, 24 Ground electrode 11, 12 Strip line 14, 15 Internal electrode 17 -23 coil conductor

Claims (2)

(57) [Scope of request for utility model registration] 1. The method of claim 1, wherein the dielectric, the ground electrode, and the strip line
Distribution determination using a microstrip line with a laminated structure
Filter and the dielectric, coil conductor and internal electrode
Of multilayer inductors and multilayer capacitors
Lumped constant filter composed of parallel circuit integrated
And the distributed constant filter and the lumped constant filter
The wave numbers are set to be substantially the same, and a part of the strip line of the distributed
A part of the lumped-constant filter conductor and the dielectric layer
By facing and capacitively coupling, the distributed constant
And a lumped filter combined with a filter. 2. The method according to claim 1, A set of distributed constants formed by combining two strip lines
1 consisting of a filter and two lumped constant filters
Product characterized by combining a set of lumped constant filters
Layered high frequency filter.