JP2769115B2 - Multilayer RF transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an RF transformer used in radio equipment using microwaves.

[0002]

2. Description of the Related Art FIG. 5 is a perspective view of a conventional RF transformer. In this conventional example, a wire rod 5 is formed on a ferrite core 51 having two through holes so that the equivalent circuit shown in FIG.
2 is wound. Further, there has been proposed an inductance element in which a conductor film is formed on a magnetic material sheet, laminated, and then fired and integrated.

[0003]

In a conventional RF transformer, a thin wire is manually wound around a ferrite core, but it requires a great deal of man-hours, is difficult to mechanize, and has poor mass productivity. In addition, there was a limit to miniaturization. Even in the stacked type, it is difficult to obtain desired characteristics simply by forming a transformer by stacking conductor films. In view of the above, an object of the present invention is to provide a multilayer RF transformer that has mass productivity, has desired characteristics, and can be reduced in size.

[0004]

According to the present invention, a dielectric constant of 6 to 6 is provided.
Dielectric substrate comprising 12 dielectric materials, on the dielectric substrate
A laminate formed by laminating the conductive film formed on the substrate and the dielectric substrate
Wherein the conductor film is connected to at least four coils
Is formed, and two of the four coils are paired.
To form a transformer, and two transformers are formed.
A laminated RF transformer, comprising the transformer
The thickness of the dielectric layer between the conductor films in the portion where
m, and the thickness of the dielectric layer between the two transformers is 1
60 μm or more, 1500 MHz to 2000 MHz
In which the insertion loss is 1 dB or less.
It is an F transformer. Also, the present invention provides the transformer
One of the pair of coils is formed only on one dielectric substrate, and the other coil is formed on the upper and lower two dielectric substrates sandwiching the dielectric substrate forming the one coil. This is a multilayer RF transformer configured by connecting conductive films.

[0005]

According to the present invention, since the transformer is formed by the lamination technique, the manual winding work as in the prior art is not required, and the mass productivity is improved. Further, it has a laminated structure and can be miniaturized. In the present invention, the dielectric constant is 6 to 12
Using dielectric materials, transformer portion comprising a pair of coils, the thickness of the dielectric between the conductive film and 40 to 100 [mu] m, that have extended coupling between the coils. Also, as above 160μm the thickness of the dielectric between the two transformers of upper and lower, 2
Unnecessary coupling between individual transformers is suppressed. Further, according to the present invention, in a transformer portion composed of a pair of coils, one coil is formed on one dielectric substrate, and the other coil is formed of two upper and lower sheets sandwiching the dielectric substrate forming the one coil. The coupling between a pair of coils is enhanced as a coil configured by connecting conductor films formed on the dielectric substrate.

[0006]

FIG. 1 is a perspective view of an embodiment according to the present invention. FIG. 2 is a plan view showing the state of each dielectric substrate to be laminated in this embodiment. In this embodiment, as shown in FIG. 2, an RF transformer is formed by forming a conductor film on a dielectric substrate and laminating it. This will be described.
Using a glass-based ceramic material having a relative dielectric constant of εr = 8,
The sheet is formed by a doctor blade to obtain a dielectric green sheet (dielectric substrate). A conductive material is screen-printed on the dielectric substrate 1 made of the green sheet to form a coil conductive film 11a. One end of the coil conductor film 11a is drawn out to the side surface to form a terminal connection electrode 15a, and the other end is formed with a circular electrode 16a corresponding to a through hole. A dielectric substrate 2 made of a green sheet is laminated thereon. The dielectric substrate 2 is formed with the coil conductor film 12 and one independent through-hole electrode 17a. Both ends of the coil conductor film 12 are drawn out to the side surfaces to form terminal connection electrodes 15b and 15c, thereby forming a coil of about one turn. A dielectric substrate 3 made of a green sheet is laminated thereon. On the dielectric substrate 3, a coil conductor film 11b is formed. This coil conductor film 1
A through-hole electrode 17b is formed at one end of 1b, and a terminal connection electrode 15d is formed so as to extend to the side surface at the other end. Then, the coil conductor film 11a and the coil conductor film 1
1b is conducted through the through-hole electrodes 17b and 17a and the circular electrode 16a to form one coil. A transformer is composed of the coil and the coil formed by the coil conductor film 12. A dielectric substrate 4 serving as a dummy layer is stacked thereon without forming a conductor film. This dummy layer was composed of a plurality of green sheets. A dielectric substrate 5 made of a green sheet is laminated thereon. The dielectric substrate 5 has the coil conductor film 1
3a are formed. This coil conductor film 13a is
One end is pulled out to the side to form a terminal connection electrode 15e, and the other end is a circular electrode 16 corresponding to a through hole.
b is formed. A dielectric substrate 6 made of a green sheet is laminated thereon. This dielectric substrate 6 includes
The coil conductor film 14 and one independent through-hole electrode 17c are formed. This coil conductor film 14 is
Both ends are pulled out to the side surfaces, and the terminal connection electrodes 15f, 1
5 g, thereby forming a coil of about one turn. A dielectric substrate 7 made of a green sheet is laminated thereon. On the dielectric substrate 7, a conductor film 13b for a coil is formed. A through-hole electrode 17d is formed at one end of the coil conductor film 13b, and a terminal connection electrode 15h is formed so as to extend to the side surface at the other end. The coil conductor film 13a and the coil conductor film 13b conduct through the through-hole electrodes 17d and 17c and the circular electrode 16b to form one coil. A transformer is composed of the coil and the coil formed by the coil conductor film 14. A dielectric substrate 8 made of a green sheet is laminated thereon. The dielectric substrate 8 has conductor films 18a, 18b, 18c, 18d, 18e, 1 for terminal electrodes.
8f is formed. The laminated body was integrally fired, and the terminal electrode 19 was formed on the side surface to form a laminated RF transformer in which two transformers each including a pair of coils were vertically arranged. In FIG. 1, reference numerals 9a and 9c denote transformer sections each including a pair of coils, and 9b denotes a dummy layer. This circuit diagram is similar to FIG. In this embodiment, the thickness of the dielectric substrates 2, 3 and the dielectric substrates 6, 7 after sintering is 80 μm.
The thickness of the dielectric between the conductor films 11b and 13a after sintering was 240 μm. As a result, an RF transformer having good coupling between a pair of coils constituting each transformer and less unnecessary coupling between the upper and lower two transformers could be obtained.

FIG. 6 shows the insertion loss characteristics of the RF transformer of this embodiment. Thus, according to the embodiment of the present invention,
Insertion loss of 1 from 1500 MHz to 2000 MHz
dB or less, indicating that the loss is extremely low. FIG. 7 shows the phase characteristics between the two outputs of this embodiment. As can be seen from FIG. 7, according to the embodiment of the present invention, 500
Phase difference of 18 in a wide frequency band from MHz to 2000 MHz
0 degree, which indicates that the characteristics are excellent as an RF transformer. FIG. 3 is a plan view showing the state of each laminated dielectric substrate of another embodiment according to the present invention. In this embodiment, an RF transformer is formed by forming a conductor film on a dielectric substrate and laminating the same, as in FIG. First, a conductive material is screen-printed on a dielectric substrate 21 made of a green sheet to form a coil conductive film 31a.
Coils conductor film 31a of this has one end drawn out to the side surface, to form a terminal connection electrode 35a, the other end, circular electrodes 36a corresponding to the through holes. A dielectric substrate 22 made of a green sheet is laminated thereon. The dielectric substrate 22 includes a conductor film 32 for a coil.
a and one independent through-hole electrode 37a. One end of the coil conductor film 32a is drawn out to the side surface to form a terminal connection electrode 35b, and the other end is formed with a circular electrode 36b corresponding to a through hole. On top of that, a dielectric substrate 23 made of a green sheet is provided.
Are laminated. On the dielectric substrate 23, a coil conductor film 31b and one independent through-hole electrode 37c are formed. One end of the coil conductive film 31b is drawn out to the through-hole electrode 37b and the other end is drawn out to the side surface to form a terminal connection electrode 35c. The coil conductor film 31a and the coil conductor film 31b conduct through the through-hole electrodes 37b, 37a and the circular electrode 36a to form one coil. A dielectric substrate 24 made of a green sheet is laminated thereon. On the dielectric substrate 24, a coil conductor film 32b is formed. One end of the coil conductor film 32b is drawn out to the through-hole electrode 37d, and the other end is drawn out to the side surface to form a terminal connection electrode 35d. Then, the coil conductor film 32
a and the conductor film 32b for the coil
It conducts through the electrodes d and 37c and the circular electrode 36b to form one coil. This coil and the conductor film 3 for the coil
A transformer is composed of the coils 1a and 31b. A dielectric substrate 25 serving as a dummy layer is laminated thereon without forming a conductor film. This dummy layer was composed of a plurality of green sheets. A dielectric substrate 26 made of a green sheet is laminated thereon. On the dielectric substrate 26, a coil conductor film 33a is formed. Coils conductor film 33a of this has one end drawn out to the side surface, to form a terminal connection electrode 35e, the other end, circular electrode 36c corresponding to the through holes. On top of this, a dielectric substrate 27 made of a green sheet
Are laminated. On the dielectric substrate 27, a coil conductor film 34a and one independent through-hole electrode 37e are formed. One end of the coil conductor film 34a is drawn out to the side surface to form a terminal connection electrode 35f, and the other end is formed with a circular electrode 36d corresponding to a through hole. A dielectric substrate 28 made of a green sheet is laminated thereon. The dielectric substrate 28 has a coil conductor film 33b and one independent through-hole electrode 37g.
Are formed. One end of the coil conductor film 33b is drawn out to the through-hole electrode 37f and the other end is drawn out to the side surface to form a terminal connection electrode 35g. The coil conductor film 33a and the coil conductor film 33b conduct through the through-hole electrodes 37f and 37e and the circular electrode 36c to form one coil. A dielectric substrate 29 made of a green sheet is laminated thereon. On the dielectric substrate 29, a coil conductor film 34b is formed. One end of the coil conductor film 34b is drawn out to a side hole electrode 37h and the other end is drawn out to a side surface to form a terminal connection electrode 35h. The coil conductive film 34a and the coil conductive film 34b conduct through the through-hole electrodes 37h and 37g and the circular electrode 36d to form one coil. A transformer is constituted by the coil and the coil formed by the coil conductor films 33a and 33b. A dielectric substrate 30 made of a green sheet is laminated thereon. This dielectric substrate 30 has conductor films 38a, 38b, 38c, 38d, 38e for terminal electrodes.
38f are formed. The laminated body was integrally fired, and terminal electrodes were formed on the side surfaces to form a laminated RF transformer in which two transformers each composed of a pair of coils were vertically arranged. The appearance of this embodiment is the same as that of FIG.
It is the same as FIG. In this embodiment, the dielectric substrate 22,
The sintered thickness of the dielectric substrates 23, 24 and the dielectric substrates 27, 28, 29 was 80 μm, and the sintered dielectric thickness between the conductor films 32b and 33a was 240 μm. This allows
An RF transformer having good coupling between a pair of coils constituting each transformer and less unnecessary coupling between the upper and lower two transformers could be obtained. R of this embodiment
The F transformer was able to obtain the same characteristics as those of the above-described embodiment. In the above embodiment, the thickness of the dielectric between the conductor films in the pair of coil portions was set to 80 μm.
If so, the binding was good. Further, in the pair of coil portions, conductor films constituting each coil were alternately formed, which also improved the coupling. In the above embodiment, the thickness of the dielectric between the upper and lower transformers was 240 μm. However, when the thickness was 160 μm or more, unnecessary coupling between the transformers could be suppressed. The dielectric constant of the dielectric material used in the present invention is preferably 6 to 12 .

[0008]

According to the present invention, since the RF transformer is composed of a laminated body, the winding of the transformer does not need to be performed manually and automation can be achieved, so that the mass production is excellent. In addition, the distance between the conductor films forming the pair of coils and the distance between the upper and lower transformers are specified, and the distance between the conductor films is determined .
By specifying the electric power, 1500 MHz to 2000
MHz, the insertion loss of which is less than 1 dB
Thus, a laminated RF transformer can be constructed.

[Brief description of the drawings]

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

FIG. 2 is a plan view of a dielectric substrate to be laminated according to an embodiment of the present invention.

FIG. 3 is a plan view of a dielectric substrate to be laminated according to another embodiment of the present invention.

FIG. 4 is an equivalent circuit diagram of an RF transformer.

FIG. 5 is a perspective view of a conventional example.

FIG. 6 is an insertion loss characteristic diagram of one embodiment according to the present invention.

FIG. 7 is a phase characteristic diagram of one embodiment according to the present invention.

[Explanation of symbols]

1,2,3,4,5,6,7,8,21,22,23,
24, 25, 26, 27, 28, 29, 30 Dielectric substrate 11a, 11b, 12, 13a, 13b, 14, 31
a, 31b, 32a, 32b, 33a, 33b, 34
a, 34b Conductor film for coil 17a, 17b, 17c, 17d, 37a, 37b, 3
7c, 37d, 37e, 37f, 37g, 37h Through-hole electrode

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01F 19/06 H01F 17/00

Claims (2)

(57) [Claims] 1. A dielectric material having a dielectric constant of 6 to 12.
A dielectric substrate, a conductor film formed on the dielectric substrate,
A dielectric substrate is laminated, and the conductive film is connected within the laminate.
To form at least four coils, and the four coils
Out of the two coils make up a transformer in pairs,
This is a laminated RF transformer having two transformers.
The dielectric between the conductor films constituting the transformer
The thickness of the body layer is 40 to 100 μm,
The thickness of the dielectric layer between the
1 dB insertion loss from 00 MHz to 2000 MHz
A multilayer RF transformer having the following characteristics . 2. One of a pair of coils in the transformer is formed only on one dielectric substrate, and the other coil is formed on upper and lower sides of the dielectric substrate forming the one coil. The multilayer RF transformer according to claim 1, wherein the multilayer RF transformer is configured by connecting conductive films formed on a single dielectric substrate.