JP2002185216A - Non-reciprocal circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an isolator which is high in directional properties even if signals inputted into a coupling terminal are reduced in intensity. SOLUTION: A non-reciprocal circuit device is composed of a center conductor assembly 2 consisting of a ferrimagnetic material 20 and center conductors 21, 22, and 23 which are provided so as to cross the ferromagnetic material 20 as being electrically insulated from each other, a laminated element (capacitor board) 1 where an input/output capacitor connected to the input/output terminals of the center conductors and a load capacitor are formed into electrode patterns on a plurality of green sheets, a permanent magnet 4 which applies a direct current magnetic field to the center conductor assembly 2, and metal cases 5 and 6 which serve also as magnetic yokes and house the above component parts. An input capacity electrode 51, an output capacity electrode 52, the load electrode 53, and an output detection capacity electrode 61 are formed on the same plane of the same green sheet, at least the resistor connection pattern of the load electrode and preferably a ground electrode are not arranged on the upper and lower projection planes of the output detection capacity electrodes 61 and 62, so that a non-reciprocal circuit device with a coupler function restraining a parasitic capacity from occurring can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-reciprocal circuit device used in a transmission / reception apparatus in which at least one antenna is shared between a transmission system and a reception system, such as a portable telephone, and more particularly, to a function of detecting an output of an amplifier. The present invention relates to a non-reciprocal circuit device provided (hereinafter referred to as an isolator with a coupling terminal or simply an isolator).

[0002]

2. Description of the Related Art In general, a transmission / reception device of a mobile communication device used for a portable telephone, a car telephone, or the like is configured so that an antenna is shared by a branch portion of one antenna for a transmission system and a reception system. . In the transmission system of this transmission / reception device, it is necessary to keep the output power of an amplifier (amplifier) constant. Further, it is necessary to prevent the amplifier from being damaged by the reflected power from the antenna or the like, or to prevent IM (intermodulation) from occurring due to a signal of an adjacent channel entering from the antenna. Therefore, the output power from the amplifier is detected by a directional coupler (coupler) and the output power of the amplifier is controlled by an APC circuit, and an isolator is provided on the subsequent stage of the directional coupler. To prevent the amplifier from being damaged by the reflected wave and the occurrence of IM.

However, the use of the directional coupler increases the number of components and the mounting area on the circuit board, and cannot meet the demand for miniaturization and cost reduction. Therefore, according to Japanese Patent Application Laid-Open No. 9-270608, etc., a capacitor is connected by branching from the input terminal of the isolator, and this capacitor is connected in parallel to the transmission line of the APC circuit to form an output detection capacitor. It has been proposed to monitor the output of the amplifier with a ring terminal. It also discloses that the capacitor is printed and formed on a thin sheet as an electrode pattern, and these are laminated and integrally formed to reduce the size.

[0004]

Therefore, the inventors of the present invention based on the equivalent circuit diagram shown in FIG.
An isolator with a coupling terminal in which No. 4 was connected in parallel with the input terminal (IN) was prototyped. FIG. 4 is a development view of a green sheet of a laminated element body (capacitance element substrate) constituting a capacitance section. Here, the laminated element bodies are laminated in the order of (a) to (e) from above, and (e) ′ indicates the back surface of (e). (A)
Electrodes for matching capacitors are formed on the layers by pattern printing, and land patterns 14 and 15 for resistance connection with the input capacitor electrode 11, the output capacitor electrode 12, and the load capacitor electrode 13, respectively, are formed, (b) In the layer, ground electrodes 41 and 42 are formed, and in the (c) layer, an input capacitance electrode 51, an output capacitance electrode 52 and a load capacitance electrode 53 which form a capacitance together with the input / output electrodes and the like are formed. The electrode 61 constituting the detection capacitor C4 is provided at the illustrated position on the same plane. Next, in the layer (d), one capacitance electrode 62 forming C4 together with the ground electrodes 43 and 44 and the capacitance electrode 61 is formed. The (e) layer is provided with a through hole for connecting an upper input / output electrode, an output detection capacitor electrode, and each ground electrode to each electrode formed on the back surface, and a ground (earth) electrode 45 and an input / output Electrodes 46 and 47 to be connected to external terminal electrodes
And a coupling terminal electrode 48 and the like.
These green sheets were sequentially laminated from the bottom, thermocompressed, and then fired to obtain a sintered body. After assembling an isolator using this laminated body, the electrical characteristics of the following items were measured. Table 1 shows the results.

[0005]

[Table 1]

What should be noted here is the directionality (dB). Directivity is also called directivity and indicates the accuracy of the coupler function. This is the ratio of the signal strength (coupling) at which the signal input from the input terminal is output from the coupling terminal to the signal strength (isolation 2) at which the signal input from the output terminal is output from the coupling terminal, that is, This is a value obtained by subtracting the coupling value (dB) from the value of isolation 2 (dB). The larger the value, the more the coupling terminal takes out only the input signal, and it can be said that the accuracy as the coupler is high. At present, it is considered that this value should be 10 (dB) or more, but the coupler function needs to be highly directional in order to control the amplifier with higher precision as the amplifier becomes more efficient and lower power consumption. ing. In view of the above, the present invention has been made in view of the above-described problem of directivity in the prototypes of the present inventors, and has as its object to provide an isolator having a coupler function with high directivity.

[0007]

According to the present invention, there is provided a center conductor assembly comprising a plurality of center conductors provided on a ferrimagnetic material so as to cross each other in an electrically insulated state, and an input / output end of the center conductor. A laminated element body in which an input / output capacitor and a load capacitor connected to each other are formed on a plurality of green sheets with an electrode pattern, a terminating resistor and a permanent magnet for applying a DC magnetic field to the center conductor assembly. In a non-reciprocal circuit element having an input terminal, an output terminal, a ground terminal, and a terminal for output detection provided in a metal case also serving as a magnetic yoke, This is a non-reciprocal circuit element in which a conductor provided (constituting the path) in a path through which a microwave incident from an output terminal is transmitted is not disposed on the upper and lower projection surfaces of the capacitor electrode.

That is, the microwave incident from the output terminal is transmitted to the output capacitance electrode formed on the surface and inside of the multilayer body, and transmitted to the garnet through the center conductor having one end connected to the output capacitance electrode. By the action of a constant static magnetic field applied to the garnet, the microwave is bent by 120 ° and transmitted at one end to the center electrode connected to the load capacitance electrode, and the load formed on the surface and inside of the multilayer body To the storage capacitor electrode. Furthermore, it is terminated to ground through a resistor via a resistor connection electrode connected to this electrode. This is a non-reciprocal circuit device in which electrodes and resistors in this series of paths are not arranged. Specifically, an output capacitance electrode, an electrode electrically connected thereto,
There is a load capacitance electrode, a resistance connection electrode electrically connected to the load capacitance electrode, and a resistor, and at least one of them is not arranged. Here, in particular, the target is often a resistance connection electrode pattern electrically connected to the load capacitance electrode and a resistance. Further, in the non-reciprocal circuit device, a ground electrode is not arranged on the upper and lower projection surfaces of the output detection capacitance electrode.
It is desirable to form a resistor with a thick film on the surface or inside of the multilayer body. Further, the central conductor can also be a non-reciprocal circuit device composed of a laminated body formed of an electrode pattern on a plurality of green sheets.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention considers the directivity (directivity) by giving a uniform arrangement in consideration of the interference between the output detecting capacitor electrode and various electrodes from the output terminal to the coupling terminal in the laminated body. ). That is, in principle, various electrodes are not arranged on the surface on which the output detection capacitance electrode formed in the multilayer body is projected up and down. For example, a resistor connection electrode pattern, and thus a resistor is not arranged. With such a configuration, it is suppressed that a reflected signal from the output side leaks to the coupling terminal, which is a considerable amount in the related art, and the directionality is improved. Conversely, no consideration has been given to the conventional arrangement of the output detection capacitor electrode, the load capacitor electrode, and the terminating resistor. It can be said that the cause is that a capacitance is generated and a reflected signal that is not completely removed in the load section leaks to the coupling terminal side. In addition, when the ground electrode is arranged near the output detection capacitance electrode, it has been recognized that another parasitic capacitance is formed between the output terminal and the coupling terminal. Therefore, the ground electrode should not be provided on the upper and lower projection surfaces. I made it. As described above, the present invention is characterized in that the positions of the output detection capacitance electrode and the electrode forming the parasitic capacitance are improved. Therefore, the directionality after the improvement can obtain a value of 15 dB or more.

An embodiment of the isolator with a coupling terminal according to the present invention will be described below with reference to the drawings. FIG. 1 is a development view of a laminated element body (capacitance element substrate). FIG. 2 is an equivalent circuit diagram of the isolator with the coupling terminal. FIG. 3 is an exploded perspective view showing an example of this isolator.
First, an isolator with a coupling terminal will be described with reference to FIGS. The basic configuration of the isolator of the present example is a center conductor in which center conductors 21, 22, and 23 made of three strip lines are woven at intervals of 120 degrees through a ferrimagnetic material (ferrite garnet) 20 such as garnet via an insulator. The assembly 2 and the center conductor assembly 2
Element body 1 in which can be accommodated in central through hole 16
And a permanent magnet 4 such as a ferrite magnet for applying a DC magnetic field to the center conductor assembly 2, a lower case 6 like the metal upper case 5 also serving as a magnetic yoke, and the The conductive plate 30 such as a Cu plate is
And a resin base 3 integrally incorporated therein. One end of each central conductor is soldered to the upper surface of the conductive plate 30 of the resin base 3, and the lower surface of the conductive plate fits into the central metal part of the lower case 6. External electrodes 32 and 33 serving as input / output terminals and external electrodes 40 serving as coupling terminals are provided on the resin frames 31 at the left and right ends of the resin base 3.
In addition, the external electrode 34 of the load terminal and another ground electrode are formed facing the mounting substrate surface so as to be surface mountable.

Next, in FIG. 2, terminals P1, P2, P
C1, C2, C connected between 3 and ground (earth)
Reference numeral 3 denotes a matching capacitor which determines the operating frequency of the circulator, and which is connected in parallel to the center conductor 2 of the center conductor assembly 2.
1, 22, and 23 are connected to each other to add an inductance L component. In order to form an isolator, a terminating resistor R1 is connected in parallel to a capacitor C3 and dropped to the ground. This resistor R1 is formed by providing a printed resistor 7, a chip resistor, and the like on the upper surface of a capacitive element substrate. . The input terminal (IN), the output terminal (OUT), and the load terminal (Load) correspond to the external electrodes 32, 33, and 34 of the resin base 3, and the matching capacitors C1, C2, and C3 are printed and formed on the capacitor substrate. Electrodes 1 each forming a capacitor
1, 12, and 13. A capacitance C4 connected in parallel between the input terminal 32 (IN) and the coupling terminal 40 (Coupling) is an output detection capacitance of the amplifier, and is a part of the output signal of the amplifier that enters the isolator from the input terminal. Is determined so that the amount of the output from the coupling terminal, that is, the coupling amount, becomes a predetermined value. The capacitor C4 is formed in the multilayer body 1 in an electrode pattern as described below. Note that the center conductor assembly 2 can be composed of a laminate made of a dielectric material or a magnetic material, whereby the number of assembling steps can be reduced and the cost can be further reduced. In addition, the entire center conductor assembly 2 can be formed by laminating a plurality of green sheets of a magnetic material, whereby the thickness of the center conductor assembly can be further reduced.

The laminated body (capacitive element substrate) 1 of this embodiment
Is made of a ceramic dielectric material that can be fired at a low temperature of about 900 ° C., and has a relative permittivity εr of about 8 and a thickness of 30 to
A desired electrode pattern is formed by creating a green sheet of about 100 μm by a doctor blade method and printing a conductive paste mainly composed of Ag on the green sheet. These dielectric green sheets are laminated and thermocompression-bonded to form a through hole 16 in the center, and then sintered to form an integrated laminated sintered body.
The laminated body 1 and the center conductor assembly 2 are manufactured separately, and after the center conductor assembly 2 is fitted and mounted in the through hole 16 of the laminated body 1, each of the center conductors 21, 22, 23 is formed. One end is soldered to the conductive plate 30, and the other end is electrically connected to the electrodes 11, 12, 13 on the upper surface of the multilayer body 1 by soldering. Next, the upper case to which the permanent magnet 4 is attached and the lower case 6 to which the resin base 3 is attached are assembled to form an isolator.

Next, the internal structure of the laminated body 1 will be described with reference to a developed view of a green sheet shown in FIG. The laminated body 1 of the embodiment includes (a1), (b1), (c1), (d1), and (e1).
1) A multilayer structure composed of dielectric green sheets, wherein layers (b1) to (e1) except for (a1) are basically the same as the laminates (b) to (e) described in FIG. And an electrode pattern. Therefore, the laminated body is (a
The layers are stacked in the order of 1) to (e1), and (e1 ′) at the bottom indicates the back surface of (e1). (B1) layer ground electrodes 41 and 42, (c1) layer input capacitance electrode 51, output capacitance electrode 52, load capacitance electrode 53 and output detection capacitance electrode 61, (d1) layer ground electrodes 43 and 44 and the other. One of the output detection capacitor electrode 62, the ground electrode 45 of (e1 '), the external input / output electrodes 46 and 47, the coupling electrode 48, and the like are denoted by the same reference numerals as in FIG. However, these configurations do not necessarily have to be the same, and the number of sheets and the arrangement shape of the electrode patterns can be changed. Further, in the present example, the connection between the electrode patterns is all made through the internal through holes, but it is a matter of course that the connection may be made up of the external electrodes on the side surfaces.

Now, regarding the (a1) layer, the input capacitance electrode 11 and the output capacitance electrode 12 are formed in the same position and shape as in FIG. 4 (a). However, the load capacitance electrode 131 and the resistance connection patterns 141 and 151 are formed so as to be changed in shape to the lower right position shown in the drawing, excluding the region of S1 located on the projection plane of the output detection capacitance electrode. . That is, it can be said that this position is a position that is not on the upper and lower projection planes of the output detection capacitance electrodes 61 and 62 and is an arrangement that does not cause interference. The resistor can be used by connecting a chip resistor to the resistor connection pattern. However, if a thick film resistor is formed by printing or baking, it is preferable because it is more suitable for downsizing and the number of assembly steps can be reduced. This resistor is also formed at a position off the upper and lower projection planes of the output detection capacitance electrode. Although it is desirable to form each electrode pattern of the (c1) layer in a region sandwiched between the ground electrodes in order to improve the isolation, the electrode pattern which is the projection surface of the output detection capacitor electrode is formed.
It is desirable not to dispose a ground electrode in the area 2. By not arranging the electrode pattern related to the ground (earth) electrode in the vicinity of the upper and lower sides of the output detection capacitance electrode, generation of unnecessary parasitic capacitance is suppressed, and leakage of a reflected signal to the coupling terminal is prevented. Is improved, and the value of the isolation 2 can be made larger. Therefore, even if the coupling value is increased, the value of the isolation 2 is greatly improved, and the directional value is relatively improved. Next, Table 2 shows the results obtained by measuring the electrical characteristics of this example under the same conditions as those of the above-mentioned prototype.

[0015]

[Table 2]

As described above, the directionality was 18.4 dB, which was an increase of 65.8% as compared with the prototype (comparative example). The difference between the embodiment (FIG. 1) and the comparative example (FIG. 4) is that the resistance connection pattern electrically connected to the load electrode is on the projection surface of the output detection capacitance electrode. Met. Therefore, it is recognized that the positional relationship between the output detection capacitor electrode and the load electrode such as the resistor connection pattern affects the directionality. It should be noted that other output capacitance electrodes, electrodes electrically connected to the output capacitance electrodes, load capacitance electrodes, and the like may be arranged at the position S1, but from the viewpoint of the present invention, these electrode patterns are also subjected to output detection. It is desirable not to provide it on the projection surface of the storage capacitor electrode, thereby improving the directionality.

When there is a ground electrode on the projection surface of the output detection capacitor electrode, that is, when the ground electrode 41 of the (b1) layer shown in FIG. 1 is extended to the lower left of the drawing, between the output detection capacitor electrode and the ground electrode. When the generated parasitic capacitance was examined, it was 0.3 pF, but it was 0 in FIG.
Therefore, it was confirmed that it is preferable that the ground electrode is not provided on the projection surface of the output detection capacitor electrode because no parasitic capacitance occurs.

[0018]

As described above, in an isolator having a built-in coupler function in which an output detection capacitor electrode is formed by an electrode pattern in a laminated body, a resistor connection is provided in the vicinity of the output detection capacitor electrode on the upper and lower projection planes. The electrode pattern, the output capacitance electrode, the electrode electrically connected thereto, the load capacitance electrode, the resistor, and the ground electrode were not arranged. As a result, the reflection signal is prevented from leaking to the coupling terminal, and the directivity is improved.

[Brief description of the drawings]

FIG. 1 is a development view of a green sheet of a laminated body showing one embodiment of the non-reciprocal circuit device of the present invention.

FIG. 2 is an equivalent circuit diagram of a non-reciprocal circuit device having a coupling function.

FIG. 3 is an exploded perspective view showing an example of the structure of the non-reciprocal circuit device.

FIG. 4 is a development view of a green sheet showing an example of a laminated body provided with a coupling detection capacitor.

[Explanation of symbols]

1 ... laminated body (capacitance element substrate), 2 ... central conductor assembly,
3 resin base, 4 permanent magnet, 5 upper case (magnetic yoke), 6 lower case (magnetic yoke), 7 print resistance or chip resistance, 11, 51 input capacitance electrode, 12, 5
2: Capacitance electrode for output, 13, 53 ... Capacitance electrode for load,
14, 15: electrode for resistance connection, 16: through hole, 20: ferrimagnetic material, 21, 22, 23: central conductor, 30: conductive plate, 41, 42, 43, 44, 45: ground electrode, 4
6 input external electrodes, 47 output external electrodes, 48 coupling external electrodes, 61, 62 output detection capacitance electrodes, C
1, C2, C3: matching capacity, C4: output detecting capacity,
R1 ... Terminal resistance, (a), (b), (c), (d),
(E): Ceramic green sheet (a1), (b1), (c1), (d1), (e1): Ceramic green sheet

Claims (4)

[Claims] 1. A center conductor assembly comprising a plurality of center conductors provided on a ferrimagnetic material so as to cross each other in an electrically insulated state, an input / output capacitor and a load to which input / output terminals of the center conductor are connected. And a laminated element body formed with an electrode pattern on a plurality of green sheets, and a permanent magnet for applying a DC magnetic field to the terminating resistor and the center conductor assembly,
These are housed in a metal case also serving as a magnetic yoke, and in a non-reciprocal circuit device having an input terminal, an output terminal, a ground terminal, and a coupling terminal, a vertical projection of an output detection capacitor electrode provided in the laminated body. On the surface,
A non-reciprocal circuit device, wherein an electric conductor provided in a path through which a microwave incident from an output terminal is transmitted is not arranged. 2. An output capacitor electrode as the conductor,
A non-reciprocal circuit characterized by having an electrode electrically connected thereto, a load capacitance electrode, a resistance connection electrode electrically connected thereto, and a resistor, at least one of which is not disposed; element. 3. The non-reciprocal circuit device according to claim 1, wherein a resistor is formed by a thick film on the surface or inside of the multilayer body. 4. The non-reciprocal circuit device according to claim 1, wherein a ground electrode is not arranged on the upper and lower projection planes of the output detection capacitance electrode.