JPH1098308A - Non-reversible circuit element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-reversible circuit element contributing to miniaturization and reduction in price by increasing an attenuation quantity outside the band, so as to sharply reduce the generation of useless radiation. SOLUTION: On one main surface (upper surface) of the terminal substrate of an isolator, two inductance electrodes Lf consisting of electrode patterns in the shape of a hair pin are provided, connecting electrodes 91a and 92a are formed at one terminal of each inductance electrode Lf, and an earth electrode 93 are formed. On the other main surface (lower surface), input/output electrodes 91 and 92 and an earth electrode 93 are formed. The other terminal side of each inductance electrode Lf and the input/output electrodes 91 and 92 are respectively connected by end-face electrodes, and the earth electrodes 93 formed on the upper and lower surfaces are connected by the end-face electrode and a through hole 96. The respective connection electrodes 91a and 92a are electrically connected to the tip part (port part) of a central conductor on the input/output side of the isolator.

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 high frequency band such as a microwave band, for example, an isolator and a circulator, and particularly to miniaturization and cost reduction when used in mobile communication equipment. The present invention relates to a non-reciprocal circuit device that can be used.

[0002]

2. Description of the Related Art Generally, non-reciprocal circuit devices such as lumped-constant isolators and circulators have characteristics in which attenuation is extremely small in a signal transmission direction and extremely large in a reverse direction. Conventionally, as this type of isolator, there is an isolator having a structure as shown in FIG.

This isolator is mainly composed of an upper yoke 2
And a lower yoke 8 in a magnetically closed circuit, three permanent conductors 51, 52, 53
Are disposed so as to cross each other, and a resin case 7 is provided, and input / output electrodes 91 and 9 are provided on the lower surface of the lower yoke.
2 and a terminal board 9 on which a ground electrode 93 is formed. The port portions P1 and P2 of the center conductors 51 and 52 are connected to input / output connection terminals 71 and 72 and matching capacitors Co and Co provided in the resin case 7, and the port portion P3 of the center conductor 53 is matched. Capacitor Co and the terminating resistor R, each capacitor Co
One end of the terminating resistor R is connected to ground terminals 73 and 73, and the input / output connection terminals 71 and 72 and the ground terminal 73 are connected to input / output electrodes 91 and 92 and a ground electrode 93 formed on the terminal board 9, respectively. I have.

The terminal board 9 is used to change the shape and position of the signal input / output section to increase the degree of freedom in designing the signal input / output section of the isolator and to obtain a stable and reliable connection with the mounting board. The input / output electrodes 91 and 92 and the ground electrode 93 are formed on both main surfaces of the terminal substrate 9, and the respective electrodes on both main surfaces are connected by end surface electrodes or through holes.

FIG. 13 is an equivalent circuit diagram of this isolator. As shown in FIG. 13, the conventional isolator has ports P1, P1 at the tip of center conductors 51, 52, 53.
A matching capacitor Co is connected to each of P2 and P3 as a matching circuit, and a terminating resistor R is connected to one port P3. Note that each inductance L is a ferrite 5
4 and an equivalent inductance formed by the center conductors 51, 52 and 53.

[0006] The isolator is a mobile phone,
Adopted in the transmission / reception circuit part of the antenna shared circuit of mobile communication equipment such as mobile phones, the input / output transmission line and the ground electrode are formed on the front surface, and the surface electrode is mounted on the mounting substrate where the ground electrode is formed on almost the entire back surface Being used.

[0007]

Generally, an amplifier incorporated in such a communication device has nonlinearity, which causes unnecessary radiation, that is, spurious (an integer multiple of the fundamental wave, particularly, a second harmonic). (3rd harmonic).
Since this unnecessary radiation causes interference and abnormal operation of the power amplification unit of another communication device, it is standardized that the unnecessary radiation be below a certain level.

Further, the isolator also has a band-pass filter function as a characteristic in the transmission direction, and thus has a characteristic that in a frequency band apart from the pass band, the attenuation is large even in the transmission direction. However, isolators are not originally designed to provide out-of-band attenuation,
With the above-described conventional isolator, it is not possible to obtain a desired attenuation in a frequency band of unnecessary radiation (particularly, a second harmonic and a third harmonic of a fundamental wave). For this reason, a conventional communication device of this type employs a method of attenuating unnecessary radiation by using a separate filter or the like.

That is, when the above-mentioned conventional isolator is used, a filter for preventing unnecessary radiation is necessary as described above, and there is a problem that the cost of parts is increased and the size is increased by the amount of the filter. However, there has been a problem that demands for lower prices cannot be met.

Accordingly, an object of the present invention is to provide a non-reciprocal circuit device which can greatly reduce the generation of unnecessary radiation by increasing the amount of attenuation outside the band, thereby contributing to miniaturization and cost reduction. To provide.

[0011]

In order to achieve the above object, the invention according to claim 1 is directed to a magnetic body to which a DC magnetic field is applied, and a plurality of central conductors arranged crossing the magnetic body. A non-reciprocal circuit device comprising: a matching capacitor connected between a port portion of each central conductor and ground; and a terminal substrate on which input / output electrodes and a ground electrode are formed. Wherein two inductances are formed, and the inductance is electrically connected between at least one of the port portions of the center conductor and the input / output electrode corresponding to the port portion. .

According to a second aspect of the present invention, in the non-reciprocal circuit device according to the first aspect, the inductance and the matching capacitor formed on the terminal substrate and the mounting board on which the non-reciprocal circuit device is mounted are mounted. A low-pass filter is formed by the electrode distribution capacitance of the output transmission line.

According to a third aspect of the present invention, in the non-reciprocal circuit device according to the first or second aspect, the inductance is formed in an electrode pattern on or inside the terminal substrate. Things.

According to a fourth aspect of the present invention, in the non-reciprocal circuit device according to the third aspect, a capacitor electrode that is electrically connected to the input / output electrode side of the inductance is formed on the terminal board, and the inductance of the inductance is reduced by the capacitor electrode. A capacitor is formed between the input / output electrode side and the ground.

According to the above configuration, a low-pass filter is formed by the formed inductance formed on the terminal board, the matching capacity, and the external capacity such as the electrode distribution capacity of the input / output transmission line of the mounting board. Therefore, the amount of attenuation outside the band can be significantly improved.

That is, the inductance and capacitance constituting the low-pass filter can be formed in the non-reciprocal circuit element without changing the external dimensions, and the inductance and capacitance and the electrode distribution capacitance and the like formed on the mounting board can be formed. Since a low-pass filter can be configured with the external capacitance of the present invention, if the nonreciprocal circuit device according to the present invention is used, unnecessary radiation can be reduced without using another filter for preventing unnecessary radiation which has been conventionally required. It can be significantly reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof.

FIGS. 1 to 4 show the structure and configuration of an isolator according to a first embodiment of the present invention. FIG. 1 is an exploded perspective view of the isolator, FIG. 2 is a plan view showing a state in which a permanent magnet, an upper yoke and a terminal board are removed, FIG. 3A is a plan view of an upper surface of the terminal board, and FIG. FIG. 4 is a plan view of the lower surface of the substrate, and FIG. 4 is an equivalent circuit diagram. The matching capacitors and inductance electrodes shown in FIGS. 1 and 2 correspond to the matching capacitance and inductance shown in FIG. 4, respectively, and are denoted by the same reference numerals.

As shown in FIGS. 1 to 3, the isolator of this embodiment has a permanent magnet 3 disposed on the inner surface of a box-shaped upper yoke 2 made of a magnetic metal, and the upper yoke 2 has the same magnetic material. A substantially closed U-shaped lower yoke 8 made of metal is mounted to form a magnetic closed circuit. A resin case 7 is disposed on a bottom surface 8a in the lower yoke 8, and a magnetic assembly is provided in the resin case 7. 5, a matching capacitor C1 to C3, a terminating resistor R are provided, a terminal board 9 is provided on the lower surface of the lower yoke 8, and a permanent magnet 3 applies a DC magnetic field to the magnetic assembly 5. Have been.

The magnetic assembly 5 includes a disk-shaped ferrite 54.
Three central conductors 51 to 51 made of a thin metal plate
In this structure, three center conductors 51 to 53 are bent at an angle of 120 degrees from each other on an upper surface of the ferrite 54 with an insulating sheet (not shown) interposed therebetween. Port portions P1 to P3 on the distal end side of the central conductors 51 to 53 are configured to protrude outward.

The resin case 7 is made of an electrically insulating member and has a structure in which a bottom wall 7b is integrally formed with a rectangular frame-shaped side wall 7a, and input / output connection terminals 71 and 72 and a ground terminal 73 are provided at predetermined locations. 73, an insertion hole 7c is formed at a substantially central portion of the bottom wall 7b, and matching capacitors C1 to C3 and a terminating resistor R are provided at predetermined positions on a peripheral portion of the insertion hole 7c.
Are formed in the recess. The input / output connection terminals 71, 72 and the ground terminals 73, 73 are embedded in resin at the center, and the other end is exposed to the upper surface of the bottom wall 7b, and the other end is the lower surface of the bottom wall 7b and the side wall 7a. It is provided so that it may be exposed on the outer surface.

The terminal board 9 is made of a printed board of glass epoxy, plastic, Teflon or the like, a resin plate of liquid crystal polymer or the like, or a ceramic board of alumina or the like. Figure 1
3A, two inductance electrodes Lf formed of a hairpin-shaped electrode pattern, connection electrodes 91a and 92a, and an earth electrode 93 are formed at one end of each inductance electrode Lf, and the other main surface (FIG. As shown in FIG. 3B, input / output electrodes 91,
92 and an earth electrode 93 are formed. The other end of each inductance electrode Lf and the input / output electrodes 91 and 92 are connected by end face electrodes 95, respectively.
Connected by

The recesses formed in the periphery of the insertion hole 7c of the resin case 7 have matching chip capacitors C1 to C3,
The chip terminating resistor R is arranged, and the magnetic assembly 5 is inserted and arranged in the insertion hole 7c. The ground portion of each of the center conductors 51 to 53 on the lower surface of the magnetic assembly 5 is connected to the bottom surface 8a of the lower yoke 8.
It is connected to the. The lower electrodes of the capacitors C1 to C3 and the electrode on one end of the terminating resistor R are connected to ground terminals 73 and 73, respectively.

The ports P1 to P3 of the center conductors 51 to 53 are connected to the upper electrodes of the capacitors C1 to C3, respectively, and the other end of the terminating resistor R is connected to the port P3. Port portion P of input / output side center electrodes 51 and 52
Reference numerals 1 and P2 are connected to portions of the input / output connection terminals 71 and 72 exposed on the upper surface of the bottom wall 7b.

The input / output connection terminals 7 of the resin case 7
1 and 72 are connected to the connection electrodes 91a and 92 of the terminal substrate 9 respectively.
a, and ground terminals 73, 73 are ground electrodes 93.
It is connected to the.

As described above, the center conductor 51 on the input / output side,
52 are connected to input / output connection terminals 7
1, 72 and an input / output electrode 91, 92 via an inductance electrode Lf formed on the terminal board 9. That is, in the isolator of the present embodiment, as shown in the equivalent circuit diagram of FIG. 4, matching capacitors C1 to C3 are connected to ports P1 to P3 corresponding to the tips of the center conductors 51, 52, and 53, and one port P3 is connected to one port P3. Is connected to a terminating resistor R,
An inductance Lf is connected between the two ports P1 and P2 and the input / output electrodes 91 and 92, respectively.

As shown in FIG. 5, this isolator is surface-mounted on a mounting substrate 10 having an input / output transmission line 1112 and a ground electrode 13 formed on the front surface and a ground electrode formed on substantially the entire back surface. used. Specifically, the input / output electrodes 91 and 92 of the isolator are connected to the transmission line 1.
The ground electrode 93 of the isolator is connected to the ground electrode 1 of the mounting board 10 on the soldering lands 11a and 12a
3 and 13 are mounted by soldering. The soldering lands 11a and 12a to which the input / output electrodes 91 and 92 of the isolator are soldered are formed wider than other portions in order to obtain sufficient mounting strength (soldering strength). Electrode distributed capacitances C are provided between the ground electrodes 11a and 12a and the ground electrodes formed on the back surface, respectively.
p occurs inevitably.

Next, the operation and effect of the isolator of this embodiment will be described. 6 and 7 are equivalent circuit diagrams in a state where the above-described isolator is mounted on the mounting board 10, and FIG. 7 is an equivalent circuit diagram for explaining an operation (operation principle) in a mounted state.

As shown in FIG. 6, when the isolator of this embodiment is mounted on the mounting board 10 (see FIG. 5),
Electrode distribution capacitances Cp, C generated parasitically on the soldering lands 11a, 12a of the transmission lines 11, 12 of the mounting substrate 10.
p is connected to the input / output electrodes 91 and 92 of the isolator. Then, as shown in FIG. 7, an inductance Lf, a capacitance Cf which is a part of the matching capacitances C1 and C2, and a signal input / output unit (ports P1 and P2 side) of the isolator.
Further, a π-type low-pass filter LPF composed of the electrode distribution capacitance Cp of the mounting substrate 10 as an external capacitance is formed.

That is, the matching capacitors C1 and C2 of the isolator of the present embodiment are configured by a parallel capacitance of a capacitor Co functioning as a matching circuit of the isolator and a capacitor Cf forming the π-type low-pass filter LPF. I have. That is, the matching capacitors C1 and C2 of the isolator of the present embodiment are:
It is set to a value obtained by adding the capacitance Cf to the matching capacitance Co of the conventional isolator. For example, in the 1.5 GHz band, the capacity Co is set to about 5 pF, the capacity Cf is set to about 2 pF, and in the 900 MHz band, the capacity Co is set to about 10 pF.
F, the capacitance Cf is set to about 3 pF, and the inductance L
f is set to about 2 nH to 3 nH.

The capacitance Cf is usually set so that the input / output impedance of the isolator (normally, 50Ω) does not change.
It is set to have the same value as the capacitance value of the electrode distribution capacitance Cp, but it is also possible to change the input / output impedance of the isolator by setting the inductance Lf, capacitance Cf, and electrode distribution capacitance Cp to appropriate values. It is.

The shape of the inductance Lf is not limited to the hairpin shape, but may be a loop shape. The inductance Lf is determined by the width of the electrode pattern of the inductance electrode Lf.
By changing the shape or the like, a desired value is set.

The values of the capacitance Cf, the electrode distribution capacitance Cp, and the inductance Lf are appropriately set in consideration of the thickness of the mounting board, the frequency band used, the electrical characteristics, the mounting strength, and the like.

FIG. 8 is a diagram showing frequency characteristics when the isolator of the present embodiment and the conventional isolator are mounted on a mounting board. The solid line indicates the characteristics according to the present embodiment, and the broken line indicates the conventional characteristics. . As shown in FIG. 8, it can be seen that the use of the isolator of the present embodiment greatly increases the attenuation on the high frequency band side as compared with the conventional one.

As described above, in the isolator of the present embodiment, the inductances Lf and Lf are formed on the terminal board 9, and when mounted on the mounting board 10, the inductance Lf is applied to each signal input / output section. And matching capacitance C1
(Or C2) and the electrode distribution capacitance Cp of the mounting substrate 10 form a low-pass filter LPF, and as shown in FIG. 8, the attenuation outside the band is significantly improved as compared with the conventional one. Becomes

That is, the isolator of this embodiment includes:
The inductance Lf and the capacitance Cf constituting the low-pass filter LPF are built in without changing the external dimensions, and the mounting substrate 10 has solder lands 11 a and 12
a represents the electrode distribution capacitance C constituting the low-pass filter LPF
p is inevitably formed, and if the isolator of this embodiment is used, unnecessary radiation can be greatly reduced without using another filter for preventing unnecessary radiation, which was conventionally required. Can be reduced in size and cost.

Next, the structure of a terminal board according to a second embodiment of the present invention is shown in FIGS. FIG. 9 is a perspective view of a terminal board having a multilayer structure, FIG. 10A is an upper surface of the first layer of the terminal board 9 shown in FIG. 9, FIG.
(C) is a plan view of the lower surface of the third layer.

The terminal board 9 of this embodiment is a printed circuit board 9
a, 9b, 9c is a multi-layer substrate of a three-layer structure in which
As shown in FIGS. 9 and 10A, connection electrodes 91a and 92a and a ground electrode 93 are formed on the upper surface of the first layer substrate 9a, and a substantially U-shaped inductance electrode Lf is formed on the lower surface of the first layer substrate 9a. , Lf, and input / output electrodes 91 and 92 and a ground electrode 93 are formed on the lower surface of the third-layer substrate 9c. One end of each inductance electrode Lf is connected to a connection electrode 91a, 92a by a through hole 96, and the other end is an input / output electrode 91, 92 by an end face electrode 95.
, And each ground electrode 93 is connected by an end face electrode 95 and a through hole 96. The second-layer substrate 9b is for joining the first-layer substrate 9a and the third-layer substrate 9c, and has no electrodes formed on any of the upper and lower surfaces.

That is, the inductance electrode Lf formed on the terminal board 9 of this embodiment is formed inside the multilayer board 9. As described above, when the inductance electrode Lf is formed inside the terminal board 9, the inductance electrode Lf
Can have more various shapes, and the degree of freedom in designing the inductance value can be increased.

Next, FIG. 11 shows the configuration of a terminal board according to a third embodiment of the present invention. The terminal board 9 of this embodiment is a multi-layer board having a three-layer structure as in the case of the second embodiment.
11B shows the upper surface of the first layer, FIG. 11B shows the lower surface of the first layer, and FIG.
FIG. 11C is a plan view of the upper surface of the third layer, and FIG. 11D is a plan view of the lower surface of the third layer.

As shown in FIG. 11B, on the lower surface of the first layer substrate 9a of the terminal substrate 9 of the present embodiment, the respective inductance electrodes Lf are connected to the connection side of the input / output electrodes 91 and 92. A capacitor electrode Cd is formed. A capacitance is formed between the capacitor electrode Cd and the upper surface of the first-layer substrate 9a and the ground electrode 93 on the upper surface of the third-layer substrate. This capacitance is a part of the capacitance on the input / output electrode side of the π-type low-pass filter LPF, and is connected in parallel with the above-mentioned electrode distribution capacitance Cp of the mounting board while mounted on the mounting board. Is done.

When the terminal board 9 of this embodiment is used, one capacity of the π-type low-pass filter LPF is formed by the parallel capacity of the electrode distribution capacity Cp of the mounting board and the capacity of the capacitor electrode Cd. The area of the soldering land on the substrate can be reduced.

That is, by using the isolator of this embodiment, the degree of freedom in setting the capacitance value of the π-type low-pass filter LPF can be increased, so that a more suitable low-pass filter LPF can be constructed. Further, it is possible to make the soldering land of the mounting board an optimal shape (area).

In the above-described embodiment, the description has been given of the case where the electrode distributed capacitance formed on the soldering land portion of the mounting board is used as the external capacitance. However, the external capacitance is not limited to this. A capacitor or the like may be used.

In the above embodiment, the case where two inductance electrodes Lf are formed on the terminal board 9 has been described. However, the present invention is not limited to this, and the inductance electrode Lf is formed only on one of the signal input / output sides. The configuration may be as follows.

In the above embodiment, an isolator has been described as an example. However, the present invention is also applicable to a circulator in which the port P3 is configured as a third input / output unit without connecting the terminating resistor R to the port P3. Can be.

The overall structure is not limited to those shown in FIGS. 1 and 2 of the above embodiment. The present invention is applied to a non-reciprocal circuit device using a terminal board, and other configurations are not particularly limited.

[0048]

As described above, according to the non-reciprocal circuit device according to the present invention, the inductance is formed on the terminal board, the inductance formed on the terminal board, the matching capacitance, and the input / output of the mounting board. Since a low-pass filter can be formed with the external capacitance such as the electrode distribution capacitance of the transmission line, the amount of attenuation outside the band can be significantly improved.

That is, the inductance and capacitance constituting the low-pass filter can be formed in the non-reciprocal circuit element without changing the external dimensions. The inductance and capacitance and the electrode distribution capacitance and the like formed on the mounting board can be formed. And the external capacitance can form a low-pass filter. Therefore, if the non-reciprocal circuit device according to the present invention is used, another filter for preventing unnecessary radiation can be made unnecessary, and downsizing and cost reduction of communication equipment and the like can be achieved.

[Brief description of the drawings]

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

FIG. 2 is a plan view of the isolator according to the first embodiment of the present invention.

FIG. 3A is a plan view of an upper surface of a terminal substrate according to the first embodiment of the present invention, and FIG. 3B is a plan view of a lower surface of the terminal substrate.

FIG. 4 is an equivalent circuit diagram of the isolator according to the present invention.

FIG. 5 is a perspective view showing a mounted state of the isolator according to the present invention.

FIG. 6 is an equivalent circuit diagram in a mounted state of the isolator according to the present invention.

FIG. 7 is an equivalent circuit diagram for explaining an operation of the isolator according to the present invention in a mounted state.

FIG. 8 is a frequency characteristic diagram of the present invention and a conventional isolator.

FIG. 9 is a perspective view of a terminal board according to a second embodiment of the present invention.

10A is a plan view of an upper surface of a first-layer substrate of a terminal substrate according to a second embodiment of the present invention, FIG. 10B is a plan view of a lower surface of the first-layer substrate, and FIG. It is a top view of the eye substrate lower surface.

11A is a plan view of a top surface of a first-layer substrate according to a third embodiment of the present invention, FIG. 11B is a plan view of a bottom surface of the first-layer substrate, and FIG. Top view, (d) is 3
It is a top view of the lower surface of a layer substrate.

FIG. 12 is an exploded perspective view of a conventional isolator.

FIG. 13 is an equivalent circuit diagram of a conventional isolator.

[Explanation of symbols]

2 Upper Yoke 3 Permanent Magnet 5 Magnetic Assembly 51-53 Center Conductor 54 Ferrite 7 Resin Case 71, 72 Input / Output Connection Terminal 73 Ground Terminal 8 Lower Yoke 9 Terminal Board 91, 92 Input / Output Electrodes 91a, 92a Connection Electrode 10 Mounting Board 11, 12 Transmission line 11a, 12a Soldering land C1 to C3 Matching capacitance (capacitor) R Termination resistance Lf Inductance (inductance electrode) Cd Capacitor electrode Cp Electrode distribution capacitance P1 to P3 Port (port part)

Claims (4)

[Claims] 1. A magnetic body to which a DC magnetic field is applied, a plurality of center conductors arranged to cross each other on the magnetic body, a matching capacitor connected between a port of each center conductor and ground, What is claimed is: 1. A non-reciprocal circuit device comprising: a terminal substrate on which an output electrode and a ground electrode are formed, wherein at least one inductance is formed on the terminal substrate, and the inductance is at least one of ports of a center conductor port A non-reciprocal circuit device electrically connected between the unit and an input / output electrode corresponding to the port unit. 2. A low-pass filter is formed by the inductance formed on the terminal substrate, the matching capacitance, and an electrode distribution capacitance of an input / output transmission line of a mounting substrate on which the non-reciprocal circuit device is mounted. The non-reciprocal circuit device according to claim 1, wherein: 3. The non-reciprocal circuit device according to claim 1, wherein the inductance is formed in an electrode pattern on a surface or inside of the terminal substrate. 4. A method according to claim 1, wherein a capacitor electrode is formed on said terminal board, said capacitor electrode being electrically connected to said input / output electrode side of said inductance, and said capacitor electrode forms a capacitance between said input / output electrode side of said inductance and ground. The non-reciprocal circuit device according to claim 3, wherein: