JP2001185912A - Non-reciprocal circuit element and communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-reciprocal circuit element which exhibits non- reciprocal characteristics over a wide band and has low insertion loss and a communication device which uses it. SOLUTION: A substrate 14 is provided with a 1st center electrode 4a and a 2nd center electrode 4b and the substrate 14 is provided between a ferrite plate 5 and a magnet 6; and solder resist film is formed on the surface of the substrate 14 to isolate the magnet 6 and center electrodes from each other. Consequently, conductor loss caused by a high-frequency current flowing to the magnet 6 is suppressed to reduce the insertion loss of the non-reciprocal circuit element.

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 such as an isolator or a gyrator used in a microwave band or the like, and a communication device using the same.

[0002]

2. Description of the Related Art A non-reciprocal circuit device used in a microwave band or the like is disclosed in US Pat.
-134349, JP-A-58-3402, JP-A-9-232818 and JP-A-8-8612.

The above nonreciprocal circuit element is an element in which a center electrode intersecting at a predetermined angle is provided on a ferrite plate to apply a static magnetic field to the ferrite plate. By rotating the plane of polarization of the high-frequency magnetic field generated by the principle of Faraday rotation, irreversible characteristics are generated.

[0004]

In the above-mentioned non-reciprocal circuit device using the first to third center electrodes,
Since the matching impedance of the third center electrode has a reactance component and the impedance depends on the frequency, the frequency range in which good irreversible characteristics are obtained is narrowed. In other words, the isolation characteristics when used as an isolator necessarily have a narrow band.

The inventors of the present invention have conducted intensive studies and experiments to obtain a non-reciprocal circuit device exhibiting good non-reciprocal characteristics over a wide band. In the process, they found the cause of the degradation of insertion loss over a wide band. That is, in the conventional non-reciprocal circuit device, a high-frequency current flows through a permanent magnet (hereinafter, simply referred to as a magnet), and power is consumed by the electric resistance of the magnet, which causes an increase in insertion loss. Was.

An object of the present invention is to provide a non-reciprocal circuit device exhibiting irreversible characteristics over a wide band and having a low insertion loss, and a communication device using the same.

[0007]

According to the present invention, one end is connected to an input terminal and the other end is grounded in order to suppress power consumption caused by a high-frequency magnetic field generated by a center electrode passing through a magnet and flowing a high-frequency current through the magnet. A first center electrode, which intersects the first center electrode in an insulated state, has one end connected to the output terminal, and has the other end grounded; A ferrimagnetic material close to the center electrode;
A magnet that applies a static magnetic field substantially perpendicular to the ferrimagnetic material, a first capacitor having one end connected to the input terminal, the other end grounded, and one end connected to the output terminal,
A non-reciprocal circuit device including a second capacitor having the other end grounded is provided, and an insulating spacer is provided between the magnet and the first or second center electrode.

[0008] With this structure, the close contact between the center electrode and the magnet is avoided, the coupling between the high-frequency magnetic field and the magnet by the first or second center electrode is weakened, and the conductor loss due to the high-frequency current induced in the magnet is also reduced. You.

Further, according to the present invention, the first and second center electrodes are constituted by conductor patterns provided on both surfaces of the substrate, and a resist film is provided on the surface, so that the resist film is used as the insulating spacer. .

Further, according to the present invention, a resistor connected between the input terminal and the output terminal is mounted on a substrate provided with the center electrode. This structure simplifies the mounting structure of the resistor and facilitates the configuration of the isolator.

Further, the present invention provides the above-mentioned conductor pattern,
It is made of a metal foil having a thickness of 30 μm or more, and the thickness of the resist film is set to 50 μm or more. Thereby, conductor loss due to the center electrode itself is suppressed, and conductor loss due to the magnet is also efficiently suppressed.

Further, according to the present invention, by attaching an insulating film to the magnet, the insulating film is used as an insulating spacer between the magnet and the center electrode.

Further, according to the present invention, the intersection angle between the first and second center conductors is set to a predetermined angle within a range of 90 degrees to 100 degrees. Thereby, a desired isolation characteristic is obtained.

Further, in the nonreciprocal circuit device according to the present invention, the ferrimagnetic material is formed in a substantially rectangular parallelepiped shape. Thereby, the center electrode is arranged in the diagonal direction of the ferrimagnetic material, the long center electrode is efficiently arranged, and low loss characteristics are obtained even if the ferrimagnetic material is small.

Further, according to the present invention, the capacitance values of the first and second capacitors are made substantially equal. Thereby, even if there is a difference between the inductances of the first and second center electrodes, the phase of the forward transmission signal from the input terminal to the output terminal and the phase of the reverse transmission signal from the output terminal to the input terminal are different from each other. The difference of approximately 18
By setting it to 0 °, desired isolation characteristics are obtained.

Further, according to the present invention, the first and second center electrodes, the ferrimagnetic material, the magnet, and the first and second capacitors are shielded and a magnetic field for applying the static magnetic field is provided. The circuit is surrounded by a yoke, and the yoke is set to the ground potential. With this structure,
The second center electrode and the capacitor are shielded together with the yoke at the ground potential.

Further, according to the present invention, an insulator layer is provided between the yoke and the center electrode. As a result, the yoke is separated from the center electrode to suppress high-frequency current generated in the yoke,
Q is increased and insertion loss is reduced.

The present invention also provides a plurality of ground terminals, at least two ground terminals and the input terminal are provided on one side of the case, and the other at least two ground terminals and the output terminal are connected to each other. Provided on the other side of the case. As a result, the ground connection is strengthened, unnecessary inductance and capacitance components are suppressed, direct waves are reduced, and the bandwidth (bandwidth showing low insertion loss characteristics) is widened.

Further, according to the present invention, a communication apparatus is constituted by using any one of the above non-reciprocal circuit elements and providing the non-reciprocal circuit element at an output section of an oscillation circuit or an input section of a filter.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an isolator according to a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is an exploded perspective view of the isolator. Here, reference numeral 1 denotes a resin case in which the input / output terminal and the ground terminal 3 are insert-molded. Reference numeral 2a denotes one input / output terminal, and another input / output terminal and two other ground terminals are provided on the left rear side in the figure. On the inner bottom surface of the case 1, the inner ends of the two input / output terminals are exposed. Reference numeral 5 denotes a ferrite plate which is a ferrimagnetic material, 7a, 7
b denotes a capacitor having upper and lower surfaces in the figure as electrodes, and 8 denotes a chip resistor. Reference numeral 9 denotes a lower yoke made of a ferromagnetic material. Inside the case 1, capacitors 7a and 7b and a chip resistor 8 are arranged, respectively, and the ferrite plate 5 is housed in a recess formed by the case 1 and the lower yoke 9. 1
Reference numeral 4 denotes an insulating substrate, and a first center electrode 4 intersecting the upper and lower surfaces thereof at a predetermined intersection angle within a range of 90 degrees to 100 degrees.
a and the second center electrode 4b. One ends of the two center electrodes 4a and 4b are drawn out to the lower surface in the drawing via through holes. The other ends are connected via through holes. This substrate 1
No. 4 is formed by patterning a high-frequency circuit board in which copper foil is stuck on both surfaces of an insulating base material. 6
Is a magnet for applying a static magnetic field to the center electrodes 4a, 4b and the ferrite plate 5. Reference numeral 10 denotes an upper yoke made of a ferromagnetic material, and a magnet 6 is attached to an inner surface (a lower surface in the drawing) of the upper yoke 10.

Each part is constituted as described above, the ferrite plate 5 is housed inside the case 1, the capacitors 7 a and 7 b are mounted, and the capacitors 7 a and 7 b are sandwiched between the case 1 and the substrate 1. 14 is placed. The chip resistor 8 is mounted on the lower surface of the substrate 14 in the drawing so as to connect the respective ends of the first and second center electrodes 4a and 4b. Then, the lower yoke 9 is attached to the lower portion of the case 1 and the upper yoke 10 to which the magnets 6 are attached in advance is put on, thereby forming an isolator as a whole.

FIG. 2 is a sectional view of a main part of the isolator. As shown in this figure, the solder resist film 11 is formed on the entire surface of both surfaces of the substrate 14. Therefore, the first
The solder resist film 11 exists on the surfaces of the center electrode 4a and the second center electrode 4b. Therefore, even if the magnet 6 is in close contact with the substrate 14, the magnet 6 and the first center electrode 4 a are separated by the thickness of the solder resist film 11. In addition, the distance between the center electrode and the upper yoke (not shown) is the same as that of the solder resist film. Similarly, the space between the ferrite plate 5 and the second center electrode 4b is separated by at least the thickness of the solder resist film 11. The thickness of the solder resist film 11 is 50 μm or more, and the thickness of the first and second center electrodes is 30 μm or more.

FIG. 12A shows the result of obtaining the relationship between the distance between the magnet and the center electrode and the insertion loss (IL).
Shown in When the distance between the magnet and the center electrode is short, high-frequency current due to eddy current flows through the magnet, and power is consumed by the electric resistance of the magnet. Further, the magnet has a dielectric tangent (tan).
Since δ) is large, when the magnet is brought into close contact with the center electrode, the dielectric loss increases. Further, as the distance between the yoke and the center electrode becomes smaller, a high-frequency current due to the eddy current flows, and power is consumed by the electric resistance of the yoke. These causes increase insertion loss.

To reduce this loss, the center electrode and the magnet and the center electrode and the yoke are separated by a solder resist film, but the outer dimensions are 5 mm × 5 mm × 2 m
When the thickness of the solder resist film is changed in the isolator m, the insertion loss (IL) changes as shown in FIG. As described above, as the thickness of the solder resist film increases, the insertion loss (IL) decreases, but the insertion loss (IL) rapidly saturates in the vicinity of more than 50 μm. When the thickness of the solder resist film is 50 μm, the insertion loss is 1.3 d.
B. In addition, the insertion loss required for the isolator having the above outer dimensions is generally within 1.3 dB. Therefore,
The thickness of the solder resist film 11 is 50 μm or more.

Next, the thickness of the center electrode and the insertion loss (IL)
FIG. 12 (B) shows the result of obtaining the relationship with. Here, the thickness of the solder resist film is set to 50 μm described above. As the thickness of the center electrode increases, the electrical resistance decreases (Q increases), so that the insertion loss decreases. When the thickness of the center electrode is changed, the insertion loss (IL) changes as shown in FIG. Thus, as the thickness of the center electrode increases, the insertion loss (I
L) decreases, but saturates abruptly in the vicinity of more than 30 μm. When the thickness of the center electrode is 30 μm, the insertion loss is 1.3 dB. Further, as described above, the required insertion loss is generally within 1.3 dB, so that the thickness of the center electrodes 4a and 4b is set to 30 μm or more. However, in order to make the height of the isolator as thin as possible, the center electrode 4
The thicknesses a and 4b are set to 30 μm or a thickness close thereto.

FIG. 3 is a circuit diagram of the isolator.
However, in this example, the ferrite plate 5 is drawn in a disk shape. As shown in the drawing, a first center electrode 4a is connected between the input terminal 2a and the ground terminal 3, a second center electrode 4b is connected between the output terminal 2b and the ground terminal 3, and the input terminal A capacitor C1 is connected between the output terminal 2a and the ground terminal 3, a second capacitor C2 is connected between the output terminal 2b and the ground terminal 3, and a resistor R is connected between the input terminal 2a and the output terminal 2b. It becomes a connected circuit.

FIG. 4 is a circuit diagram for explaining the operation principle of the isolator, and FIG. 5 is an equivalent circuit diagram of the isolator. In FIG. 4, the arrow indicates the direction of the high-frequency magnetic field below the center electrode. Now, considering the transmission of a forward signal, FIG.
(A), both ends of the resistor R have the same phase and the same amplitude, no current flows through the resistor R, and the input signal from the input terminal 2a is output from the output terminal 2b as it is.

Considering the incidence of a signal in the opposite direction, the direction of the high frequency magnetic field passing through the ferrite plate 5 is opposite to that in the case of (A) as shown in FIG. An out-of-phase signal is generated and power is consumed by the resistor R. Therefore, ideally, no signal is output from the input terminal 2a.

Actually, the phase difference between both ends of the resistor between the forward transmission and the reverse incidence of the signal is determined according to the intersection angle of the center electrodes 4a and 4b and the rotation angle of the polarization plane due to the Faraday rotation. Change. Therefore, insertion loss is small and high isolation characteristics can be obtained.
The intersection angle between the intensity of the external magnetic field and the center electrodes 4a and 4b is determined. The strength of the magnetic field applied to the ferrite plate is usually 0.
09 to 0.17 [T], the center electrodes 4a, 4b
Is set within the range of 90 degrees to 100 degrees, insertion loss is small and high isolation characteristics can be obtained.

The above operation is performed in the equivalent circuit of FIG.
This means that the phase difference between S12 (backward propagation signal) and S21 (forward transmission signal) when the resistance R is removed becomes 180 °. If there is a difference between the inductances L1 and L2 of the center electrodes 4a and 4b, the phase difference will deviate from 180 °. The deviation of the phase difference is suppressed. Therefore, even if the amplitude difference between S21 and S12 is about 0.2 dB, the above-mentioned capacitors 7a and 7b (C1, C2) are used in order to theoretically make the isolation 30 dB or more.
Are made substantially equal at ± 0.05 (5%). Thereby, even if the pattern formation dimensions of the first and second center electrodes vary, good isolation characteristics can be obtained.

FIG. 6 compares the insertion loss characteristics of the isolator according to this embodiment and the conventional isolator. A is the isolator according to this embodiment,
B shows the case of an isolator having no solder resist film on the substrate surface. As described above, by separating the center electrode and the magnet by the solder resist film on the substrate surface, insertion loss can be reduced over a wide frequency range.

Next, the configuration of an isolator according to a second embodiment will be described with reference to FIG. FIG. 7 is a cross-sectional view of a main part of the isolator according to the second embodiment, which is shown corresponding to FIG. 2 shown as the first embodiment. In this example, the insulating film 13 is attached to the surface of the magnet 6 facing the substrate. No solder resist film is formed on the surfaces of the center electrodes 4a and 4b on both sides of the substrate 14. Even with such a structure, the magnet 6 and the center electrode 4a can be separated at least by the thickness of the insulating film 13, so that the power loss due to the magnet 6 is suppressed and the insertion loss characteristics are improved. You. In the structure shown in FIG. 7, a solder resist film may be formed on the surface of the substrate 14 on which the center electrodes 4a and 4b are formed. This allows
The magnet 6 and the center electrode 4a can be separated by a predetermined distance depending on the thickness of the solder resist film and the thickness of the insulating film 13.

Next, the structure of an isolator according to a third embodiment will be described with reference to FIGS. FIG. 8 is an exploded perspective view of the isolator. Here, reference numeral 1 denotes a resin case in which the input / output terminal and the ground terminal 3 are insert-molded. Reference numeral 2b denotes one input / output terminal, and another input / output terminal and two other ground terminals are provided on the left rear side in the figure. On the inner bottom surface of the case 1, the inner ends of the two input / output terminals are exposed.
Reference numeral 5 denotes a ferrite plate made of a ferrimagnetic material, 7a and 7b denote capacitors having upper and lower surfaces as electrodes, and 8 denotes a chip resistor. Inside the case 1, capacitors 7a and 7
The ferrite plate 5 is housed in a recess formed by the case 1 and the lower yoke. Reference numerals 4a and 4b denote center electrodes made of copper foil, respectively, and are provided so as to cross the diagonal direction of the ferrite plate 5 at a predetermined crossing angle from the upper surface to the lower surface of the ferrite plate 5. Reference numeral 6 denotes a magnet for applying a static magnetic field to the center electrodes 4a and 4b and the ferrite plate 5. Reference numeral 10 denotes an upper yoke made of a ferromagnetic material.
The magnet 6 is stuck to the inner surface (lower surface in the figure) of the “0”. Reference numeral 12 denotes an insulating spacer formed of a resin plate having a predetermined thickness, and separates the magnet 6 from the center electrodes 4a and 4b. Reference numeral 9 denotes a lower yoke made of a ferromagnetic material.

The components are configured as described above, and the capacitors 7a and 7b and the chip resistor 8 are mounted inside the case 1, and the center electrodes 4a and 4b are mounted together with the ferrite plate 5. In this state, the capacitors 7a and 7b are sandwiched between the electrodes in the case 1 and the center electrodes 4a and 4b. Then, the lower yoke 9 is attached to the lower portion of the case 1 and the upper yoke 10 to which the magnets 6 are attached in advance is put on, thereby forming an isolator as a whole.

FIG. 9 is a sectional view of a main part of the isolator. However, in this drawing, the lower yoke 9 and the upper yoke 10 are omitted. As shown in FIG.
a and 4b are insulated by an insulating film 15. The insulating spacer 12 is arranged so as to be sandwiched between the ends of the center electrodes 4a and 4b and the magnet 6, and the magnet 6 and the center electrode 4
b is kept at a predetermined interval.

Although the input / output impedance of the isolator changes depending on the thickness of the ferrite plate 5 and the length of the center electrode, the impedance is matched with the impedance of the input / output line to reduce the loss due to impedance mismatch. In this example, the ferrite plate 5 having a thickness such that the bottom surface of the ferrite plate 5 is located above the bottom surface of the case 1 is used. The electrode may be closely attached to the lower yoke.

FIG. 10 is a diagram showing the frequency characteristics of the isolator, and FIG. 11 is a diagram showing the frequency characteristics of the isolator as a comparison. 10 and 11, (A) shows the input reflection characteristics (S11), (B) shows the transmission characteristics (S21), and (C) shows the isolation characteristics (S1).
2) and (D) show output reflection characteristics (S22).

Here, the isolator having the characteristics shown in FIG. 10 has a crossing angle of two center electrodes of 90 degrees and a resistor connected between the input and output as shown in FIG. The isolator having the characteristics shown in FIG.
It has three 0-degree center electrodes, and one end of the third center electrode is grounded via a resistor. The dimensions of the ferrite plates used in the two isolators are the same.

As described above, by using two center electrodes and making the intersection angle narrower than 120 degrees, good isolation characteristics can be obtained over a wide band. In the present invention, such two center electrodes are used. By using an electrode and reducing the insertion loss in an isolator having an intersection angle narrower than 120 degrees, the insertion loss can be reduced over a wide frequency band, and good isolation characteristics can be obtained over a wide band. it can.

Next, the configuration of the communication device will be described with reference to FIG. Using the above various isolators, for example, as shown in FIG. 13A, an isolator is provided in an oscillation output section of an oscillator such as a VCO, and a reflected wave from a transmission circuit connected to the output section of the isolator is applied to the oscillator. Avoid incidence. This increases the oscillation stability of the oscillator.

As shown in FIG. 13B, an isolator is provided at the input of the filter, and the isolator is used for matching. This constitutes a constant impedance filter. Such a circuit is provided in the transmission / reception circuit unit to constitute a communication device.

In each of the above-described embodiments, an example of using as an isolator has been described. However, a gyrator (non-reciprocal phase shifter) having a characteristic in which a phase delay differs depending on a transmission direction between two ports is described. Can be obtained by removing the chip resistor 8 (the resistor R in the equivalent circuits shown in FIGS. 3 and 4) described in the embodiment.

[0043]

According to the first aspect of the present invention, the close contact between the center electrode and the magnet is avoided, the coupling between the high frequency magnetic field and the magnet by the first or second center electrode is weakened, and the magnet is induced by the magnet. Loss due to high-frequency current is also reduced.

According to the second aspect of the present invention, since the insulating spacer can be provided only by coating the substrate on which the conductor pattern is formed with the resist film, the entire structure is simplified and the number of parts can be reduced. .

According to the third aspect of the invention, the mounting structure of the resistor is simplified, and the isolator can be easily configured.

According to the fourth aspect of the invention, the conductor loss due to the center electrode itself is suppressed, and the conductor loss due to the magnet is also efficiently suppressed. Therefore, the insertion loss can be efficiently reduced as a whole.

According to the fifth aspect of the present invention, since the insulating film in which the insulating film is attached to the magnet is used as the insulating spacer between the magnet and the center electrode, the structure for holding the insulating spacer is simplified. Assembly is also easy.

According to the sixth aspect of the invention, low insertion loss and high isolation characteristics can be obtained.

According to the seventh aspect of the present invention, the center electrode is arranged at a diagonal of the ferrimagnetic material, and the long center electrode can be efficiently arranged. A loss characteristic is obtained. In addition, since it can be configured by a method of cutting out from a plate-shaped or rectangular parallelepiped ferrimagnetic material, its manufacture is facilitated.

According to the present invention, even if there is a difference between the inductances of the first and second center electrodes, the phase of the forward transmission signal from the input terminal to the output terminal and the input from the output terminal to the input terminal are different. The difference from the phase of the reverse transmission signal to the terminal is 180
And the desired isolation characteristics can be obtained.

According to the ninth aspect of the present invention, the first and second center electrodes and the capacitor are shielded at the ground potential together with the yoke. Therefore, generation of spurious is suppressed.

According to the tenth aspect of the present invention, the separation of the yoke from the center electrode suppresses the high-frequency current generated in the yoke, increases the Q, and reduces the insertion loss.

According to the eleventh aspect of the present invention, since the ground connection is strengthened and unnecessary inductance and capacitance components are suppressed, the direct wave is reduced and the bandwidth is widened.

According to the twelfth aspect of the present invention, a non-reciprocal circuit element having an isolation characteristic is provided at an output part of an oscillation circuit or an input part of a filter, for example, so that communication with low loss and stable characteristics can be achieved. A device is obtained.

[Brief description of the drawings]

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

FIG. 2 is a sectional view of a main part of the isolator.

FIG. 3 is a circuit diagram of the isolator.

FIG. 4 is a circuit diagram for explaining the operation principle of the isolator.

FIG. 5 is an equivalent circuit diagram of the isolator.

FIG. 6 is a diagram showing an example of insertion loss characteristics of the isolator and a conventional isolator.

FIG. 7 is a sectional view of a main part of an isolator according to a second embodiment.

FIG. 8 is an exploded perspective view of an isolator according to a third embodiment.

FIG. 9 is a sectional view of a main part of the isolator.

FIG. 10 is a diagram showing frequency characteristics of the isolator.

FIG. 11 is a diagram showing frequency characteristics of a conventional isolator as a comparative example of the isolator according to the third embodiment.

FIG. 12 shows the relationship between the thickness of the solder resist film and the insertion loss,
Showing the relationship between the thickness of the center conductor and the insertion loss

FIG. 13 is a block diagram illustrating a configuration of a main part of a communication device according to a fourth embodiment.

[Explanation of symbols]

 1-case 2-input / output terminal 3-ground terminal 4-center electrode 5-ferrite plate 6-magnet 7-capacitor 8-chip resistor 9-lower yoke 10-upper yoke 11-solder resist film 12-insulating spacer 13-insulation Film 14-substrate 15-insulating film

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshihiro Makino 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (72) Takao Nakata 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Stock Company Murata Manufacturing F-term (reference) 5J013 EA01 FA03

Claims (12)

[Claims] A first center electrode having one end connected to the input terminal, the other end intersected with the grounded first center electrode in an insulated state, and one end connected to the output terminal;
A second center electrode having the other end grounded, a ferrimagnetic body close to the first and second center electrodes, a magnet for applying a static magnetic field substantially perpendicular to the ferrimagnetic body, A first capacitor connected to the input terminal and having the other end grounded;
A second terminal having one end connected to the output terminal and the other end grounded;
A non-reciprocal circuit device comprising: a capacitor; and an insulating spacer provided between the magnet and the first or second center electrode. 2. The method according to claim 1, wherein the first and second center electrodes are constituted by conductor patterns provided on both surfaces of the substrate, and the insulating spacer is constituted by a resist film formed on the surface of the conductor pattern. The non-reciprocal circuit device according to claim 1. 3. The non-reciprocal circuit device according to claim 2, wherein a resistor connected between the input terminal and the output terminal is mounted on the substrate. 4. The conductive pattern is made of a metal foil having a thickness of 30 μm or more, and the thickness of the resist film is set to 50 μm.
The non-reciprocal circuit device according to claim 2, wherein: 5. The non-reciprocal circuit device according to claim 1, wherein the insulating spacer is formed of an insulating film attached to the magnet. 6. An intersection angle between said first and second center conductors is set to a predetermined angle within a range of 90 degrees to 100 degrees.
6. The non-reciprocal circuit device according to any one of items 1 to 5, 7. The non-reciprocal circuit device according to claim 1, wherein said ferrimagnetic material is formed in a substantially rectangular parallelepiped shape. 8. The non-reciprocal circuit device according to claim 1, wherein the first and second capacitors have substantially equal capacitance values. 9. A magnetic circuit for shielding the first and second center electrodes, the ferrimagnetic material, the magnet, and the first and second capacitors, respectively, and for applying the static magnetic field. 9. The non-reciprocal circuit device according to claim 1, wherein the yoke is surrounded by a yoke, and the yoke is set at a ground potential. 10. The non-reciprocal circuit device according to claim 9, wherein an insulator layer is provided between the yoke and the center electrode. 11. A plurality of ground terminals are provided,
2. The case according to claim 1, wherein at least two ground terminals and the input terminal are provided on one side of the case, and at least two other ground terminals and the output terminal are provided on the other side of the case. 10. The non-reciprocal circuit device according to any one of claims 1 to 10. 12. A communication device using the non-reciprocal circuit device according to claim 1.