JP3331702B2 - Non-reciprocal circuit device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to VHF, UHF, SH
Regarding non-reciprocal circuit elements used in the F-band and the like, for example, isolators, in particular, it is possible to reduce the size and weight of components and to contribute to cost reduction while widening the isolation characteristics. Regarding the structure.

[0002]

2. Description of the Related Art Generally, an isolator has a function of passing a signal only in a transmission direction and preventing transmission in a reverse direction. For example, an isolator is used in a transmission circuit section of a mobile communication device such as a mobile phone and a car phone. Have been. This isolator is
As shown in FIG. 12, a terminating resistor R is connected to any one port P3 of the circulators of the three ports P1 to P3, the signal a from the port P1 is transmitted to the port P2, and It has a function of absorbing the incoming reflected wave b by the terminating resistor R to prevent transmission to the port P1, thereby preventing unnecessary waves from entering the power amplifier.

In the above isolator, the port P
Depending on the frequency of the reflected wave b entering from 2, there is a case where the reflected wave b cannot be absorbed, and as a result, the problem that the reflected wave b escapes to the port P1 occurs. In order to avoid such a problem, an attempt is made to broaden the isolation characteristic (reverse attenuation characteristic).

On the other hand, as shown in FIG.
To P3, a matching circuit 1 composed of L (inductance), C (capacitor) and the like is connected.
There is a method of widening the pass bandwidth of P3. However, if matching circuits 1 and 1 are provided on the lines of ports P1 and P2 through which signals pass, the loss increases and I.P. L. There is a problem that characteristics (pass characteristics) are deteriorated, and there is a problem that an increase in the number of parts and an increase in the size and weight of the parts are caused.

On the other hand, as shown in FIG. 10, between the terminating resistor R and the port P3 (see FIG. 10A) or between the terminating resistor R and the cold end (see FIG. )
It is conceivable that the matching circuit 1 is provided in FIG. In this case, the loss in the signal line can be reduced, and I.I.
L. Deterioration of the characteristics can be avoided, and reduction in size and weight can be achieved by reducing the number of parts.

FIGS. 5 to 9 show an example of a structure in which a matching circuit is provided to the terminating resistor. The isolator 2 mainly includes a ground plate 1 in magnetic yoke bodies 3 and 4 forming a magnetic closed circuit.
The matching capacitance substrate 5 and the ferrite element 6 are accommodated and arranged with the interposition of a ferrite element 6, and a DC magnetic field is applied to the ferrite element 6 by a permanent magnet 7 attached to the inner surface of the yoke 3. And a terminal board 8 is provided.

FIGS. 5 and 6 show that a matching circuit element 11 is constituted by the coil 9 and the disk type capacitor 10, and one end of the circuit element 11 is connected to a terminating resistance film 5 a of the capacitor substrate 5.
And the other end is connected to the yoke 4.

FIGS. 7 and 8 show a microstrip line 13 formed on the surface of a substrate 12 to form a matching circuit board 14, and the circuit board 14 is mounted on the yoke 3, One end of 13
This is an example in which 3a and the terminating resistance film 5a of the capacitance substrate 5 are connected via a metal plate 15, and the other end 13b is connected to the yoke 3 via a through-hole electrode. Further FIG.
Constitutes a matching circuit board 16 by superimposing boards on which a strip line (not shown) is formed.
This is an example of mounting on the upper part.

[0009]

However, in each of the above-described structural examples, since the matching circuit element and the matching circuit board are separately mounted on the yoke main body, the size and weight of the parts cannot be increased accordingly. Inevitably, there is a problem that it is impossible to cope with miniaturization and weight reduction, and improvement in this respect is demanded.

Further, when a matching circuit element using the above-mentioned coil and disk capacitor is employed, the constant tends to be unstable, so that it is necessary to adjust the electrical characteristics, which is troublesome, resulting in an increase in cost. There is.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can cope with downsizing and weight reduction of components while widening the isolation, and simplify the adjustment of electrical characteristics to reduce costs. It is intended to provide a non-reciprocal circuit device that can be used.

[0012]

According to the present invention, a plurality of center conductors are arranged in a ferrite to which a DC magnetic field is applied in a state of being electrically insulated from each other and crossing each other. A non-reciprocal circuit device having a capacitor connected thereto, a terminator connected to any one of the ports, and a matching circuit connected to the terminator so as to achieve a wider isolation characteristic. Electrical length is 1/4
A line having an integral multiple of λg (λg is a wavelength in the line) is used, and the line is formed as a strip line on a thin substrate, and a ground plane of the thin substrate also serves as a ground plate of the nonreciprocal circuit element It is characterized by having.

[0013]

According to the non-reciprocal circuit device of the present invention, a strip line having an electrical length of 1 / 4.lambda.g is connected to a terminator connected to one port, and the strip line is formed on a thin substrate by pattern formation. Since the ground plane of the thin substrate was also used as a ground plate, I.P. L. It is possible to broaden the isolation characteristic while avoiding the influence on the characteristic, and it is possible to reliably absorb the reflected wave and prevent an unnecessary wave from entering.

Further, since the thin substrate is also used as the ground plate, the existing substrate can be used as it is, so that the size, volume and weight of the component hardly increase.
Therefore, it is possible to cope with downsizing and weight reduction of parts as compared with the case where the above-mentioned matching circuit element or matching circuit board is separately mounted.

Further, in the present invention, since it is only necessary to manage the line length of the strip line, it is possible to configure a high-precision broadband circuit having less variation as compared with the case of using a circuit element including the coil and the disk capacitor. it can. Along with this, it is possible to simplify the electrical adjustment or to eliminate the adjustment, thereby reducing the cost and contributing to the cost reduction of parts.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIGS. 1 to 4 are diagrams for explaining a non-reciprocal circuit device according to one embodiment of the present invention. In this embodiment, a case where the present invention is applied to a lumped constant type isolator will be described as an example.

In the figure, reference numeral 20 denotes a lumped constant type isolator to which the structure of the present embodiment is applied. The isolator 20 includes a lower yoke 22 made of a substantially U-shaped magnetic metal disposed on a terminal board 21, and a bottom wall 22 a of the lower yoke 22.
A matching capacitance substrate 23 is provided on the lower yoke 22, and a magnetic metal upper yoke 2 is provided on the lower yoke 22.
5 to form a closed magnetic circuit. Further, a permanent magnet 26 is adhered to the inner surface of the upper yoke 25, and the permanent magnet 26 is configured to apply a DC magnetic field for bias to the ferrite element 24.

A ground electrode 36 is provided on the upper surface of the terminal board 21.
a is formed, and the lower surface of the lower yoke 22 is in contact with the ground electrode 36a. Ground terminal electrodes 37a and 37b connected to the ground electrode 36a are formed on the upper and lower surfaces of the left and right side edges of the terminal board 21, and the terminal electrodes 37a and 37b are connected to the side electrodes 38. Connected by

The input / output terminal electrodes 32a, 32a are provided on the upper and lower surfaces of the left and right side edges of the terminal board 21, respectively.
2b are formed, and the terminal electrodes 32a and 32b are connected to each other by a side electrode 39.

The ferrite element 24 is provided with a net-shaped first to third center conductors 27 and 2 on a disc-shaped shield (not shown).
9, a ferrite 30 for microwaves is disposed on the shield part, and the respective center conductors 27 to 29 are electrically insulated from each other on the upper surface of the ferrite 30.
It is structured to be bent and arranged to intersect at every 20 degree angle. Also, the external connection part 2 of each of the center conductors 27 to 29
Reference numerals 7a to 29a are bent and formed stepwise, and project outward.

The matching capacitor substrate 23 is a dielectric substrate 31
A first to third capacitor electrodes (matching capacitors) C1 to C3 are formed by thick-film printing on the periphery of the insertion hole 31a on the upper surface of the insertion hole 31a by thick-film printing. A terminating resistor film (terminator) R is connected to the three capacitor electrode C3 by thick film printing and formed.

The ferrite element 24 is inserted into the insertion hole 31a of the capacitor substrate 23, so that the lower surface of the ferrite 30 is connected to the bottom wall of the lower yoke 22 via the shields of the central conductors 27 to 29. 22a.

External connection portions 27a to 29a of the center conductors 27 to 29 are connected to the capacitor electrodes C1 to C3.
And the first and second center conductors 2
7, 27a, connection portions 27a, 28a, and tip portions 27b, 28
b denotes input / output terminal electrodes 32a, 32 of the terminal board 21.
b.

As shown in FIGS. 1 and 2, the ground substrate 40 is a thin substrate 33, which is a feature of this embodiment.
34 are stacked.

The ground substrate 40 is formed by laminating a thin ground plate 34 on top of a thin substrate 33 and thermocompressing the thin ground plate 34 on one side edge of the thin substrate 33 and the ground plate 34. The projections 33a and 34a are integrally formed to protrude. Ground electrodes 41 and 42 are pattern-formed on the upper surface of the ground plate 34 and the lower surface of the thin substrate 33, respectively, and the electrodes 41 and 42 are opposed to each other with the thin substrate 33 interposed therebetween.

A substantially semicircular side-surface through-hole electrode 43 is formed on each side of the ground substrate 40, and the ground electrodes 41 and 42 are connected to each other by the side-surface through-hole electrode 43. ing. The lower surface of the capacitor substrate 23 is in contact with the ground electrode 41 on the upper surface,
The ground electrode 42 on the lower surface is a bottom wall 22a of the lower yoke 22.
Abut on top.

On the upper surface of the thin substrate 33, microstrip lines 44 are formed in a pattern. The strip line 44 is a line having a line length that is an integral multiple of 1 / 4.lambda.g. One end 44a of the strip line 44 is connected to the ground electrode 41 via a side through-hole electrode 43 on one side of the substrate 33. , 42 are connected.

The other end 4 of the strip line 44
4b is a projection 33a, 34a of the ground substrate 40.
Through a through-hole electrode 45 formed in the ground plate 34 to the land electrode 46 of the ground plate 34. The land electrode 46 and the terminating resistance film R of the capacitor substrate 23 are connected by a metal plate 47 bent and formed in a hook shape.
Thus, the matching circuit for widening the band of the present embodiment is configured.

Next, the operation and effect of this embodiment will be described. According to the isolator 20 of the present embodiment, １ ／ · λ
g is formed on the thin substrate 33 and the substrate 33 is laminated together with the ground plate 34 to form the ground substrate 40. L. The isolation characteristic can be broadened while avoiding the influence on the characteristic, whereby the reflected wave can be surely absorbed and the invasion of the unnecessary wave can be prevented. Incidentally, in the present embodiment, the frequency band can be expanded to about 1.5 to 2 times.

In this embodiment, the isolator 20
Since the thin board 33 is built into the earth board 40 constituting the above and integrated therewith, the dimensions and size of the conventionally used earth board are reduced.
The volume and the weight can be made almost the same, and the size and weight of the parts can be reduced as compared with the case where the above-mentioned matching circuit is separately mounted.

In this embodiment, the strip line 4
Since the ground plane of No. 4 is also used as a ground plate, it can be shared by one component, and this also contributes to miniaturization and weight reduction. Here, the two earth electrodes 41 and 42 are used.
May be subjected to silver plating, and in such a case, the characteristics can be further improved.

Further, in this embodiment, since it is only necessary to set the line length of the strip line 44 so as to have the above-mentioned electrical length, a high variance is obtained as compared with the case where the matching circuit element is constituted by the above lumped constant. A high-precision broadband circuit can be configured. As a result, the electrical adjustment can be simplified or no adjustment can be made, so that the cost can be reduced and the cost of parts can be reduced.

In the above embodiment, the two thin substrates 3
Although the case where the earth substrate is formed by thermocompression bonding of 3, 34 has been described as an example, the present invention, for example, forms an electrode on a green sheet and forms an earth substrate by integrally firing the electrode and the green sheet. You may.

Further, in the above embodiment, an isolator in which a terminator is connected to a lumped constant type 3-port circulator has been described as an example. However, the present invention is not limited to this. Of course, the present invention can also be applied to a tube type non-reciprocal circuit device.

[0035]

As described above, according to the non-reciprocal circuit device according to the present invention, a strip line having an electric length of 1 / 4.lambda.g is connected to a terminator connected to one port and a thin plate substrate is connected. Since the ground plane of the thin substrate is also used as the ground plate constituting the non-reciprocal circuit device, the size and weight of the parts can be reduced while the isolation characteristics are broadened. There is an effect that can contribute.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view illustrating a ground board according to an embodiment of the present invention.

FIG. 2 is a perspective view of the ground substrate of the embodiment.

FIG. 3 is an exploded perspective view of the isolator of the embodiment.

FIG. 4 is a perspective view of the isolator of the embodiment.

FIG. 5 is an exploded perspective view of an isolator for explaining a process of establishing the present invention.

FIG. 6 is a perspective view of an isolator for explaining a process of establishing the present invention.

FIG. 7 is an exploded perspective view of an isolator for explaining a process of establishing the present invention.

FIG. 8 is a perspective view of an isolator for explaining a process of establishing the present invention.

FIG. 9 is a perspective view of an isolator for explaining a process of establishing the present invention.

FIG. 10 is a diagram showing an operation of an isolator for explaining a process of establishing the present invention.

FIG. 11 is a diagram illustrating an operation of an isolator for explaining a process of establishing the present invention.

FIG. 12 is a diagram showing an operation of a general isolator.

[Explanation of symbols]

 Reference Signs List 20 isolator (non-reciprocal circuit device) 27 to 29 center conductor 30 ferrite 33, 34 thin board 40 ground board 44 strip line R terminating resistor film (terminator)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01P 1/383 H01P 1/36

Claims (1)

(57) [Claims] A plurality of center conductors are arranged in a ferrite to which a DC magnetic field is applied in an electrically insulated state and cross each other, and a matching capacitor is connected to a port of each of the center conductors.
And connect a terminator to any one of the ports,
A non-reciprocal circuit device in which a matching circuit is connected to the terminator so as to widen an isolation characteristic, wherein the matching circuit has an electric length of 1 / 4.lambda.g (.lamda.g is a line wavelength). A non-reciprocal circuit device, wherein a doubled line is used, and the line is formed as a strip line on a thin substrate, and a ground plane of the thin substrate also serves as a ground plate of the non-reciprocal circuit device. .