JPH11298205A - Irreversible circuit element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an irreversible circuit element with which unwanted radiation can be reduced by enlarging the amount of attenuation outside frequency bands by avoiding price-up and expansion and further current consumption can be reduced by reducing load fluctuation. SOLUTION: Concerning a centralization constant type isolator (nonreversible circuit element) 1 with which a magnet 6 impresses a DC magnetic field to a magnetic assembly 4 formed by arranging plural central conductors 8-10 across a ferrite 7, an inductor L1 of a circuit element consisting of a band pass filter is incorporated at an input port Pi of the central conductor 8 at least. Besides, this inductor L1 is formed on a dielectric spacer 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nonreciprocal circuit device used in a microwave band, for example, an isolator and a circulator.

[0002]

2. Description of the Related Art Conventionally, a lumped constant type isolator of this type has a structure shown in FIG. This lumped-constant isolator 50 mainly includes a case 51
A magnetic assembly 56 including a terminal block 53 in which matching capacitors Co to Co and a terminating resistor R are disposed in a magnetic circuit including a cap 52 and a permanent magnet 58, three center conductors 54, and a ferrite 55. At the same time, a dielectric spacer 57 for pressing and fixing the magnetic assembly 56 electrically and mechanically is disposed.
Are arranged.

As shown in the equivalent circuit diagram of FIG. 11, the isolator 50 has ports P1 to P3 of each central conductor 54.
, A matching capacitor Co is connected to one port P3
Is connected to a terminating resistor R.

[0004] Such an isolator has such a characteristic that the amount of attenuation is small for a signal in a forward direction and the amount of attenuation is large for a signal in a reverse direction. For example, the isolator is used in a transmission circuit of a communication device such as a mobile phone. Have been.

By the way, the amplifier incorporated in the above-mentioned communication equipment has a linear distortion of harmonics, which causes unnecessary radiation (spurious, especially a second or third harmonic of a fundamental wave). Since this unnecessary radiation causes interference and abnormal operation of the power amplifier, it is required to keep the unnecessary radiation below a certain level. In order to prevent the generation of the unnecessary radiation, an amplifier having excellent linearity may be employed, or a separate filter may be employed to attenuate the unnecessary wave.

[0006]

However, an amplifier having good linearity is expensive, and when a filter is separately employed, the cost increases as the number of components increases and the size of the entire communication device increases. Occurs. For this reason, it is difficult to adopt it for communication devices such as mobile phones, which are strongly demanded for miniaturization and price reduction.

In addition, the current consumption of the amplifier is liable to change remarkably due to a change in the load of the output portion thereof, and in an extreme case, there is a possibility of transmission. For this reason, it is required to suppress the load fluctuation of the output unit within the band as much as possible.

Here, an isolator or a circulator is used on the output side of the amplifier for stable operation and protection of the amplifier in the communication equipment. In particular, lumped-constant isolators and circulators have a band-pass filter function as a forward characteristic, and therefore have a feature that the attenuation is large even in the forward direction in a frequency band farther from the pass band.

It is conceivable to attenuate unwanted waves by utilizing such out-of-band characteristics. However,
Since the above-mentioned isolator is not originally intended to obtain attenuation outside the band, there is a limit in exhibiting its performance, and improvement in this respect is required.

The present invention has been made in view of such a conventional situation, and it is possible to reduce unnecessary radiation by increasing the amount of attenuation outside a frequency band while avoiding an increase in price and size. It is an object of the present invention to provide a non-reciprocal circuit device capable of reducing load consumption by reducing load fluctuation.

[0011]

According to a first aspect of the present invention, there is provided a non-reciprocal circuit device in which a DC magnetic field is applied by a magnet to a magnetic assembly having a plurality of center conductors crossed over a ferrite. At least a part of a circuit element constituting a band-pass filter is incorporated in an input port of the center conductor.

According to a second aspect of the present invention, a magnet is arranged with a dielectric substrate interposed in a magnetic assembly having a plurality of center conductors intersected with ferrite, and a direct current magnetic field is applied to the magnetic assembly by the magnet. A non-reciprocal circuit element that applies at least a part of a circuit element constituting a band-pass filter at an input port of the center conductor, and the circuit element is formed on the dielectric substrate. And

According to a third aspect of the present invention, in the second aspect, one of a series inductor and a series capacitor of a circuit element constituting the bandpass filter is formed on the dielectric substrate, and the other is a nonreciprocal circuit element. It is characterized by being formed outside.

According to a fourth aspect of the present invention, in the second aspect, both the series inductor and the series capacitor of the circuit element constituting the band-pass filter are formed on the dielectric substrate.

According to a fifth aspect of the present invention, in any one of the second to fourth aspects, the dielectric substrate is constituted by a laminated substrate.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 to FIG.
FIGS. 1A and 1B are views for explaining a lumped-constant isolator according to one embodiment of the present invention; FIG. 1 is an exploded perspective view of the isolator; FIG. 2A is a plan view of an inductor formed on a dielectric spacer; 2B is a perspective plan view of an electrode formed on the back surface of the dielectric spacer, and FIG. 3 is an equivalent circuit diagram of the isolator.

In FIG. 1, reference numeral 1 denotes a lumped constant type isolator, in which a terminal block 3 is disposed on a bottom surface 2a of a case 2 made of a magnetic metal, and a magnetic assembly 4 is disposed on the terminal block 3. A box-shaped cap 5 also made of a magnetic metal is attached to the case 2 and a rectangular permanent magnet 6 is attached to the inner surface of the cap 5 to form a magnetic circuit. It is configured to apply a DC magnetic field to the assembly 4.

In the magnetic assembly 4, three center conductors 8, 9, and 10 are arranged on the upper surface of the disk-shaped ferrite 7 so as to intersect at an angle of 120 degrees with an insulating sheet (not shown) interposed therebetween. Each of the center conductors 8 to
It has a structure in which the grounding portion 11 is in contact.

The terminal block 3 is made of an electrically insulating resin and has a structure in which a bottom wall 3b is integrally formed with a rectangular frame-shaped side wall 3a, and an insertion hole 3c is formed in the bottom wall 3b. At the periphery of the insertion hole 3c of the bottom wall 3b, a concave portion 3d for accommodating the single-plate type matching capacitors 12a to 12c and the single-plate type termination resistor R is formed. The magnetic assembly 4 is inserted into the insertion hole 3c, and the ground portion 11 of the magnetic assembly 4 is connected to the bottom surface 2a of the case 2.

Input and output terminals 15 and a ground terminal 16 for surface mounting are formed on the outer surfaces of the left and right side walls 3a of the terminal block 3. The input and output terminals 15 are connected to the bottom wall 3a.
It is led out to the corner on the upper surface of b. The ground terminal 16 is led out to the upper surface of each of the recesses 3d,
The lower electrodes of the capacitors 12a to 12c and one end of the terminating resistor R are connected. These terminals 15, 16
Is formed by insert-molding a part in the terminal block 3.

The input / output ports P1 to P3 of the central conductors 8 to 10 are connected to the upper electrodes of the capacitors 12a to 12c, respectively. The tip of the port P1 is connected to the input terminal 15 and the tip of the port P2. Is connected to the output terminal 15, and the tip of the port P3 is connected to the terminating resistor R.

On the upper surface of the magnetic assembly 4, a rectangular thin plate-shaped dielectric spacer 18 is provided. This spacer 1
Reference numeral 8 denotes the case where the cap 5 is mounted on the case 2 and the magnetic assembly 4 and the terminal block 3 are connected via the permanent magnet 6 to the case 2.
The ports P1 to P3 of the center conductors 8 to 10 are electrically and mechanically pressed and fixed to the capacitors 12a to 12c, respectively. A hole 18a is formed at the center of the spacer 18 corresponding to the magnetic assembly 4, and a notch 18 is formed at a corner corresponding to the terminating resistor R.
b is formed.

On the upper surface of the spacer 18, FIG.
As shown in FIGS. 2A and 2B, a series inductor L1 as a circuit element 20 constituting a bandpass filter is formed in a pattern. One end of the inductor L1 is connected via a through-hole electrode 21 to the connection land electrode 2 on the back surface.
2 and the other end is also a through-hole electrode 2
3 is connected to the input land electrode 24 on the back surface.

The connection land electrode 22 is connected to the capacitor 12a, and the input land electrode 24 is connected to the center conductor 8
Is connected to the input port P1. Thereby, one series inductor L1 which is a component of the band-pass filter is added to the input port P1. A series capacitor C1 as the other component is formed outside the isolator 1, and the inductor L1 and the capacitor C1
1 form a bandpass filter (BPF) (see the equivalent circuit diagram in FIG. 3).

Next, the operation and effect of this embodiment will be described. According to the lumped constant type isolator 1 of the present embodiment,
Since the inductor L1 is formed in a pattern on the dielectric spacer 18 and a bandpass filter is formed by the inductor L1 and the external capacitor C1, the band outside the operating frequency band of the isolator 1, especially on the high frequency side (2nd harmonic, 3rd harmonic, 3rd harmonic). Harmonic)
, The amount of attenuation can be increased, and harmonic distortion and unnecessary radiation can be reduced. In addition, since a part of the circuit element of the filter is built in the input port P1, a band-pass filter can be formed with a simple structure and at a low cost. Can contribute to

The input port P1 of the isolator 1
, A load fluctuation in the band of the input port P1 of the isolator 1, that is, the output section of the amplifier, can be reduced, the current consumption of the amplifier can be reduced, and the operation of the amplifier can be stabilized. Can contribute to higher performance.

Since the inductor L1 is formed on the spacer 18, the band-pass filter can be formed by effectively utilizing the existing components of the isolator 1, and this also contributes to downsizing.

In the above-described embodiment, the case where the series inductor L1 of the circuit element 20 is built in the isolator and the series capacitor C1 is externally described has been described. May be externally provided, and in this case, the same effect as in the above embodiment can be obtained.

FIGS. 4 and 5 are characteristic diagrams showing the results of experiments conducted to confirm the effect of the lumped-constant isolator.

In FIG. 4, the dashed line indicates the pass characteristics of the isolator of the present embodiment, and the solid line indicates the pass characteristics of the conventional isolator. As can be seen from the figure, the isolator of the present embodiment has a greater attenuation outside the frequency band than the conventional one due to the addition of the band-pass filter.

In FIG. 5, the dashed line indicates the input impedance of the isolator of the present embodiment, and the solid line indicates the input impedance of the conventional isolator. As can be seen from the figure, according to the present embodiment, the addition of the band-pass filter reduces the load fluctuation in the band at the input port compared to the related art.

FIGS. 6 to 8 are views for explaining a lumped-constant isolator according to an embodiment of the present invention. FIG. 6 is an exploded perspective view of the isolator, and FIG.
4A is a plan view showing an inductor and a capacitor formed on a spacer, FIG. 4B is a perspective plan view showing a capacitor formed on the back surface of the spacer, and FIG. 8 is an equivalent circuit diagram thereof. In the drawings, the same reference numerals as those in FIGS. 1 to 3 indicate the same or corresponding parts.

Lumped constant type isolator 1 of the present embodiment
In this case, the terminal block 3 is arranged in the case 2 and the magnetic assembly 4 is arranged. The cap 5 on which the permanent magnet 6 is adhered is mounted on the case 2, and the DC is applied to the magnetic assembly 4 by the permanent magnet 6. Is configured to apply a magnetic field,
The basic structure is the same as the above embodiment.

In the present embodiment, the dielectric spacer 18
The first electrode 30 and the second electrode 31 of the series inductor L1 as a circuit element constituting the band-pass filter and the series capacitor C1 are pattern-formed on the upper surface of the filter.

One end of the inductor L1 is connected to a matching capacitor 12a via a through-hole electrode 21 and a connection land electrode 22. In addition, the inductor L1
Is connected to the first electrode 30, and the second electrode 31 facing the first electrode 30 with the spacer 18 interposed therebetween is connected to the input port P <b> 1 via the input land electrode 24.

Thus, the input port P1 incorporates a series inductor L1 and a series capacitor C1, which are components of a band-pass filter (see the equivalent circuit diagram of FIG. 8).

Also in this embodiment, since the band-pass filter is formed by the inductor L1 and the capacitor C1 formed on the spacer 18, the attenuation in the frequency band can be increased, and the harmonic distortion and unnecessary radiation can be reduced. This can contribute to downsizing and cost reduction by eliminating the need for an expensive amplifier or a separate filter, and achieve the same effects as in the above embodiment.

The input port P1 of the isolator 1
Since a band-pass filter is built in the amplifier, load fluctuations in the band can be reduced, the current consumption of the amplifier can be reduced, and the operation of the amplifier can be stabilized. From this point, the same effects as those of the above embodiment can be obtained.

In this embodiment, since both the series inductor L1 and the series capacitor C1 are formed by effectively utilizing the free space of the spacer 18, the number of parts is reduced and the cost is reduced as compared with the case where the capacitor C1 is externally mounted. Thus, the mounting area can be reduced, which contributes to downsizing of communication devices.

FIG. 9 is an exploded perspective view for explaining an isolator according to one embodiment of the fifth aspect of the present invention, in which the same reference numerals as those in FIG. 7 denote the same or corresponding parts.

In this embodiment, the inductors L are provided on the upper surfaces of the first, second, and third dielectric spacers 35, 36, and 37, respectively.
1, the first electrode 30 and the second electrode 31 of the capacitor are formed in a pattern, and the respective spacers 35 to 37 are laminated and connected to each other via the through-hole electrode 21.

In this embodiment, the effect of increasing the attenuation in the frequency band and reducing the load fluctuation in the band can be obtained as in the above-described embodiment. In addition, the inductor L1, the series capacitor first and second electrodes 30, 31 are pattern-formed on the upper surfaces of the first to third spacers 35 to 37, respectively, and are laminated and integrated. As compared with the case of forming a pattern, manufacturing is easier, cost can be reduced, and an inexpensive isolator can be provided.

Although both the series inductor L1 and the electrodes 30 and 31 of the series capacitor are formed, it is also possible to form only one of the present invention and the other externally.

In each of the above embodiments, the lumped-constant type isolator has been described as an example. However, the present invention can of course be applied to a circulator.

[0045]

As described above, according to the nonreciprocal circuit device according to the first aspect of the present invention, since the circuit element constituting the band-pass filter is built in the input port, harmonic distortion and unnecessary radiation outside the frequency band are provided. This makes it possible to form a band-pass filter with a simple structure and at low cost, and to contribute to miniaturization and cost reduction by eliminating the need for an expensive amplifier or a separate filter.

Further, since a band-pass filter is added to the input port, load fluctuation in the band can be reduced, current consumption of the amplifier can be reduced, operation can be stabilized, and there is an effect that it is possible to contribute to high performance of communication equipment.

According to the second aspect of the present invention, since the circuit element constituting the band-pass filter is formed on the dielectric substrate, existing parts that are components of the non-reciprocal circuit element can be effectively used.
This has the effect of reducing costs and contributing to downsizing.

According to the third aspect of the invention, one of the series inductor and the series capacitor of the circuit element is formed on the dielectric substrate, and the other is formed outside the non-reciprocal circuit element.
The same effects as the first and second aspects are obtained.

According to the fourth aspect of the present invention, since both the series inductor and the series capacitor are formed on the dielectric substrate, the number of components can be reduced as compared with the case of externally attaching, and
There is an effect that the size can be reduced.

According to the fifth aspect of the present invention, since the dielectric substrate is constituted by a laminated substrate, the production can be facilitated and the cost can be reduced as compared with the case where electrodes are formed on both surfaces of one substrate.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view illustrating a lumped-constant isolator according to an embodiment of the present invention.

FIG. 2 is a view showing an inductor of a dielectric spacer of the isolator.

FIG. 3 is an equivalent circuit diagram of the isolator.

FIG. 4 is a characteristic diagram showing effects of the embodiment.

FIG. 5 is a characteristic diagram showing an effect of the embodiment.

FIG. 6 is an exploded perspective view of an isolator according to an embodiment of the present invention.

FIG. 7 is a diagram showing inductors and capacitors of the isolator.

FIG. 8 is an equivalent circuit diagram of the isolator.

FIG. 9 is an exploded perspective view showing a laminated substrate according to an embodiment of the present invention.

FIG. 10 is an exploded perspective view of a conventional general isolator.

FIG. 11 is an equivalent circuit diagram of a conventional isolator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lumped constant type isolator (non-reciprocal circuit element) 4 Magnetic assembly 6 Permanent magnet 7 Ferrite 8-10 Center conductor 18 Dielectric spacer 20 Circuit element L1 Series inductor C1 Series capacitor P1 Input port

Continued on the front page (72) Inventor Takashi Hasegawa 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A non-reciprocal circuit device in which a DC magnetic field is applied by a magnet to a magnetic assembly having a plurality of center conductors arranged to intersect a ferrite, wherein a band-pass filter is provided at an input port of the center conductor. A non-reciprocal circuit device, wherein at least a part of a circuit element to be configured is incorporated. 2. A magnetic assembly comprising a ferrite and a plurality of center conductors intersecting each other, a magnet disposed with a dielectric substrate interposed therebetween, and a direct current magnetic field applied to the magnetic assembly by the magnet. A non-reciprocal circuit device, characterized in that at least a part of a circuit element constituting a band-pass filter is built in an input port of the center conductor, and the circuit element is formed on the dielectric substrate. element. 3. The device according to claim 2, wherein one of a series inductor and a series capacitor of a circuit element constituting the bandpass filter is formed on the dielectric substrate, and the other is formed outside the nonreciprocal circuit element. A non-reciprocal circuit device. 4. The non-reciprocal circuit device according to claim 2, wherein both a series inductor and a series capacitor of the circuit element constituting the band-pass filter are formed on the dielectric substrate. 5. The non-reciprocal circuit device according to claim 2, wherein the dielectric substrate is constituted by a laminated substrate.