JPH11298206A - Irreversible circuit element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an irreversible circuit element with which an insertion loss can be reduced in the case of forming a circuit element consisting of a band pass filter on a dielectric substrate. SOLUTION: Concerning a centralization constant type isolator (irreversible circuit element) 1 with which a magnet 6 is arranged while interposing a dielectric substrate 18 on a magnetic assembly 4 formed by arranging plural central electrodes 8-10 across a ferrite 7 and a DC magnetic field is impressed to the magnetic assembly 4 by the magnet 6, an inductor (circuit element) L1 consisting of the band pass filter is formed on the dielectric substrate 18, and a dielectric film 25 is held between the inductor L1 on the dielectric substrate 18 and the magnet 6.

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 Generally, non-reciprocal circuit devices such as lumped-constant isolators and circulators have a characteristic that a forward signal has a small attenuation and a reverse signal has a large attenuation. For example, it is employed in a transmission circuit unit of a communication device such as a mobile phone.

Incidentally, linear distortion is present in an amplifier incorporated in the above-mentioned communication equipment, and this causes unnecessary radiation (spurious, particularly, second and third harmonics 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.

[0004] However, an amplifier having good linearity is expensive, and when a filter is separately employed, there is a problem in that the cost increases and the entire communication device becomes larger due to an increase in the number of components. For this reason, it is difficult to adopt it for a mobile phone or the like, for which a demand for downsizing and price reduction is strong.

Here, an isolator or a circulator is used in communication equipment for the purpose of stable operation and protection of the amplifier. In particular, lumped-constant isolators and circulators function as bandpass filters as their forward characteristics, and therefore have a feature that the attenuation is large even in the forward direction in a frequency band apart from the pass band. It is conceivable to attenuate unnecessary waves by utilizing such characteristics outside the band. However, since the isolator is not originally intended to obtain attenuation outside the band, there is a limit in exhibiting its performance.

Accordingly, the present applicant has proposed an isolator including a circuit element constituting a band-pass filter. In this isolator, as shown in FIG. 11, an inductor L1, which is a component of a band-pass filter, is patterned on a dielectric substrate 18 disposed between the magnetic assembly 4 and the magnet 6, and the inductor L1 is input. It is configured by being added to the port P1.

As shown in an equivalent circuit diagram of FIG. 12, a capacitor C1 which is a component of a bandpass filter is provided.
Is added to the outside of the isolator, and the series capacitor C1 and the series inductor L1 formed on the dielectric substrate 18 have a structure in which a band-pass filter (BPF) is built in the input port P1.

According to the isolator having the above-described band-pass filter, the amount of attenuation outside the frequency band can be increased, and interference and abnormal operation due to unnecessary radiation can be prevented. This makes it possible to form a band-pass filter with a simple structure and at low cost, and to contribute to downsizing and cost reduction of communication equipment by eliminating the need for an expensive amplifier or a separate filter.

[0009]

When the band-pass filter is formed on a dielectric substrate, since a magnet is in contact with the dielectric substrate, high-frequency material characteristics of the magnet, particularly There is a concern that the insertion loss of the isolator is greatly affected by the tangent.

Generally, commercially available magnets that are mass-produced are not developed as high-frequency components, and therefore have a large dielectric loss tangent. Therefore, it is considered that the insertion loss increases due to the contact between the circuit element (inductor) of the dielectric substrate and the magnet. There is also a problem that it is difficult to form an inductor because the magnet has a large dielectric constant.

The present invention has been made in view of such circumstances, and provides a non-reciprocal circuit device capable of reducing insertion loss of an isolator when a circuit device constituting a band-pass filter is formed on a dielectric substrate. It is intended to be.

[0012]

According to the first aspect of the present invention, a magnet is arranged with a dielectric substrate interposed in a magnetic assembly having a plurality of center electrodes crossed on a ferrite, and the magnet is arranged by the magnet. In a non-reciprocal circuit element configured to apply a DC magnetic field to a magnetic assembly, a circuit element constituting a band-pass filter is formed on the dielectric substrate, and at least a circuit element of the dielectric substrate is provided between the magnet and the magnet. It is characterized by sandwiching a dielectric film.

[0013] The invention of claim 2 is characterized in that the dielectric film is adhered to a magnet, and the invention of claim 3 is characterized in that the dielectric film is adhered to a dielectric substrate. Features.

According to a fourth aspect of the present invention, there is provided the same non-reciprocal circuit element as in the first aspect, wherein a circuit element constituting a band-pass filter is formed on the laminated dielectric substrate, and at least the circuit element and the magnet of the laminated dielectric substrate are formed. And at least one layered substrate is provided between them.

According to a fifth aspect of the present invention, there is provided a non-reciprocal circuit device according to the first aspect, wherein a circuit element constituting a band-pass filter is formed on a dielectric substrate, and a dielectric material is formed on at least a part of the surface of the circuit element. It is characterized by being coated with a film.

[0016]

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

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.

The magnetic assembly 4 intersects three center conductors 8, 9, 10 on the upper surface of the disk-shaped ferrite 7 at an angle of 120 degrees with an electric insulating sheet (not shown) interposed therebetween. And the ground portion 11 of each of the center conductors 8 to 10 is in contact with the bottom surface of the ferrite 7.

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, there are formed concave portions 3d for accommodating the single plate type capacitors 12a to 12c for matching and the single plate type terminating resistor R, respectively. 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.

On the outer surfaces of the left and right side walls 3a of the terminal block 3, input / output terminals 15 for surface mounting and ground terminals 16 are provided.
Are formed, and the input / output terminal 15 is led out to a corner on the upper surface of the bottom wall 3b. Also, the ground terminal 1
Numeral 6 is led out to the upper surface of each of the concave portions 3d, and the lower electrodes of the capacitors 12a to 12c and one end of the terminating resistor R are connected. Each of the terminals 15 and 16 is formed by partially insert-molding the terminal block 3.

The input / output ports P1 to P3 of the center 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. The portion 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 dielectric plate 18 having a rectangular plate shape is provided. This dielectric substrate 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 held by the capacitors 12a to 12c, respectively. A hole 18a is formed at the center of the dielectric substrate 18 corresponding to the magnetic assembly 4, and a notch 18b is formed at a corner corresponding to the terminating resistor R.

FIG. 2 shows the upper surface of the dielectric substrate 18.
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 a connection electrode 22 on the back surface, and the other end is also connected via a through-hole electrode 23 to an input electrode 24 on the back surface.

The connection electrode 22 is connected to the capacitor 12a.
And the input electrode 24 is connected to the input port P of the center conductor 8.
1 connected. 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 a bandpass filter (BPF) is formed by the inductor L1 and the capacitor C1 (see an equivalent circuit diagram in FIG. 12).

A dielectric film 25 is provided between the dielectric substrate 18 and the permanent magnet 6, and the dielectric film 25 is sandwiched between the permanent magnet 6 and the dielectric substrate 18. This dielectric film 25 is used for the permanent magnet 6
Is a quadrangular one that covers the entire lower surface, and has a small dielectric constant and a small dielectric tangent.

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 substrate 18 and a band-pass 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 (second harmonic, 3 The amount of attenuation in harmonics 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
Connected to a band-pass filter, the load fluctuation in the output band of the amplifier in the communication equipment can be reduced, the current consumption of the amplifier can be reduced, the operation of the amplifier can be stabilized, and the performance of the communication equipment can be improved. Can contribute. That is, the current consumption of the amplifier is liable to change remarkably due to the load fluctuation of the output section. Therefore, it is necessary to suppress the load fluctuation of the output section within the band as much as possible.

When the inductor L1 is formed on the dielectric substrate 18, the inductor L1
However, there is a concern that the insertion loss of the isolator increases due to the contact of the permanent magnet 6 with the permanent magnet 6. On the other hand, in the present embodiment, since the dielectric film 25 having a small dielectric constant and a small dielectric loss tangent is sandwiched between the dielectric substrate 18 and the permanent magnet 6, the permanent magnet 6 having a large dielectric constant and a large dielectric loss tangent is connected to the inductor. It can be separated from L1, thereby increasing the inductance and reducing the insertion loss, thereby improving the Q of the inductor and consequently reducing the insertion loss of the isolator.

Here, in the present embodiment, the case where the dielectric film 25 has a rectangular shape covering the entire lower surface of the permanent magnet 6 has been described. However, an object of the present invention is to provide a permanent magnet having a large dielectric constant and a large dielectric loss tangent with the inductor. And the dielectric constant between them,
This can be realized by sandwiching a dielectric having a small dielectric loss tangent.
Therefore, the shape and size of the dielectric film are not particularly limited.

For example, since air is also a dielectric having a small dielectric constant and a small dielectric loss tangent, the inductor L of the dielectric film 25
It is also possible to form a hole in a portion in contact with 1 and provide an air layer between the magnet and the inductor by the hole, and in this case, the same effect as in the above embodiment can be obtained. When a dielectric film having holes is used, a film having a large dielectric constant and a large dielectric loss tangent can be used.

FIG. 3 is a characteristic diagram showing measurement results of insertion loss performed for confirming the effect of the lumped constant type isolator. The relative permittivity of the permanent magnet used in this experiment is 25, the dielectric loss tangent is 1 × 10 ⁻² , the relative dielectric constant of the dielectric film is 3.5, the dielectric loss tangent is 2 × 10 ⁻³ , and the thickness is Is 50 μm. For comparison, the same measurement was performed for an isolator without a dielectric film (in the figure, a dashed line indicates a comparative example, and a solid line indicates the present example). As can be seen from the figure, the insertion loss can be improved by about 0.05 dB by using the dielectric film.

In the above embodiment, the inductor L1 is formed at the port P1, but the present invention may be formed at the port P2 or the port P3. Further, in the above embodiment, the series inductor L as a component of the band-pass filter is used.
1 is formed on the dielectric substrate 18 and the other component, the series capacitor C1, is externally described. However, the present invention is not limited to this. Both the inductor and the capacitor are mounted on the dielectric substrate. It may be formed.

FIG. 4 is a view for explaining another embodiment in which both the inductor and the capacitor are formed.
FIG. 4A is a plan view of an inductor formed on a dielectric substrate, and FIG. 4B is a perspective plan view of an electrode formed on the back surface of the dielectric substrate. In the figure, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts.

In the present embodiment, a series inductor L1 as a circuit element constituting a band-pass filter and a first electrode 30a of a series capacitor C1 are formed on the upper surface of a dielectric substrate 18.
Both of the second electrodes 30b are formed by patterning.

One end of the inductor L1 is connected to a matching capacitor 12 through a through-hole electrode 21 and a connection electrode 22.
a. The other end of the inductor L1 is connected to the first electrode 30a of the series capacitor, and the second electrode 30b of the series capacitor opposed to the first electrode 30a with the dielectric substrate 18 interposed therebetween is connected to the input port P via the input electrode 24.
1 connected.

As a result, a bandpass filter including a series inductor L1 and a series capacitor C1 is added to the input port P1 (see the equivalent circuit diagram in FIG. 5).

Also in this embodiment, by inserting a dielectric film between the dielectric substrate 18 and the permanent magnet, the insertion loss of the isolator can be reduced while preventing interference and abnormal operation due to unnecessary radiation. The same effects as in the embodiment can be obtained. Further, since both the inductor L1 and the capacitor electrode C1 are formed on the dielectric substrate 18, the number of components can be reduced and the size can be reduced as compared with a case where either one is externally mounted.

FIG. 6 is an exploded perspective view showing a lumped-constant isolator according to an embodiment of the present invention. In FIG. 6, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

Lumped constant type isolator 1 of this embodiment
Is to sandwich a dielectric film 25 having a small dielectric constant and a small dielectric loss tangent between the dielectric substrate 18 and the permanent magnet 6,
This is an example in which the dielectric film 25 is attached to the lower surface of the permanent magnet 6.

In this embodiment, since the dielectric film 25 is sandwiched between the dielectric substrate 18 and the permanent magnet 6 and adhered to the magnet 6, the effect of reducing the insertion loss of the isolator can be reduced as in the above embodiment. As a result, the dielectric film 25 can be easily assembled when the isolator is assembled, and the workability can be improved.

FIG. 7 is an exploded perspective view showing an embodiment of the third aspect of the present invention, in which the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

Lumped constant type isolator 1 of the present embodiment
Is to sandwich a dielectric film 25 having a small dielectric constant and a small dielectric loss tangent between the dielectric substrate 18 and the permanent magnet 6,
This is an example in which the dielectric film 25 is attached to the entire upper surface of the dielectric substrate 18.

In the present embodiment, since the dielectric film 25 is sandwiched between the dielectric substrate 18 and the permanent magnet 6 and adhered to the magnet 6, the effect of reducing the insertion loss of the isolator can be reduced as in the above embodiment. In addition to the above, the dielectric film 25 can be easily assembled when the isolator is assembled in the same manner as described above, and the workability can be improved.

FIG. 8 is a diagram for explaining a lumped-constant isolator according to the first embodiment of the present invention. In FIG. 8, the same reference numerals as those in FIG. 2 denote the same or corresponding parts.

In this embodiment, an inductor L1, a connection electrode 22, and an input electrode 24 as circuit elements constituting a band-pass filter are formed on both surfaces of a first dielectric substrate 31, and an upper surface of the first dielectric substrate 31 is formed. And a single layer of the second dielectric substrate 32 on which nothing is formed.

According to this embodiment, since the second dielectric substrate 32 is laminated on the first dielectric substrate 31 on which the inductor L1 is formed, the insertion loss of the isolator can be reduced, and the same effect as in the above embodiment can be obtained. can get. Further, the first and second dielectric substrates 31 and 32 can be integrally formed by laminating them,
The number of parts can be reduced as compared with the case where the above-described dielectric film is used, and the cost can be further reduced.

FIG. 9 is a view for explaining a second embodiment of the invention of claim 4, in which the same reference numerals as those in FIG. 8 denote the same or corresponding parts.

In this embodiment, the inductor L1 is formed on the upper surface of the first dielectric substrate 31 by patterning, and the second dielectric substrate 3
Connection electrode 2 connected to the inductor L1
2 is an example in which the input electrode 24 is formed in a pattern.

In this embodiment, the first and second dielectric substrates 3
The inductor L1 and the connection electrode 2
2. Since the input electrodes 24 are formed, the manufacturing is easier, the cost can be further reduced, and an inexpensive and low-loss isolator can be provided as compared with the case where the electrodes are patterned on both surfaces of one substrate.

FIG. 10 is a diagram for explaining an embodiment of the invention of claim 5, in which the same reference numerals as in FIG. 2 indicate the same or corresponding parts.

In this embodiment, the inductor L1 on the upper surface of the dielectric substrate 18 is coated with a thick dielectric film 35 by printing or the like. The dielectric film 35 covers the entire length of the inductor L1 excluding the line central portion 36, and the central portion 36 is an air layer formed between the dielectric film 35 and the magnet.

In this embodiment, since the dielectric film 35 having a small dielectric constant and a small dielectric loss tangent is applied to the inductor L1 of the dielectric substrate 18, the insertion loss of the isolator can be reduced, and the same effect as the above embodiment can be obtained. Can be In addition, since the structure is such that the dielectric film 35 is applied to the dielectric substrate 18, it is possible to avoid an increase in the number of components which causes an increase in cost and to provide the device at low cost.

Since the central portion 36 of the inductor L1 is covered with a dielectric layer made of air, the dielectric film 3
The same operation and effect as in the case of applying No. 5 can be obtained. In this case, the dielectric film may be covered over the entire length without exposing the central portion 35.

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.

[0055]

As described above, according to the non-reciprocal circuit device according to the first aspect of the present invention, the circuit element constituting the band-pass filter is formed on the dielectric substrate, and the circuit element on the dielectric substrate, the magnet and Since the dielectric film is interposed between the magnets, the magnet having a large dielectric constant and a large dielectric tangent can be separated from the circuit element, and the insertion loss of the isolator can be reduced.

Further, since the low-pass filter can be configured with a simple structure and at low cost, it is possible to contribute to miniaturization and cost reduction while avoiding interference and abnormal operation due to unnecessary radiation.

According to the second aspect of the present invention, the dielectric film is attached to a magnet, and in the third aspect of the invention, the dielectric film is attached to a dielectric substrate. The effect of reducing the loss is obtained, and the dielectric film can be easily incorporated at the time of assembling the isolator, thereby improving the workability.

According to the fourth aspect of the present invention, since at least one layered substrate is provided between the circuit element of the laminated dielectric substrate and the magnet, the effect of reducing the insertion loss of the isolator can be obtained as in the first aspect. At the same time, it is possible to avoid an increase in the number of components that causes an increase in cost, and to provide an inexpensive product.

According to the fifth aspect of the present invention, at least a part of the surface of the circuit element of the dielectric substrate is covered with the dielectric film.
As in the first aspect, the effect of reducing the insertion loss of the isolator can be obtained, and an increase in the number of components that causes an increase in cost can be avoided, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view for explaining a lumped constant type isolator according to an embodiment of the present invention.

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

FIG. 3 is a characteristic diagram showing an effect of the embodiment.

FIG. 4 is a view showing a dielectric substrate according to another embodiment of the above embodiment.

FIG. 5 is an equivalent circuit diagram of the isolator to which the band pass filter of the embodiment is added.

FIG. 6 is an exploded perspective view showing a lumped-constant isolator according to an embodiment of the present invention.

FIG. 7 is an exploded perspective view showing a lumped-constant isolator according to an embodiment of the third invention.

FIG. 8 is an exploded perspective view of the dielectric substrate according to the first embodiment of the present invention.

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

FIG. 10 is a view showing a dielectric substrate according to an embodiment of the present invention.

FIG. 11 is an exploded perspective view of an isolator for explaining a process of establishing the present invention.

FIG. 12 is an equivalent circuit diagram of the 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 substrate 20 Circuit element 25 Dielectric film 31 First dielectric substrate 32 Second dielectric substrate 35 Dielectric Body film L1 Inductor (circuit element) C1 Capacitor (circuit element)

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

Claims (5)

[Claims] A magnet is disposed with a dielectric substrate interposed in a magnetic assembly having a plurality of center electrodes crossed on a ferrite, and a DC magnetic field is applied to the magnetic assembly by the magnet. In the non-reciprocal circuit device, a circuit element constituting a band-pass filter is formed on the dielectric substrate, and a dielectric film is sandwiched between at least the circuit element and the magnet of the dielectric substrate. Non-reciprocal circuit element. 2. The non-reciprocal circuit device according to claim 1, wherein the dielectric film is adhered to a magnet. 3. The non-reciprocal circuit device according to claim 1, wherein the dielectric film is adhered to a dielectric substrate. 4. A magnet in which a laminated dielectric substrate is interposed in a magnetic assembly having a plurality of center electrodes intersected with ferrite and a DC magnetic field is applied to the magnetic assembly by the magnet. In the non-reciprocal circuit device, a circuit device constituting a bandpass filter is formed on the laminated dielectric substrate, and at least one laminated substrate is provided between at least the circuit device and the magnet of the laminated dielectric substrate. A non-reciprocal circuit device. 5. A magnet in which a dielectric substrate is interposed in a magnetic assembly comprising a plurality of center electrodes intersecting a ferrite and a DC magnetic field is applied to the magnetic assembly by the magnet. A non-reciprocal circuit device according to claim 1, wherein a circuit device constituting a band-pass filter is formed on the dielectric substrate, and at least a part of the surface of the circuit device is covered with a dielectric film.