JPS6221045Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultra-high frequency isolator, and particularly to a magnetic resonance isolator.

A particularly small, lightweight, and low-cost isolator is required for use in civilian communication broadcasting equipment in the ultra-high frequency band, especially the UHF band. An isolator using a conventional lumped constant circulator is
In particular, the structure is complicated, and there are limits to how low the price can be reduced. The authors have already proposed a magnetic resonance type lumped constant isolator, as shown in Figure 1, as an alternative to this, with a simpler structure, fewer components, and lower costs.

Figure 1 shows the structure of a magnetic resonance type lumped constant isolator, in which a is a perspective view of the top cover that forms part of the magnetic circuit, b is a perspective view of the main circuit, and c is a combination of a and b. FIG.

In FIG. 1, a dielectric substrate 1 on which a circuit pattern is formed on the surface of a magnetic metal plate 10 that also serves as a ground conductor is fixed with a ground conductor 3 in contact with the dielectric substrate 1. A bonding electrode 4 is fixedly arranged on the surfaces of the magnetic plates 2 and 3, and a lumped constant capacitor 120 and a lumped constant inductor formed of the dielectric substrate 1 are respectively formed in two opposing openings of the four orthogonal openings of the bonding electrode 4. 130
are connected to load negative and positive reactance circuits, respectively, and an input/output impedance conversion circuit consisting of a series lumped inductor 140 and a parallel lumped capacitor 150 is connected to the remaining two opposing openings, and the input/output terminals It is connected to 200. Furthermore, an upper lid 5 made of magnetic metal with a permanent magnet 50 attached to the lower side
1 is placed over the top and fixed in the set screw hole 101 with a set screw 101', thereby forming a magnetic circuit section that magnetizes the ferrimagnetic plate 2 in a magnetic resonance magnetic field and serves as a cover together with the magnetic metal plate 10. At the same time, a miniature isolator with mounting holes 102, 102' is constructed. The equivalent circuit of this isolator is shown in FIG.

The characteristics of such an isolator vary depending on the material and dimensions of the ferrimagnetic plate used, circuit constants, environmental temperature, signal power, magnetic circuit structure and dimensions, etc., and determine the operating frequency band characteristics. It was found that there was an isolator with characteristics as shown by the dotted line A in FIG. 3 among them.

As can be seen from the figure, the forward loss is not necessarily small enough and is sloped with respect to the frequency, so the frequency at which the reverse loss is maximum is different from the frequency at which the forward loss is minimum. This results in
Operating frequency and band are limited. The deterioration of such characteristics increases the reverse direction loss of the isolator, so the larger and thicker the ferrimagnetic plate, the smaller the isolator dimensions with the same characteristics, the smaller the permanent magnet, and the larger the permanent magnet. This becomes more noticeable as the distance between the magnet and the ferrimagnetic material becomes narrower. Therefore, this is considered to be a major practical problem.

The purpose of the present invention is to improve the above problems and provide a practical isolator.

According to the present invention, a ferrimagnetic material is placed on a ground conductor, and a bonding electrode having four openings spaced apart at an angle of 90 degrees from each other is placed on the top surface of the ferrimagnetic material, and a positive and negative reactance circuit is connected to each of the two opposing openings. In the isolator, the isolator has a magnetic circuit for applying a load, connecting the remaining two openings to an input/output circuit, and further magnetizing the ferrimagnetic plate perpendicularly to the surface. An isolator is obtained which is characterized by having holes of.

Next, the present invention will be explained using the drawings.

First, when measuring the magnetic field distribution in the space between the permanent magnet, the magnetic metal plate, and the ferrimagnetic plate for an isolator that exhibits the characteristics shown by the dotted line A in Figure 3, the distribution as shown by the dotted line A in Figure 4 is obvious. It became. The dimensions of the ferrimagnetic plate used here were 8 mm in diameter and 1 mm in thickness. As can be seen from the figure, the magnetic field swells in a portion corresponding to the diameter of the ferrimagnetic material. It is thought that such non-uniform magnetic field distribution is caused by the fact that the ferrimagnetic plate 2 is placed on the planar magnetic metal plate 10, as shown in FIG. 1c. That is, the strength of the magnetic field is determined by the magnetic resistance applied to the magnetic flux generated by the permanent magnet. The magnetic resistance of the magnetic metal plate and the top cover is extremely low compared to the space, so the strength of the magnetic field is mainly determined by the facing distance between the permanent magnet and the magnetic metal plate facing it, but ferrimagnetism The magnetic permeability of the body to a DC magnetic field is between that of air and that of magnetic metals, and is rather close to that of magnetic metals. Therefore, the strength of the magnetic field in this portion becomes non-uniform by an amount corresponding to the thickness of the ferrimagnetic plate.

In the present invention, a hole is formed in the magnetic metal plate 10 in a shape that corresponds to the shape of the ferrimagnetic material plate, a uniformly distributed magnetic field is generated, and this is applied to the ferrimagnetic material, thereby improving the conventional characteristics. It measures the

FIG. 5 is a sectional view corresponding to FIG. 1c showing an embodiment of the present invention. Perspective views of the present invention are shown in Figures 1a and b.
is exactly equivalent to . Also, since the constituent elements are the same, the same numbers are used. Unlike FIG. 1c, in this embodiment, as can be seen from FIG. It is. depth t
is preferably a value obtained by multiplying the ratio of the DC magnetic field permeability of the ferrimagnetic plate 2 to the magnetic permeability of the magnetic metal plate 10 by the thickness of the ferrimagnetic plate.

In experiments in which the characteristics shown in Figs. 3 and 4 were actually obtained, the ferrimagnetic plate 2 was
When the magnetic field was lowered by 0.5 mm, the magnetic field distribution became almost flat as shown by the solid line B in FIG. 4, and the isolator characteristics at that time became as shown by the solid line B in FIG. 3. In other words, compared to characteristic A before improvement, the insertion loss is reduced while the reverse direction loss is almost constant, and is also significantly flattened with respect to frequency, and its center frequency is also the same as the center frequency of the reverse direction loss. Match. Therefore, it can be seen that the operating band that satisfies a certain reference value is also very wide, and is very effective in practice.

In this embodiment, the Koeri magnetic plate 2 is
Although Ca-V garnet is used, ordinary microwave ferrites such as YIG ferrite can also be used. Further, although gold-plated pure iron was used as the magnetic metal plate, it goes without saying that other soft iron and steel materials with various surface finishes may be used. Further, although alumina was used as the dielectric substrate, it goes without saying that other materials such as Teflon (registered trademark) glass-based printed boards and others may be used.

In this isolator, reverse direction loss power is directly absorbed by the ferrimagnetic plate 2, so this heat dissipation is important, especially in the case of large power. By embedding the ferrimagnetic plate 2 in the magnetic metal plate 10 and filling the gap with a conductor, dielectric material, etc. with good thermal conductivity, a secondary effect of improving heat dissipation will also be produced.

In this embodiment, the depth t of the hole in the magnetic metal plate 10 is approximately half the thickness of the ferrimagnetic plate 2, but due to the value of magnetic permeability described above, t
It is conceivable that the thickness is the same as or even greater than the thickness of the ferrimagnetic plate. In that case, the difference in level between the surface of the bonding electrode 4 and the dielectric substrate 1 becomes large, and an extra parasitic element is generated when inputting a signal to the ferrimagnetic plate, making it necessary to adjust the circuit.

As an embodiment that avoids this problem, a second embodiment is shown in FIG. 6 as a sectional view of the vicinity of the joint. In this embodiment, a hole is formed in the center of the magnetic metal plate 10 in a shape corresponding to the shape of the ferrimagnetic plate 2 and with a depth comparable to the thickness of the ferrimagnetic plate 2, and the entire hole is covered with the non-magnetic plate 5.
The ferrimagnetic plate 2 is placed on top of the ferrimagnetic plate 2. This makes it possible to avoid the above-mentioned structural problems and to improve the magnetic field distribution according to the present invention.

The nonmagnetic plate 5 is made of ordinary copper, gold, aluminum, or the like. In particular, the use of copper is more advantageous in terms of heat dissipation.Also, a dielectric plate having a conductive film formed on its surface may be used, and the conductive film may be connected to a magnetic metal plate. Furthermore, even if it is filled with a simple dielectric material that does not form a conductive film on the surface, a good isolator can be formed if the circuit is designed using the composite of the ferrimagnetic plate 2 and the dielectric material as the joint part of this isolator. can. Such an isolator has already been proposed by the authors, and in such an isolator, the series inductor 140 and parallel capacitor 150 shown in FIG. 1 or FIG.
The input/output impedance conversion circuit consisting of the above can be eliminated.

As another embodiment of such an isolator, a third embodiment is shown in FIG. 7, which is also a sectional view of the vicinity of the joint. In this embodiment, magnetic metal plate 1
The ferrimagnetic plate 2 is completely embedded in 0,
A dielectric substrate 1 on which a parallel capacitor 120 or a parallel inductor 130 for excitation of a circuit magnetic field is formed.
The bonding electrode 4 is formed on the dielectric substrate as a conductive pattern continuous with the circuit element. With such a structure, an input/output impedance converter is usually unnecessary, a simple circuit configuration is possible, and good isolator characteristics due to a uniform magnetic field can be obtained.

In all of the previous examples, flat magnets were used as shown in FIG. However, even if the opposing magnetic circuits are made magnetically uniform, it is not possible to prevent magnetic flux from leaking into the air.In order to apply a sufficiently uniform magnetic field to the ferrimagnetic plate, the magnet dimensions must be adjusted to the ferrimagnetic plate size. It has to be much larger. As a result, even though this isolator can be significantly miniaturized in terms of circuitry, the final dimensions are limited by the permanent stone.

FIG. 8 shows a fourth embodiment of the present invention in a sectional view corresponding to FIG. 1c. Components that are the same as those in FIG. 1 are indicated using the same numbers.

In this embodiment, unlike the previous embodiments, the ferrimagnetic plate 2 is placed as it is on the flat magnetic metal plate 10, and in order to supply a uniform magnetic field, a central portion is placed under the permanent magnet 50. A disk or ring-shaped magnetic field correction magnetic plate 52 having a generally circular hole corresponding to the shape of the ferrimagnetic plate 2 is attached to the ferrimagnetic plate 2 . With this magnetic substrate 52, correction corresponding to the magnetic field increasing effect of the ferrimagnetic plate 2 itself can be made in other parts, especially for the magnetic flux at the wire end of the permanent magnet, and the isolator characteristics described so far can be made. improvement can be measured.

FIG. 9 is a sectional view showing a fifth embodiment of the present invention. In this case, a magnetic field correction magnetic plate 52 similar to the embodiment shown in FIG. 4 is inserted between the permanent stone 50 and the upper cover 51 which also serves as a magnetic circuit. As the magnetic plate 52, the same magnetic metal as the upper cover 51, such as pure iron or soft iron, or a ferrimagnetic material, or if necessary, a permanent magnetic material itself can be used.

The present invention has been described above using examples, and the isolator circuit is similar to that shown in FIG. 1, which has already been proposed. However, in the present invention, the series inductor 140 and the parallel capacitor 1 in FIG.
Needless to say, the present invention can be applied to a case where it is not necessary to use an impedance conversion circuit consisting of 30 circuit elements, or to a case where all circuit elements are of a distributed constant type consisting of strip lines. It is also natural that the effects of the present invention can be achieved by various combinations of the previous embodiments. Needless to say, the shapes of the holes in the ferrimagnetic plate and the corresponding magnetic metal plate are not limited to circular shapes.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional isolator proposed by the same applicant, in which a and b are perspective views of the upper lid and the main circuit, respectively, and c is a sectional view taken along the line A-A'. FIG. 2 is this equivalent circuit diagram. FIG. 3 and FIG. 4 are a characteristic diagram and a magnetic field distribution diagram, respectively, comparing the conventional device and the present invention. In the figure, 1...dielectric substrate, 2...ferrimagnetic plate, 3...ground conductor, 4...junction electrode, 10
... Magnetic metal plate, 120 ... Lumped constant capacitor, 130 ... Lumped constant inductor, 140 ...
Series lumped constant inductor, 150... lumped constant capacitor, 200... input/output terminal, 31... short circuit conductor, 101... mounting hole, 102... mounting hole, 101'... mounting screw, 150... permanent magnet, 51... Upper lid. Fig. 5 shows the first embodiment of the present invention, and is a sectional view corresponding to Fig. 1c, and Figs. 6 and 7 correspond to the joints in Fig. 5 of the second and third embodiments. This is a cross-sectional view of only a portion, and all the component numbers used are exactly the same as in FIG. 1. In addition, 5 is a non-magnetic plate. 8 and 9 are cross-sectional views corresponding to FIG. 1c showing the fourth and fifth embodiments of the present invention,
The same components were used in both cases. In addition, 52 is a magnetic plate for magnetic field correction.

Claims (1)

[Scope of utility model registration request] A ferrimagnetic plate is placed on the ground conductor, and a bonding electrode having four openings spaced apart at 90 degrees from each other is placed on the top surface of the plate. Positive and negative reactance circuits are loaded to each of the two opposing openings, and the remaining In an isolator having a magnetic circuit that connects two openings to an input/output circuit and further magnetizes the ferrimagnetic plate perpendicular to the surface, the ferrimagnetic plate is placed at a position facing the ferrimagnetic plate of the magnetic member in the magnetic circuit. An isolator characterized by having a hole with a shape similar to that of a ferrimagnetic material.