JPH0246083Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a non-reciprocal circuit element used as an isolator or circulator in the microwave region. By arranging permanent magnets with concave surfaces facing each other, the direct current magnetic field of the permanent magnets is applied uniformly to the surface of the magnetic material,
This is designed to reduce passing loss and improve microwave transmission efficiency.

<Prior Art> As non-reciprocal circuit elements, lumped constant type and distributed constant type are well known. Among these, the lumped constant type nonreciprocal circuit elements are arranged at an angle of about 120 degrees to each other, as shown in FIGS. 8 and 9.
While arranging three strip conductors 1 to 3,
Magnetic materials 4, 5 such as garnet or ferrite are placed on both sides of the magnetic materials 4, 5, and permanent magnets 6, 7 are placed facing each other on the outside of the magnetic materials 4, 5. A DC magnetic field is applied approximately perpendicularly to the magnetic field. The permanent magnets 6 and 7 have opposing surfaces 61 and 71 facing the magnetic bodies 4 and 5 formed into a larger planar shape than the opposing surfaces 41 and 51 of the magnetic bodies 4 and 5, and the opposite surfaces 41 and 71 of the magnetic bodies 4 and 5 , 51 are arranged facing each other so as to cover them. Further, the strip conductors 1 to 3, the magnetic bodies 4 and 5, and the permanent magnets 6 and 7 are arranged inside a case 8 so as to be shielded from the outside.

Next, as shown in FIGS. 10 and 11, the distributed constant type non-reciprocal circuit element is constructed by placing a Y-junction strip conductor 10 on one surface of the flat magnetic body 9.
In addition, permanent magnets 6 and 7 are arranged facing each other on both sides of the magnetic body 9, and the entire structure is housed in a case 8. On the outer periphery of the strip conductor 10, strip terminal conductors 101 to 103 are arranged.
Circuit components 14 to 16 for impedance adjustment are arranged in three equal parts at an angle of 120 degrees and are connected to conductors 11 to 13 formed near the end of the magnetic body 9.
is connected.

<Problems to be solved by the invention> However, in conventional non-reciprocal circuit elements,
In both the lumped constant type and the distributed constant type, the permanent magnets 6 and 7 have a surface side 6 facing the magnetic bodies 4, 5, and 9.
1 and 71 are flat planes, a large amount of magnetic flux leaks to the outside at the outer periphery of the permanent magnets 6 and 7, and the DC magnetic field applied to the magnetic bodies 4, 5, and 9 is uneven between the inside and outside. There was a problem that the microwave transmission loss increased and the transmission efficiency decreased.

<Means for Solving the Problems> In order to solve the above-mentioned conventional problems, the non-reciprocal circuit element according to the present invention has an opposite surface on at least one side of a magnetic body on which a strip conductor is arranged. It is characterized by having concave permanent magnets arranged facing each other.

<Function> When the opposing surface of the permanent magnet is made concave, the distance from the opposing surface of the permanent magnet to the opposing surface of the magnetic material becomes shorter as it goes closer to the outer periphery of the permanent magnet, and leakage from the outer periphery of the permanent magnet to the outside becomes smaller. Since the magnetic flux is reduced, a uniform DC magnetic field is formed over the entire surface of the magnetic body, reducing passing loss and improving microwave transmission efficiency.

<Example> FIG. 1 is a partial cross-sectional view of a lumped constant type nonreciprocal circuit element according to the present invention. In the figure, the same reference numerals as in FIGS. 8 and 9 indicate the same components. In this embodiment, the opposing surface of the permanent magnet 6 that faces the magnetic body 4 is a spherical concave surface 61. Therefore, the closer to the outer periphery of the permanent magnet 6, the shorter the distance from the concave surface 61 of the permanent magnet 6 to the facing surface 41 of the magnetic body 4 becomes, and the less magnetic flux leaks from the outer periphery of the permanent magnet 6 to the outside. , a uniform DC magnetic field is formed over the entire surface of the magnetic body 4,
Microwave passage loss is reduced. Furthermore, since this embodiment uses one permanent magnet 6, it is smaller and cheaper than the conventional one using two permanent magnets.

FIG. 2 shows an embodiment in which the present invention is applied to a distributed constant type irreciprocal circuit element. In the figure, the first
The same reference numerals as in FIGS. 0 and 11 indicate the same components, and the permanent magnet 6 facing the magnetic body 9
The opposing surface is a curved concave surface 61. In this embodiment as well, the same effects as in the embodiment of FIG. 1 can be obtained.

As the shape of the concave surface 61 of the permanent magnet 6, a stepped concave surface as shown in FIGS. 3 and 4, a conical concave surface as shown in FIG. 5, etc. are also suitable. Similar effects can be obtained in this case.

Furthermore, in the case of the embodiments shown in FIGS. 3 and 4, the outer circumference of the concave surface 61 is formed into a ring-shaped flat surface 62 having a width W1.
Therefore, permanent magnet 6 made of ferrite etc.
The advantages include that chipping is less likely to occur on the outer periphery of the magnet, stable characteristics can be obtained, the magnetic field on the outer periphery becomes more uniform, passing loss is reduced, and efficiency is improved.

6 and 7, based on the teachings of FIGS. 3 and 4, the permanent magnet 6 shown in FIGS. 1, 2, and 5 is An embodiment is shown in which a ring-shaped flat surface 62 with a width W ₁ is provided.

<Effects of the Invention> As described above, the irreversible circuit element according to the present invention has a permanent magnet having a concave opposing surface disposed facing at least one surface of a magnetic material on which a strip conductor is arranged. Because of these characteristics, it is possible to provide a non-reciprocal circuit element in which the DC magnetic field of a permanent magnet acts uniformly on the surface of a magnetic material, thereby reducing passage loss and improving microwave transmission efficiency.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a lumped constant type non-reciprocal circuit element according to the present invention, FIG. 2 is a partial cross-sectional view of a distributed constant type non-reciprocal circuit element, and FIG. FIG. 4 is a cross-sectional view of another embodiment of the permanent magnet used, FIG. 5 is a cross-sectional view of yet another embodiment, and FIGS. 6 and 7 are from this book. 8 is an exploded perspective view of a conventional lumped constant type non-reciprocal circuit element, and FIG. 9 is a partial cross-section thereof. 10 is a plan view of a main part of a conventional distributed constant type nonreciprocal circuit element, and FIG. 11 is a partial sectional view thereof. 1 to 3, 10... Strip conductor, 4, 5, 9
... Magnetic material, 6,7 ... Permanent magnet, 61 ... Opposing surface (concave surface).

Claims (1)

[Claims for Utility Model Registration] (1) A non-reciprocal circuit element characterized in that a permanent magnet having a concave opposing surface is disposed facing at least one side of a magnetic body on which a strip conductor is arranged. (2) The non-reciprocal circuit element according to claim 1, wherein the opposing surface is a curved concave surface. (3) The non-reciprocal circuit element according to claim 1, wherein the opposing surface is a stepped concave surface. (4) The non-reciprocal circuit element according to claim 1, wherein the opposing surface is a concave conical surface. (5) The opposing surface is characterized in that the periphery of the concave surface is a ring-shaped flat surface. non-reciprocal circuit element.