JPH0227601Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to non-reciprocal circuit elements such as isolators and circulators used in high frequency ranges such as microwaves. Use a yoke that does not cover the housing, expose a part of the housing, and form a mounting screw hole there.
This invention relates to a non-reciprocal circuit element whose casing can be directly connected to earth.

[Prior Art] Hereinafter, a circulator type isolator will be described as an example of a non-reciprocal circuit element.

There are various structures for isolators used in high frequency areas such as microwaves. One of them uses a circulator, connects a dummy load to one terminal of the circulator, and terminates it without reflection. There is a circulator-type isolator that absorbs energy and exhibits isolator characteristics.

For example, as shown in FIG. 3, this type of isolator is constructed by disposing ferrite plates 12 and 14 on both sides of an inner conductor 10 having three terminals, and sandwiching the plates between casings 16 and 18 from both sides. In this structure, one terminal of 10 is soldered and connected to a chip resistor 24 housed and fixed in the inner recessed part of the dummy load mounting plate 22.

As shown in FIG. 4, permanent magnets 26 and 28 are attached to the recessed portions 20 on the outside of the casings 16 and 18 for applying a DC magnetic field therein.
U-shaped yoke 3 to cover the outside of 6 and 18
0 is fixed with adhesive.

[Problems to be solved by the invention] Such an isolator has a U-shaped yoke 3
As shown in FIG. It can be attached by screwing a screw 38 through a through hole 36 of a case 34 of an external device such as the like.

Since the casings 16, 18 and the U-shaped yoke 30 are fixed with adhesive as described above, the adhesive layer 40 is necessarily interposed between them. Therefore, when the case 34 of the external device and the isolator are screwed together,
Although the case 34 is in contact with the U-shaped yoke 30, since there is an adhesive layer 40 between the U-shaped yoke 30 and the housing 18, there is no electrical conduction with the housing 18 just by placing the case 34 thereon. Therefore, the mounting screw 3
The casings 16, 18 and the case 34 are electrically connected only by the terminal 8. For this reason, the grounding of the isolator tends to be incomplete, resulting in unstable characteristics and high insertion loss.

The purpose of the present invention is to eliminate the drawbacks of the conventional technology as described above, and to ensure continuity between the casing and external equipment through surface contact, thereby ensuring complete grounding, stabilizing characteristics, and reducing insertion loss. It is an object of the present invention to provide an improved nonreciprocal circuit element that can reduce the loss of energy.

[Means for Solving the Problems] The present invention, which can achieve the above-mentioned objects, has a structure in which at least one yoke plate of the U-shaped yoke has a small area so that a part of the casing is exposed. A recess of a size and depth that allows the small-area yoke plate to be embedded is formed on the outer surface of the casing, the yoke plate is mounted in the recess, and a plurality of screw holes for mounting are formed in the exposed part of the casing. This is a non-reciprocal circuit element with a structure provided with.

Irreciprocal circuit elements include isolators and circulators.

Preferably, the U-shaped yoke has a structure in which only the case side of the external device has a small area, and the other side has the same size as the casing and completely covers it. The small area yoke plate is preferably located at the center of the outer surface of the casing, and a U-shaped casing exposed portion is formed around the yoke plate, and approximately three to four mounting screw holes are formed therein.

[Function] If you use the mounting screw holes to attach it to the case of a radio device, etc., the case and the case come into direct contact with each other, so even though there is a U-shaped yoke, the case does not touch the case. Can be connected directly to earth.

As a result, the grounding becomes complete and the characteristics of the circuit elements are greatly stabilized.

[Embodiment] Fig. 1 is an exploded perspective view showing an embodiment in which the present invention is applied to an isolator, and Fig. 2 is a partial sectional view after assembly. The structure of the isolator main body may be the same as that of the prior art, so to simplify the explanation, corresponding parts will be given the same reference numerals and their description will be omitted.

The present invention is significantly different from the prior art in the structure of the outer surface of one casing 18 and the U-shaped yoke 3.
0 shape. That is, in the present invention, the two opposing yoke plates 30a of the U-shaped yoke 30,
One of the yoke plates 30a of the yoke plates 30b has the same area as the housing 16 so as to cover it, whereas the other yoke plate 30b has a smaller area. The small-area yoke plate 30 is exactly attached to the housing 18 to which it is attached.
A recess 42 of such a size and depth that b is buried therein is formed. Therefore, the depth of this recess 42 is set to be greater than the thickness of the yoke plate 30b. Three mounting screw holes 32 are formed at positions away from the mounting portion of the small-area yoke plate 30b.

After the permanent magnets 26 and 28 are installed in the recesses 20 formed on the outside of the casings 16 and 18, the U-shaped yoke 36 is attached using adhesive. Therefore, the small-area yoke plate 30b also completely covers the permanent magnet 28. U-shaped yoke 30
closes the magnetic field generated by the permanent magnets 26 and 28 located on both sides to the outside, thereby preventing leakage of magnetic flux and concentrating the magnetic field inside.

As shown in FIG. 2, such an isolator is mounted by placing the U-shaped exposed surface in contact with the case 34 of the external device and screwing the screw 38 into the screw hole 32. As described above, the depth of the recess 40 formed in the housing 18 is the same as or deeper than the thickness of the yoke plate 30b, so the exposed surface of the housing 18 comes into pressure contact with the case 34 of the external device, etc. In combination with the electrical connection provided by the internal screw 38, complete grounding of the isolator is achieved.

An embodiment of the present invention has been described above in detail using an isolator as an example, but it goes without saying that the present invention can also be applied to a circulator having a structure similar to other two-terminals without providing a dummy load section. .

[Effects of the invention] As described above, in the present invention, at least one yoke plate of the U-shaped yokes covering both housings has a small area and is embedded in the housing, so that It makes surface contact with the case of the external equipment to be attached, allowing direct and complete ground contact.

As a result, the characteristics of circuit elements are significantly stabilized,
In addition, the insertion loss is also reduced and reliability can be significantly improved, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention;
Fig. 2 is a partial sectional view showing how it is attached to an external device case, Fig. 3 is an exploded perspective view showing an example of the conventional technology, and Fig. 4 is a partial sectional view showing how it is attached to an external device case. be. 16, 18...Housing, 30...U-shaped yoke, 32...Screw hole for mounting, 40...Recess.

Claims (1)

[Scope of utility model registration request] In a non-reciprocal circuit element in which ferrite plates are arranged on both sides of an inner conductor having three terminals and sandwiched between a casing, a permanent magnet is attached to the outside of the casing, and the ferrite plate is covered with a U-shaped yoke. At least one yoke plate of the letter-shaped yoke has a small area so that a part of the casing is exposed, and a recess of a size and depth is formed on the outer surface of the casing to allow the small-area yoke plate to be embedded. , a non-reciprocal circuit element with multiple mounting screw holes in the exposed part of the casing.