JPS645482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in small, low-cost, and high-performance circulators and isolators used in the VHF, UHF, and microwave bands.

[Conventional technology]

Circulator isolators are the most important components of microwave equipment, and are used in a wide range of microwave fields for purposes such as protecting transistors during high-power operation, matching between stages, and eliminating unnecessary radiation. With the recent dramatic downsizing of other microwave elements, the space occupied by circulators and isolators in the overall microwave apparatus has become quite noticeable. For example, in some types of equipment, it is not uncommon for these space factors to exceed 50%.

Furthermore, in terms of the overall cost of the microwave device, the price of the circulator and isolator has become a significant factor. Therefore, demands for smaller size and lower cost of circulators and isolators are becoming stronger day by day. The present invention aims to reduce the size of the industry,
Circulator to meet the demand for lower prices
This paper relates to structural improvements to isolators.

In general, the structure of a conventional circulator isolator is as shown in Fig. 1, in which two permanent magnets 3a and 3b are placed one above the other in a case 1 that serves as both a magnetic circuit and an electrical shield. A ferrite core 6 and a center conductor 7 are surrounded by a shield plate 5 and placed on a grounding stand 4 in a space exactly in the center of the mounting. Here, 9 is a matching capacitor, and 8 is a stripline terminal for connection to an external circuit. 10 is a printed board for holding the stripline terminal 8. Also,
The upper permanent magnet 3b has an elegant structure in which it can be moved vertically by a rotating screw 2 to finely adjust the magnetic field applied to the ferrite core 6.

Further, the circulator/isolator is used by attaching the case 1 to the heat sink 20 with screws or the like. The heat sources of the circulator/isolator are the ferrite core 6, the capacitor 9, etc., and therefore, in the conventional structure, the heat radiation path is transmitted to the case 1 and the heat sink 20 through the ground stand 4.

However, since the contact area between the ground stand 4 and the case 1 cannot be made large due to the structure, the heat dissipation is not very good. In addition, some of the heat remained in the space between the shield plate 5 and the upper permanent magnet 3b.

In response to this problem, the present inventors have already invented a thin lumped constant type circulator and isolator having an extremely simple structure as shown in FIG.

In this structure, a ferrite core 6 housed in a shield plate 5 is disposed on a soft magnetic material 12 that functions as a ground conductor, and another soft magnetic material 11 is placed on top of the ferrite core 6. Permanent magnets 3 are placed closely together. Around the ferrite core 6, a matching capacitor 9 and a stripline terminal 8 are provided as in FIG.

The structure shown in Figure 2 has a significantly fewer number of parts than the one shown in Figure 1, as it requires only one permanent magnet and does not require a magnetic shield case, and at the same time has a high circulator and isolator. It had various advantages such as being extremely thin.

Also, since the heat radiation path is transmitted to the heat sink 20 through the shield plate 5, the distance between the heat source and the heat sink 20 is shorter than that in FIG. 1, and the heat path area is wider.
Heat dissipation was also significantly improved compared to the conventional model.

[Problem that the invention seeks to solve]

However, in the structure shown in Figure 2, the circulator
When installing the isolator, the worker may accidentally come into contact with a capacitor, etc. and deteriorate the characteristics of the circulator/isolator, or the permanent magnet 3 may attract iron parts or dust because it is exposed. There were other problems.

In addition, with conventional circulators and isolators, the heat generated inside the circulator/isolator has a structure in which the heat dissipation path passes through the grounding stand, resulting in poor heat dissipation. Since there is an air space between the magnet and the magnet, the disadvantage is that heat tends to accumulate in that space.

In view of the above, an object of the present invention is to improve operational problems and realize a lumped constant circulator and isolator with high heat dissipation effects.

[Means for solving problems]

In order to achieve the above object, the present invention applies a DC magnetic field to one or more ferrite cores, and as a method for applying the DC magnetic field, arranges the ferrite core between two or more soft magnetic bodies, A permanent magnet is arranged from the outside of either one of the soft magnetic bodies, and one end of each of the three or more central conductors that are in close contact with the ferrite core is exposed outside the circulator and isolator, and is directly connected to the external circuit. In lumped constant circulators and isolators that serve as stripline terminals for connection, among the two or more soft magnetic materials,
A non-magnetic metal case whose ends are in contact with the soft magnetic material placed below and serving as a ground conductor is covered, and a portion of or all of the gap between the inner surface of the case and the permanent magnet is filled with 5×10 ^- It is characterized by being filled with a filler that has a thermal conductivity of ⁴ cal/cm・sec・℃ or higher.

〔Example〕

Hereinafter, the present invention will be explained in detail using examples.

FIG. 3 is a perspective view of each component showing one embodiment of the present invention. That is, the shield plate 15 is placed on the soft magnetic material 12 that functions as a ground conductor.
A ferrite core 6b is placed through b. The soft magnetic body 12 has through holes 14a and 14b for attachment.
is provided. Furthermore, ferrite core 6b
Three central conductors 13a, 13b, and 13c, whose crossing portions are insulated from each other, are placed on top of the conductor at an angle of approximately 120°. Another ferrite core 6a is placed on top of these, and a shield plate 15a is placed over the top of this. Reference numeral 3 denotes a disk-shaped permanent magnet, which is disposed on the shield plate 15a with the magnetic body 11 interposed therebetween. The disk-shaped permanent magnet 3 is magnetized perpendicularly to the disk, and has soft magnetic bodies 11 and 1.
The role is to apply a static magnetic field to the ferrite cores 6a, 6b arranged between the two. Reference numeral 16 denotes a case made of a non-magnetic metal with high thermal conductivity, such as aluminum, brass, stainless steel, etc., and extends over the top of each of the above-mentioned parts.

FIG. 4 is a perspective view of the parts shown in FIG. 3, all tightly assembled using adhesive or the like. FIG. 5 is a sectional view taken along the line AA' in FIG. 4. The soft magnetic material 11 and the permanent magnet 3 are fixed with adhesive.

Here, the center conductors 13a, 13b, 13c are
It is designed to be slightly longer than the soft magnetic bodies 11, 12 and the permanent magnet 3, and when assembled, the center conductors 13a, 13 are as shown in FIGS. 4 and 5.
One end of each of b and 13c protrudes outside the circulator, and the protruding portion is used as a stripline terminal.

The case 16 extends over the circulator and isolator, and is bonded and fixed to the soft magnetic body 12 using an epoxy adhesive or the like. The inside of the case 16 is filled with a filler 18 such as silicone rubber (thermal conductivity 7.5×10 ⁻⁴ cal/cm·sec·°C), and the permanent magnet 3 is buried therein. The circulator and isolator are then fixed onto the heat sink 20 by passing screws through the through holes 14a and 14b attached to the soft magnetic body 12. Also,
The flat resistor 17 is fixed on the soft magnetic body 12.

The purpose of the case 16 is to protect the circulator and isolator, and by providing the case 16, it prevents a worker from accidentally coming into contact with a condenser (not shown in FIG. 5), etc. when installing the circulator and isolator. , which can prevent deterioration of its characteristics.

Considering heat dissipation, which is a feature of the present invention, most of the heat generated inside the circulator/isolator passes through the soft magnetic material 12 and passes through the heat sink 2.
Escape to 0. The remainder is transmitted to the soft magnetic body 12 through the soft magnetic body 11, the permanent magnet 3, the filler 18, and the case 16, and is cooled by the outside air.

In other words, an air layer (thermal conductivity 0.56×10 ^-4 cal/
cm・sec・℃), making it possible to improve heat dissipation.

As for the method of filling the filler 18, it is possible not only to fill it partially as shown in FIG. 5, but also to fill the entire inside of the case 16, which has a better heat dissipation effect than partial filling. It is clear that this is significant.

By using the above structure of the present invention, 1000M
We have achieved a lumped constant circulator/isolator that operates stably in the Hz band. The electrical characteristics include an insertion loss of 0.5 dB and a bandwidth of approximately 8%, making it fully practical.

As is clear from comparing FIG. 5, which shows the cross-sectional structure of the present invention, with FIG. 1, which shows the conventional cross-sectional structure, the present invention has no extra space and is extremely compact. I understand.
Therefore, the area will be 1/3, the height will be 1/2,
It has become extremely small. In addition, the volume has been reduced to 1/6, approximately 3 c.c., which is much smaller than the conventional 18 c.c.

Furthermore, the heat generated by the ferrite cores 6a and 6b when microwave power passes through the case 16 quickly flows into the heat sink 20, so that high power can pass through even if the device is small.

As shown in FIG. 1, when compared with the conventional heat dissipation path through a grounding stand 4 having a large thermal resistance, it will be clear that the improvement of the present invention is significant.

In the embodiments described above, one end of the resistor 17 is connected to any one terminal of the central conductors 13a, 13b, and 13c that come out as a stripline terminal.
This is the case of an isolator whose other end is connected to a ground conductor. In addition, it is well known that the resistor 17 connected to the center conductor 13b can be removed and taken out as a stripline terminal to be used as a circulator.

〔Effect of the invention〕

As described above in detail using several embodiments of the present invention, the structure is extremely simple, so the effects of the present invention are remarkable in terms of miniaturization, cost reduction, and high performance. That is clear.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of conventional products, Figure 3 is a perspective view of each part showing an embodiment of the present invention, and Figure 4 is a cross-sectional view of a conventional product.
The figure is a perspective view of the product of the present invention, and Figure 5 is A- in Figure 4.
It is an A′ cross-sectional view. 3: Permanent magnet, 6a, 6b: Ferrite core,
11, 12: Soft magnetic material, 13a, 13b, 13
c: center conductor, 16: case.

Claims (1)

[Claims] 1. One or more ferrite cores are arranged between two or more soft magnetic bodies, and a permanent magnet is arranged from the outside of one of the soft magnetic bodies, and three or more ferrite cores are arranged in close proximity to the ferrite cores. A lumped constant type circulator and isolator in which one end of each center conductor serves as a stripline terminal for connection to an external circuit, and the ground conductor is placed below the two or more soft magnetic materials. A non-magnetic metal case whose ends are in contact with the soft magnetic material having ^the role of
A lumped constant type circulator and isolator characterized in that they are filled with a filler having a thermal conductivity of cal/cm・sec・℃ or more.