JPS645470B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention includes solid-state circuit components such as solid-state amplifiers and oscillators formed using heat-generating semiconductor elements such as microwave and millimeter-wave high-frequency transistors and diodes. The present invention relates to a high-frequency solid-state device configured as a liquid-cooled high-frequency solid-state device that uses a liquid as a cooling medium.

(b) Background of the technology As mentioned above, this type of high-frequency solid-state device uses heat-generating semiconductor elements such as high-frequency transistors and diodes. Therefore, it is necessary to cool and maintain these semiconductor elements below their functional guarantee temperature.

Conventional cooling methods for high-frequency solid-state devices include natural air cooling and forced air cooling, as described below.
As devices become smaller and more dense, efficient cooling is becoming difficult. By the way, there is a method of using a liquid as a refrigerant, immersing a heating element in this liquid, and cooling it by vaporization and condensation of the liquid. It is known that this liquid cooling method can significantly increase cooling efficiency compared to air cooling, and its application is progressing in various technical fields. The present invention applies this liquid cooling method to construct a liquid-cooled high-frequency solid-state device.

However, when this liquid cooling method is applied to a high-frequency solid-state device, the dielectric constant of the refrigerant (liquid) is different from that of air, and bubbles are generated due to boiling of the refrigerant, which causes the dielectric constant of the refrigerant to changes in high frequency characteristics (amplitude modulation, etc.)
Furthermore, since the density of the refrigerant changes as the temperature of the refrigerant increases, there is another problem that the temperature dependence of high frequency characteristics increases. Therefore, it is desired that a liquid-cooled high-frequency solid-state device has a good cooling function and can solve the above-mentioned problems.

(C) Prior Art and Problems FIG. 1 is a diagram showing a conventional high frequency solid-state device 10 equipped with a microwave amplifier as an example of solid-state circuit components. In the figure, reference numeral 11 indicates a main body of the apparatus, and reference numeral 12 indicates a heat radiation block having a plurality of heat radiation fins 12a and closely fixed to the main body 11 of the apparatus. The device main body 11 is equipped with a field effect transistor (FET) 13 which is a heat generating semiconductor element, and matching circuits 14 and 1 are provided on both sides of the FET 13.
These FETs 13 and matching circuits 14 and 15 are electrically connected to each other to form a microwave integrated circuit. Reference numeral 16 denotes one input connector or output connector, which is electrically connected to the matching circuit 15. This conventional example 10 is configured such that the heat generated by the FET 13 is conducted to the heat radiation block 12 through the bottom plate of the main body 11, and then radiated through the heat radiation fins 12a by natural air cooling or forced air cooling. . However, in this conventional example 10, the cooling capacity (heat dissipation capacity) is about 0.2 W/cm ² in the case of natural air cooling, and about 1 W/cm ² even in the case of forced air cooling, so a large number of FETs 13 are used. If the packaging density is increased, sufficient cooling will not be possible, and this is unavoidable.
It is necessary to widen the mutual spacing between FETs 13. For this reason, this prior art example 10 has a problem in that the connection line between the FETs 13 becomes long, the high frequency loss increases, and the high frequency output decreases.

(d) Purpose of the Invention In view of the above-mentioned problems of the prior art, the purpose of the present invention is to provide a device constructed by applying a liquid cooling method, which has good heat dissipation efficiency, and which has high density heat-generating semiconductor elements. An object of the present invention is to provide a liquid-cooled high-frequency solid-state device that can be sufficiently cooled even when mounted, and can reduce high-frequency loss and changes in high-frequency characteristics (amplitude modulation, etc.).

(e) Structure of the invention In order to achieve the above object, according to the present invention, a heat absorbing and discharging means for cooling liquid vapor is formed at least on the upper wall of a closed container containing a low boiling point cooling liquid, Solid-state circuit components such as solid-state amplifiers and oscillators, which are formed on the bottom wall of a concave casing having an opening on the upper side and are equipped with heat-generating semiconductor elements such as high-frequency transistors and diodes and matching circuits, are cooled in the sealed container. A liquid-cooled high-frequency solid-state device configured by being immersed in a liquid, characterized in that a radio wave absorber is disposed between the upper wall, the heat-generating semiconductor element, and the matching circuit. provided.

(f) Embodiments of the invention Examples of the invention will be described in detail below with reference to the drawings.

FIGS. 2 to 13 are diagrams for explaining embodiments of the liquid-cooled high-frequency solid-state device according to the present invention.
In these figures, the same or corresponding parts are indicated by the same reference numerals.

FIG. 2 is a side sectional view of the first embodiment 20-1, and FIG. 3 is a sectional view taken along line A-A' in FIG. In these figures, the closed container 21 is composed of a box-shaped container main body 22 having an opening on the upper side, and a heat dissipation block (upper wall) 23 which also serves as a canopy and is tightly fixed onto the main body 22. These container bodies 22
Both the heat radiation block 23 and the heat radiation block 23 are made of a material having good thermal conductivity such as copper or aluminum.
The heat dissipation block 23 has a plurality of heat dissipation fins 23a integrally provided on its upper surface, and its lower surface 23b.
is formed as a heat absorbing part. Incidentally, if necessary, heat absorption fins can be further integrally provided on the lower surface 23b of the heat radiation block 23 to enhance the heat absorption effect (for example, see reference numeral 23c in FIGS. 8 and 9). The coolant 24 as a refrigerant is a low-boiling point liquid such as freon or carbon fluoride, which has properties such as chemical inertness and excellent electrical insulation, and leaves appropriate voids on the liquid surface 24a. It is enclosed in a closed container 21. Note that this cavity is normally filled with vapor of the cooling liquid 24.
The solid-state circuit component 25, in this case, is formed as a microwave solid-state amplifier as an example, and includes a box-shaped metal concave housing 26 having an opening on the upper side;
A dielectric circuit board 27 tightly fixed on the bottom wall 26a of the concave casing, and a field effect transistor (FET; exothermic semiconductor element) mounted on the board 27.
28 and input/output matching circuits 29 and 30 (both not specifically shown) provided adjacently before and after the FET 28. The solid circuit component 25 is connected to an input connector 33 and an output connector 34 mounted on the heat dissipation block 23 via connecting coaxial cables 31 and 32, respectively, and is immersed in the cooling liquid 24 and provided with suitable support means. (not shown).
A plurality of radio wave absorbers 35 are arranged and fixed via supports 36 above the FET 28 and the input/output matching circuits 29 and 30, that is, above the solid-state circuit component 25. The radio wave absorber 35 is formed from a material such as ferrite into a conical shape, and its tip 35a
is arranged to face the FET 28 and the input/output matching circuits 29, 30, and its base end 35b is connected to the support 3.
6 is fixed on the lower surface. The support 36 is formed into an elongated shape, and has front and rear ends 36a and 36b.
are fixed inside the closed container 21 by being fastened to the inner surfaces of the front and rear end walls 22a, 22b of the container body 22 with setscrews 37, respectively. By using the support 36 in this way,
There is an advantage that the arrangement position of the radio wave absorber 35 can be adjusted freely. In this case, the radio wave absorber 35 is formed in the shape of a cone as described above, but it may be formed in other sharp shapes such as a pyramid shape or a wedge shape.

By arranging the radio wave absorber 35 in this manner, the electromagnetic waves leaked from the input/output matching circuits 29 and 30 can be efficiently absorbed by the radio wave absorber 35. By forming the radio wave absorber 35 into a sharp object, the radio wave absorber 35 can perform a radio wave absorbing effect better than the tip 35a. On the other hand, if such a radio wave absorber 35 is not provided, the leaked electromagnetic waves rise in the coolant 24 and are reflected at the liquid surface 24a. Further, the leaked electromagnetic waves are also reflected by the boiling bubbles 38 generated in the coolant 24. However, the liquid level 24 due to the bubbles 38
The reflected waves of the leaked electromagnetic waves fluctuate over time due to the influence of the coolant 24 due to fluctuations in a and the upward movement of the bubbles 38, and as a result, the matching conditions of the matching circuits 29 and 30 are changed, causing amplitude modulation. will occur.
Therefore, by providing the radio wave absorber 35 as described above to absorb leaked electromagnetic waves, the influence of the coolant 24 can be suppressed, and therefore amplitude modulation can be suppressed to a minimum. Furthermore, the radio wave absorber 3
It goes without saying that the closer 5 is to the FET 28 and the matching circuits 29 and 30, the less the influence of the coolant 24 will be. However, if it is brought too close, the high frequency loss will increase, so the distance between these two is determined by the influence of the coolant 24. It is preferable to set it to the maximum within an allowable range.

Further, the cooling action (heat dissipation action) of Example 20-1 is performed as follows. A portion of the heat generated by the FET 28 is conducted to the concave casing 26, so that the heat is absorbed by the coolant 24 from the surface of the FET 28 and the surface of the concave casing 26. Due to this heat absorption, a part of the coolant 24 is boiled and vaporized,
The boiling bubbles 38 rise in the coolant 24 .
That is, the heat generated by the FET 28 is absorbed by the heat of vaporization of the coolant 24, and the FET 28 is efficiently cooled. Now, the bubbles 38 that have risen reach the liquid level 24a, and further turn into steam from the liquid level 24a, reach the lower surface 23b of the heat radiation block 23, are absorbed heat by this lower surface 23b, and are liquefied (condensed) again.
and drips onto the cooling liquid 24. On the other hand, the lower surface 23
The heat absorbed by b is efficiently dissipated to the outside by the heat dissipation fins 23a. Due to such heat absorption and heat dissipation actions, the vaporization and liquefaction (condensation) actions of the coolant 24 are continuously repeated. As a result, the FET 28 is continuously cooled and kept stably below its function guarantee temperature.

FIG. 4 is a side sectional view of the second embodiment 20-2, and FIG. 5 is a sectional view taken along the line B-B' in FIG. The present embodiment 20-2 differs from the above-described first embodiment 20-1 only in the mounting form of the radio wave absorber 35, and the other configurations are the same as the first embodiment 20-1. In this case, the radio wave absorber 35 is formed into a wedge shape, and is fixed to the lower surface of the pair of supports 39, respectively. The support 39 is fixed onto the inner surface of the side wall of the concave housing 26 by a set screw 37. By forming the mounting structure of the radio wave absorber 35 in this way,
There is an advantage that the placement position of the radio wave absorber 35 can be accurately determined for the FET 28 where the most bubbles 38 are generated, and amplitude modulation can be effectively reduced. Other functions and effects of this embodiment are substantially the same as those of the first embodiment 20-1 described above. Note that the radio wave absorber 35 may be formed in other shapes as in the case of the first embodiment 20-1.

FIG. 6 is a side sectional view of the third embodiment 20-3, and FIG. 7 is a sectional view taken along the line CC' in FIG. Example 2
0-3 differs from the aforementioned first embodiment 20-1 only in the mounting form and size of the radio wave absorber 35, and the other configurations are the same as the first embodiment 20-1. In this case, the radio wave absorber 35 is formed into a conical and elongated shape, and is fixed on the lower surface 23b of the heat dissipation block 23. By forming the mounting structure for the radio wave absorber 35 in this manner, there is an advantage that the absorber supporting mechanism can be simplified and manufacturing costs can be slightly reduced. And other effects of Example 20-3,
The effect is substantially the same as that of the first embodiment 20-1 described above. Note that the radio wave absorber 35 may be formed in other shapes as in the case of the first embodiment 20-1.

FIG. 8 is a side sectional view of the fourth embodiment 20-4, and FIG. 9 is a sectional view taken along line D-D' in FIG. In this embodiment 20-4, the mounting form of the radio wave absorber 35 and the structure of the heat dissipation block 23 are different from those in the first embodiment 20-4.
1, other configurations are the same as in the first embodiment 20-
It is the same as 1. The heat radiation block 23 has heat absorption fins 23c integrally formed on its lower surface 23b. A conical radio wave absorber 35 is fixed on the lower end surface of the heat absorbing fin 23c. Embodiment 20-4 has the advantage that heat absorption and radiation efficiency can be improved by forming the heat radiation block 23 in this manner and attaching the radio wave absorber 35 as described above. And this Example 20-
Other functions and effects of 4 are as in the above-mentioned first embodiment 20-1.
It is almost the same as. Note that the radio wave absorber 35 may be formed in other shapes as in the case of the first embodiment 20-1.

FIG. 10 is a side sectional view of the fifth embodiment 20-5;
FIG. 11 is a sectional view taken along the line E-E' in FIG. 10. In this embodiment 20-5, the shape of the radio wave absorber 35 and the structure of the heat dissipation block 23 are different from those in the first embodiment 20-5.
-1, the other configuration is the first embodiment 20.
-1 is the same. The heat radiation block 23 has heat absorption fins 23c integrally formed on its lower surface 23b, as in the case of the fourth embodiment 20-4 (FIGS. 8 and 9). In this case, the radio wave absorber 35 is formed in a cylindrical (or prismatic) shape and is fixed on the lower end surface of the heat absorption fin 23c. In this embodiment 20-5, by setting the radio wave absorber 35 in such a simple shape, the radio wave absorber 35
This has the advantage that the processing becomes easier and the manufacturing cost can be slightly reduced, but on the other hand, the radio wave absorption effect is slightly reduced. And this example 20-5
Other functions and effects are substantially the same as those of the first embodiment 20-1 described above.

FIG. 12 is a side sectional view of the sixth embodiment 20-6;
FIG. 13 is a sectional view taken along the line FF' in FIG. 12. This embodiment 20-6 differs from the first embodiment 20-1 only in the shape and mounting form of the radio wave absorber 35 and the structure of the heat dissipation block 23, and the other configurations are the same as those in the first embodiment 20-1. -1 is the same. Heat dissipation block 2
Reference numeral 3 is formed substantially in the same manner as in the case of the fifth embodiment 20-5 described above, and heat absorbing fins 23c are integrally formed on the lower surface 23b. In this case, the radio wave absorber 35 is formed into a plate shape, and includes the lower surface 23b of the heat radiation block 23 and the heat absorption fin 23.
c They are placed in close contact with each other so as to cover the entire surface of both sides.
In this embodiment 20-6, the radio wave absorbers 35 are arranged in close contact with each other in this manner, so that the radio wave absorbers 3
5 can be firmly attached to the heat radiation block 23, but on the other hand, since the thermal conductivity of the radio wave absorber 35 is generally lower than that of the heat radiation block 23, the heat absorption and radiation effect is slightly reduced. . Other functions and effects of this embodiment 20-6 are substantially the same as those of the first embodiment 20-1 described above.

In each of the above embodiments, the whole or part of the radio wave absorber 35 or a part of the heat absorbing fin 23c is immersed in the cooling liquid 24, but the present invention is not limited to this. do not have. In short, it is ultimately important that the radio wave absorber 35 is placed at an optimum distance from the FET 28 and the matching circuits 29, 30. However, it is preferable that a portion of the heat absorbing fins 23c be immersed in the cooling liquid 24 from the viewpoint of heat absorption and radiation.

Further, the present invention is not limited to the above embodiments, and can of course be applied to various modifications without departing from the spirit of the present invention.

(G) Effects of the Invention As explained above in detail, the liquid-cooled high-frequency solid-state device of the present invention transmits radio waves between the upper wall of the closed container having heat absorption and dissipation means, the heat-generating semiconductor element, and the matching circuit. By interposing the absorber, heat dissipation efficiency is good, and even when heat-generating semiconductor elements are mounted in high density, they can be sufficiently cooled and kept stably below their functional guarantee temperature. It has the great effect of reducing loss, and contributes to improved performance and reliability.

[Brief explanation of the drawing]

Figure 1 shows a conventional high-frequency solid-state device, Figure 2
The figure is a side cross-sectional view of the first embodiment 20-1 of the liquid-cooled high-frequency solid-state device according to the present invention, and FIG. 3 is A of FIG.
-A' line sectional view, FIG. 4 is the second embodiment of the present invention.
0-2 side sectional view, Figure 5 is B- in Figure 4.
A sectional view taken along the line B', FIG. 6 is a 20th embodiment of the third embodiment of the present invention.
7 is a sectional view taken along line C-C' in FIG. 6, FIG. 8 is a side sectional view of the fourth embodiment 20-4 of the present invention, and FIG. D-D′ line sectional view,
10 is a side sectional view of the fifth embodiment 20-5 of the present invention, FIG. 11 is a sectional view taken along the line E-E' in FIG. 10, and FIG. 12 is a sectional view of the sixth embodiment 20-6 of the present invention. The side sectional view, FIG. 13, is a sectional view taken along the line F-F' in FIG. 12. 20-1, 20-2, 20-3, 20-4, 2
0-5, 20-6...the first of the present invention, respectively
2, 3, 4, 5, 6 Examples, 21... Sealed container,
22... Container main body, 23... Heat radiation block serving as canopy (upper wall), 23a... Heat radiation fin (heat radiation means), 23b... Lower surface (heat absorption means), 23c... Heat absorption fin (heat absorption means), 24... Coolant, 24a
... Liquid surface, 25 ... Solid circuit component, 26 ... Concave casing, 26a ... Bottom wall, 27 ... Dielectric circuit board, 28 ... Field effect transistor (FET: exothermic semiconductor element), 29 ...Input matching circuit, 30
... Output matching circuit, 35 ... Radio wave absorber, 35a
... Point, 35b... Base end, 36, 39... Support, 38... Boiling bubble.

Claims (1)

[Scope of Claims] 1. A heat absorption/dissipation means for cooling liquid vapor is formed on at least the upper wall of a closed container filled with a low boiling point cooling liquid, and a high frequency transistor is formed on the bottom wall of a concave casing having an opening on the upper side. , a liquid-cooled high-frequency solid-state device constructed by immersing solid-state circuit components such as a solid-state amplifier and an oscillator in a cooling liquid in the airtight container, which is formed by including a heat-generating semiconductor element such as a diode and a matching circuit, A liquid-cooled high-frequency solid-state device, characterized in that a radio wave absorber is disposed between the upper wall, the heat-generating semiconductor element, and the matching circuit. 2. The liquid-cooled high frequency radio wave absorber as set forth in claim 1, wherein the radio wave absorber is arranged and fixed above the heat generating semiconductor element and the matching circuit via a support fixed to the airtight container. solid state equipment. 3. The liquid cooling device as set forth in claim 1, wherein the radio wave absorber is arranged and fixed above the heat generating semiconductor element and the matching circuit via a support fixed to the concave casing. type high frequency solid state device. 4. The liquid-cooled high-frequency solid-state device according to claim 1, wherein the radio wave absorber is fixed to a lower surface of an upper wall of the closed container. 5. The liquid-cooled high-frequency solid-state device according to claim 1, wherein the radio wave absorber is fixed on the lower end surface of a heat absorption fin formed on the lower surface of the upper wall of the closed container. 6. Claim 1, wherein the radio wave absorber is formed into a plate shape and is disposed in close contact with the entire surface of both the lower surface of the upper wall of the closed container and the heat absorption fins formed on the lower surface. liquid-cooled high-frequency solid-state device. 7. Claim No. 7, wherein the radio wave absorber is formed into a sharp object such as a cone shape, a pyramid shape, a wedge shape, etc., and the pointed end thereof is arranged to face the heat generating semiconductor element and the matching circuit. The liquid-cooled high-frequency solid-state device according to any one of items 1 to 5.