JPH01126801A - Superconducting waveguide - Google Patents

Abstract

PURPOSE:To transmit an electromagnetic wave with low loss by forming a superconducting thin film made of a ceramics group superconducting material to the inner face of a waveguide. CONSTITUTION:A square superconducting waveguide G1 is arranged in a transportation pipe 10 of similar square shape and a superconducting thin film 1 made of an optional material in ceramics group superconducting materials is formed to the inner face of the superconducting waveguide G1. Then a coolant is provided on a gap between the superconducting waveguide G1 and the transportation pipe 10. The electric resistance of the superconducting thin film 1 is lost by the coolant and the critical temperature when the Meissner effect appears is maintained. Thus, the power of an electromagnetic wave is sent with less loss.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a superconducting waveguide having a superconducting thin film made of a ceramic superconducting material.

[Problems to be solved by conventional technology/inventions] Superconducting phenomenon refers to a phenomenon in which electrical resistance completely disappears below the temperature at which this phenomenon occurs (critical temperature).
differs depending on the material. Since materials with high critical temperatures can be easily cooled, the development of materials with as high critical temperatures as possible has been particularly popular recently. In addition to a high critical temperature, the upper limit of current that can be passed in a superconducting state (critical current) is also an important point for the practical application of ceramic materials. For practical use, this must be made into a wire, for example, but since the current that can be passed through ceramic materials per unit cross-sectional area is currently small, the key to practical application is how high a critical current can be obtained. This is because

Alloy-based and compound-based materials are well known as materials that cause superconductivity, and recently, the development of ceramic-based materials has been particularly advanced. The development of ceramic superconducting materials with high critical temperatures is progressing rapidly, but in order to put them into practical use, it is necessary to process superconducting materials into wires, tapes, coils, etc. To make a powerful electromagnet, it must be processed into a coil. However, ceramics made from powdered materials are hard and brittle, and it is extremely difficult to process them, such as bending them like alloys or winding them into coils. Therefore,
In order to overcome these drawbacks and bring them closer to practical use, progress is being made in the development of ceramic materials and processing methods.

One important point in the practical application of superconducting ceramic materials is how to make them into devices without deteriorating their superconducting properties, and the key to this is the production of thin films of ceramic materials. The development of thin films for ceramic superconducting materials is essential for the application of superconductors to a wide range of fields such as energy, including the field of electronic devices, and the current state of the art is that the development of thin films is becoming more and more competitive.

By the way, a waveguide is a hollow tube for power transmission of electromagnetic waves such as ultralong and short waves (frequency range from microwave to millimeter wave), and energy is transmitted by the progress of electric and magnetic fields generated in the tube. . Depending on the shape, there are rectangular waveguides, circular waveguides, elliptical waveguides, torsion waveguides, curved waveguides, Taber waveguides,
There are branch waveguides that connect multiple waveguides.

Waveguides have become affordable in size in the microwave band or higher frequency range, and because they are hollow tubes, the transmission loss is almost one order of magnitude lower than that of coaxial cables, and the transmission power is greater than that of coaxial cables. Although it is widely used for several reasons, it is inevitable that there will be some transmission loss. For example, as shown in Figure 4, there is a tendency for the attenuation to increase as the transmission power increases.
Codes such as 1, 1, 4, and 2 represent domestic standards for rectangular waveguides, and the smaller the number, the larger the inner diameter and the lower the frequency of the transmitted power. In other waveguides, as in the case of rectangular waveguides, the amount of attenuation tends to increase as the transmission power increases.

Therefore, in view of the above points, an object of the present invention is to provide a waveguide that can transmit high power with lower loss.

[Means for solving problems]

The above object is achieved by a superconducting S waveguide characterized in that a superconducting thin film made of a ceramic superconducting material is formed on the inner surface of the waveguide.

The superconducting waveguide of the present invention is characterized by forming a superconducting thin film made of ceramic superconducting material on the inner surface of the waveguide, which has the effect of almost eliminating electrical resistance and eliminating heat loss. Therefore, it is a waveguide that can transmit high power with low loss. Further, as an example of this, in order to maintain the superconducting state of the superconducting thin film more efficiently, the superconducting waveguide may be arranged in a hollow transport pipe through which a cooling medium is passed, or a plurality of superconducting waveguides may be arranged. Similarly, one example is one arranged in a transport pipe through which a refrigerant is passed inside.

In the superconducting N waveguide of the present invention, the waveguide to be used is not particularly limited, and any normal waveguide may be used.

Waveguides are usually made of materials such as aluminum or copper;
In order to form a superconducting thin film on the inner surface of a waveguide made of these materials and to provide flexibility for easy installation, the waveguide should be made of aluminum or the like. is preferred.

In the superconducting waveguide of the present invention, the ceramic superconducting material that is the material of the superconducting thin film formed on the inner surface of the waveguide is not particularly limited. , erbium, thulium, yttrium, strontium, etc.). Existing materials may be used as such materials, but for example, barium, yttrium, etc.
Copper/oxygen, barium/lanthanum/copper/oxygen, strontium/lanthanum/copper/oxygen, barium/scandium/
There are ceramics with a composition of copper/oxygen, calcium/lanthanum/copper/oxygen, etc., and preferably a material with a composition of barium, yttrium, copper, and oxygen, which is an yttrium-based material that is becoming mainstream in ceramic materials.

Furthermore, as an example, when using this yttrium-based superconducting material, the preferred blending ratio is Ba: Y: Cu:
O=2:l:3:5-7.

In the present invention, a ceramic material having such a composition is used. The method for producing the material may be any conventionally known method and is not particularly limited. For example, raw material powder (for example, in the case of the yttrium-based superconducting material of barium, yttrium, copper, and oxygen, barium carbonate,
It may be manufactured by a solid-state process that involves mixing yttrium oxide, copper oxide, etc. → sintering → re-powdering the sintered body. Furthermore, in the present invention, a mixture of raw material powders such as barium carbonate, yttrium oxide, and copper oxide can also be used.

The obtained ceramic superconducting material powder or a mixture of its raw material powders is used to form a superconducting thin film on the inner surface of a waveguide.

The transport pipe for arranging the superconducting waveguide, which is an embodiment of the present invention, only needs to exhibit corrosion resistance, cold resistance, magnetic resistance, etc. to the cooling medium introduced into the pipe. For example, aluminum,
It is made of materials such as copper and stainless steel. Furthermore, the cooling medium passed through this transport pipe is used to maintain the superconducting state of the superconducting thin film, and the cooling medium used is also used due to the critical temperature of the superconducting thin film, that is, the ceramic superconducting material that is the material of the superconducting thin film. Although different,
There are liquid helium, liquid nitrogen, dry ice, etc. The cooling temperature of liquid helium is 4K, the cooling temperature of liquid nitrogen is 77K, and the cooling temperature of dry ice is about 196K, depending on the cooling temperature of these cooling media. It is important to appropriately select a ceramic superconducting material that becomes superconducting at this critical temperature.

〔Example〕

Hereinafter, the superconducting waveguide of the present invention will be described in more detail based on Examples.

FIG. 1 shows an example of this, in which a rectangular superconducting waveguide G1
are disposed within the transport pipe 10 having a phase-oriented shape. On the inner surface of the superconducting waveguide G1, a superconducting 8m film 1 made of any material among the ceramic superconducting materials mentioned above is formed. Here, an example of the thickness of the superconducting thin film 1 of this rectangular superconducting waveguide G1 is shown. Although it depends on the standard and the size of the waveguide, the inner diameter of the waveguide is the long side x
Short side = 109.22~12.954X 54.61~6
．． 1000 to 1 house for 477 barrels, preferably 500
~20-1, particularly preferably 100-1. The superconducting waveguide G1 is held at a substantially central position within the transport pipe 10 by rectangular supporting members 11 made of aluminum, stainless steel, copper, etc. provided on each inner surface of the transport pipe 10.

A cooling medium (not shown) communicates with the gap between the superconducting waveguide G1 and the transport pipe 10. The cooling medium allows the superconducting thin film 1 to maintain its superconducting state, that is, the critical temperature at which the electrical resistance of the superconducting thin film 1 disappears and the Meissner effect appears, and the superconducting thin film 1 in this superconducting state allows the power of electromagnetic waves to be maintained with extremely low loss. It can be transmitted by

This is because, as mentioned above, the superconducting thin film 1 has almost no electrical resistance, so it has the effect of causing no heat loss. In this way, simply by forming an extremely thin superconducting thin film on the inner surface of the waveguide, a superconducting waveguide with unprecedentedly low transmission loss can be realized.

FIG. 2 shows another embodiment, in which an elliptical superconducting waveguide G2
are arranged in the transport pipe 20 having a similar elliptical shape. A superconducting thin film 3 made of a ceramic superconducting material is formed on the inner peripheral surface of the superconducting waveguide G2. Similar to FIG. 1, the superconducting waveguide G2 is placed inside the transport pipe 20
The central position is maintained by a support member 21 provided on the inner peripheral surface of the superconducting waveguide G2, and a cooling medium (not shown) is communicated with the gap between the transport pipe 20 and the superconducting waveguide G2. This elliptical superconducting waveguide is long and flexible, making it easier to install than rectangular or circular waveguides, and has many other advantages. In this embodiment as well, electromagnetic waves can be transmitted with low loss as in the embodiment shown in FIG.

In the above embodiment, one superconducting waveguide is arranged in the transport pipe, but as shown in FIG. This shows the case where it is placed.

This consists of multiple rectangular superconducting waveguides G1 shown in Figure 1 (
In this figure, the cooling medium occupies not only the gap between the bundled superconducting waveguide G1 and the transport pipe 30, but also the gap between the superconducting waveguides G1. Cooling is performed efficiently. If multiple superconducting waveguides are used in a bundle as in this embodiment, the required space can be saved, and moreover, multiple superconducting waveguides can be cooled at once by the cooling medium in the transport pipe. The cooling cost for maintaining the superconducting state of the superconducting thin film can also be kept low.

There are no particular limitations on the method for manufacturing a superconducting waveguide having the structure described above. For example, the main methods for manufacturing the waveguide itself include:
When manufacturing short waveguides (within 5 m) individually and using them in a bundle as shown in Fig. 3, the supporting material 3 is used.
1, it is sufficient to use the method of fixing it inside the transport pipe 30, and when constructing a long waveguide, there are methods such as flange connection. It is formed by applying a superconducting thin film made of the material and then sintering it.

The thickness of the superconducting thin film formed on the inner surface of the waveguide varies depending on the type and size of the waveguide and its material. For example, in the case of an elliptical waveguide, the inner diameter is the long axis x short axis. =
63.38-41.4X38.12-25.0 for 6 of about 1000-500-1 preferably 800
~600 units, long axis x short axis -37.4~24.5X2
500 to 2 for those with 2.5 to 12.25 barrels
00 μm, preferably about 400 to 300 units, long axis x short axis -22,75 to 14.6 x 10.5 to 6.7 + mn
200 to 10 Pm, preferably 1
It is sufficient if the amount is about 00 to 50 μm.

〔Effect of the invention〕

As explained above, according to the superconducting waveguide of the present invention, since a superconducting thin film made of ceramic superconducting material is formed on the inner surface of the waveguide, electromagnetic waves can be transmitted with extremely lower loss than conventional ordinary waveguides. This is a revolutionary technology that can be transmitted.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of one embodiment of the superconducting waveguide of the present invention, FIG. 2 is a partially cutaway perspective view of another embodiment, and FIG. 3 shows a plurality of waveguides of FIG. Figure 4, which is a partially cutaway perspective view of the embodiment used, is a graph showing the relationship between attenuation and transmitted power with respect to frequency in a rectangular waveguide.The attenuation is calculated assuming that the waveguide is made of pure copper. The peak current is 23°C inside the waveguide.
Calculations were made assuming that the air was filled with a pressure of 760 mmHg, and the discharge voltage of the air was assumed to be 4200 V/cm. G1, G2; Superconducting waveguide 1.3: Superconducting thin film 10.20.30: Transport pipe 11.21.31: Support material Figure 4 Attenuation and transmission power of rectangular waveguide 6-

Claims (3)

[Claims] (1) A superconducting waveguide characterized in that a superconducting thin film made of a ceramic superconducting material is formed on the inner surface of the waveguide. (2) The superconducting waveguide according to claim (1), wherein the superconducting waveguide is disposed in a hollow transport pipe through which a cooling medium is passed. (3) The superconducting waveguide according to claim (1), wherein a plurality of the superconducting waveguides are arranged in a bundle in a hollow transport pipe through which a cooling medium is passed. .