JPH01204501A - Large power resistive terminator - Google Patents

Abstract

PURPOSE:To uniformize the heat at each part of an electromagnetic wave absorbing body and to prevent the baking of the electromagnetic wave absorbing body at the input of large power by arranging the electromagnetic wave absorbing body having a curved face to an optimum position. CONSTITUTION:The inner and outer diameters (n), (m) of a center conductor 1 and an outer conductor 2 are decided so that their characteristic impedance is 50OMEGA. The electromagnetic wave absorbing body 3 is configurated so that the electromagnetic wave absorbing body is parted by a distance (z) from the enter conductor 1 at a point (x) toward the axis Z, where (x)=0 at the input terminal of the electromagnetic wave absorbing body 3 and the axis X is taken toward the end, and the distance (z) at the position (x) is decided such that the absorbing ratio of an electromagnetic wave is increased toward the end and the absorbed quantity of the electromagnetic wave is made constant. Since the electromagnetic wave absorbing body 3 is designed so as to have its curved face is provided on the optimum position in a way that the absorbing quantity of the electromagnetic wave at each part is made constant, the heat of each part of the electromagnetic wave absorbing body 3 is made nearly constant and the baking of the electromagnetic wave absorbing body 3 at the input of large power is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-power non-reflection terminator used as a pseudo load that completely absorbs electromagnetic waves without emitting them into space.

[Conventional technology]

Figures 14, 15, 16, 17, 18, and 19 are Emerson &Cumming's Technical Plate 2-6 (gMER8ON & eUMING).
FIG. 2 is a perspective view of a conventional high-power non-reflection terminator disclosed in TECHNICAL BULLETIN 2-6. 14, 15 and 16, 1 is a center conductor, 2 is an outer conductor, 3 is an electromagnetic wave absorber,
In FIG. 7, FIG. 18, and FIG. 19, 4 is a waveguide.

Next, the operation will be explained. The high-power electromagnetic wave incident on the high-power non-reflection terminator shown in these figures travels through a coaxial line or waveguide 4 consisting of a center conductor 1 and an outer conductor 2. The electromagnetic wave absorber 3 absorbs the electromagnetic energy and converts the electromagnetic energy into thermal energy. Due to this conversion, the heat generated in the absorber section is
It is radiated to the outside through the outer conductor 2 or the waveguide 4 and is cooled.

In addition, at this time, since the electromagnetic wave absorber 3 is formed in a stepped or tapered shape, the absorption ratio of electromagnetic waves is small at the input end side and increases toward the terminal end, so that the electromagnetic wave absorption ratio in each part of the electromagnetic wave absorber 3 is small. The structure is such that the difference in the amount of absorption is small and the reflection of electromagnetic waves is reduced.

[Problem to be solved by the invention]

The conventional high-power non-reflection terminator is constructed as described above, and since the electromagnetic wave absorber 3 is formed in a linear taper or step shape, the electromagnetic waves in each part of the electromagnetic wave absorber 3 are reduced. There is a problem in that the amount of absorption is not constant, and the portions where a large amount of electromagnetic waves are absorbed generate more heat, causing the absorber in those portions to burn out when a large amount of power is input.

This invention was developed to solve the above-mentioned problems.The electromagnetic wave absorption amount of each part of the electromagnetic wave absorber is made partial, and the temperature distribution of each part is made uniform, so that electromagnetic waves can be absorbed even when high power is input. The purpose of this invention is to obtain a high-power non-reflection terminator whose body will not be burned out.

[Means to solve the problem]

In the high power non-reflection terminator according to the present invention, the electromagnetic wave absorber has a curved surface, and the position and curved surface are experimentally determined to be optimal so that the amount of electromagnetic wave absorbed in each part of the electromagnetic wave absorber is constant. , are arranged.

[Effect]

Since the electromagnetic wave absorber in this invention is arranged in a curved shape at an optimal position so that the amount of electromagnetic wave absorbed in each part is constant, the heat generation in each part of the electromagnetic wave absorber is almost constant and large. This prevents the electromagnetic wave absorber from burning out when power is input.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a high power non-reflection terminator according to an embodiment of the present invention. In the figure, 1 is a central conductor forming a coaxial line, 2 is an outer conductor forming a coaxial line, and 3 is an electromagnetic wave absorber.

Figure 2 shows a vertical cross-sectional view in the axial direction.
Generally, the dimensions n+ffl of the center conductor 1 and the outer conductor 2 are determined so that the characteristic impedance is 500. Further, the electromagnetic wave absorber 3 is
When the input end of is set to position O, and the direction in which the terminal end goes is set to the X direction, at point X, it is mounted so as to be separated from the center conductor 1 by a distance 2 in two directions. Further, the distance 2 at the position X is determined so that the absorption ratio of electromagnetic waves increases from position to of the input end to the terminal end, and the amount of absorption of electromagnetic waves remains constant. Here, the distance 2 is an important distance for determining the electromagnetic wave absorption ratio of the electromagnetic wave absorber 3 and for making the amount of electromagnetic wave absorbed in each part of the electromagnetic wave absorber 3 constant, and is determined by experiment.

Fig. 3 shows an experimental device for determining the distance 2, in which the distance between the central conductor 1 and the outer conductor 2 is different, the dimensions of which are n in Fig. 2,
The electromagnetic wave absorber 3 is attached to the coaxial line 1 with the same size as m.
It is mounted in a donut shape at a position of = 10 mm + distance 2 from the center conductor 1, and FIG. 4 is a vertical cross-sectional view in the axial direction thereof. Figure 5 is expressed in decibels.

The person in charge will be . However, this is the length of the absorber L = 10mm
If this is the case and the minute part is ΔX, then this part...
...(2) becomes.

Next, in FIG. 1, if the absorbed power of electromagnetic waves in the minute portion ΔX of the electromagnetic wave absorber 3 is S (constant), and the absorbed power of the entire electromagnetic wave absorber 3 is 1, then 8 K -= i...・・・
・(3) ΔX ΔX S;-...(3)' It must be.

Further, ΔX at position fILx is located at the position from the input end.

The ratio between the input power W1 and the absorbed power at the n-th ΔX is yl= □ ......(5) 1-(n
-1) S.

Here, substituting equations (3)' and (4) into equation (5),
ΔX.

Furthermore, when this is expressed as a ratio of input power to output power W2, it becomes ``.

If we convert this to Dempel display, ・・・・・・(8) becomes.

This is the ratio of input power and output power required for the electromagnetic wave absorber of the nth ΔX portion. Therefore, equation (8) and C)
Calculating the digit tx and the distance 2 from the center using the formula, we get... (9) Solving this for the distance 2, log -... (10) This can be understood mathematically. Using the method described in 6) (→0), the limit value is found as follows.

However, in this case, distance 2 is a negative number, but distance 2 cannot be brought any closer to the center conductor, and it remains in close contact with center conductor 1, but this is sufficient for practical purposes. be. This is because in equation (12), for example, in Figure 1, if A = 200 mm, then equation (12) becomes, and when this is solved for X, x > 194 and distance 2
is a negative number. However, this is because 1:X100% of electromagnetic waves have already been absorbed by the electromagnetic wave absorber 3 up to x=194.

In the above embodiment, a coaxial line is used, but the same effect can be achieved using a waveguide as shown in FIG. In Fig. 6, 4 is a waveguide;
3 is an electromagnetic wave absorber, and FIG. 7 is a sectional view thereof.

The electromagnetic wave absorber 3 is located at a distance 2 from the wall of the waveguide so that the absorption ratio of electromagnetic waves increases as it goes from the input end to the terminal end, and the amount of electromagnetic wave absorption in each part of the electromagnetic wave absorber 3 is constant. It is configured to be. Here distance 2
However, it is determined by the experimental apparatus shown in FIG. Although FIG. 9 is a cross-sectional view of the same, it is possible to obtain the actual value, and the distance 2 at the position xK is determined by the same calculation. Although the radio wave absorber described above is configured three-dimensionally, a flat structure is also effective. Further, FIG. 10 shows an example in which the present invention is applied to a microstrip line. In the figure, 5 is a microstrip line and 3 is an electromagnetic wave absorber.

FIG. 11 is a view seen from the top, and similarly shows that the electromagnetic wave absorber 3 is placed at a distance of 2. FIG. 12 shows an experimental apparatus for determining the distance 2, and FIG. 13 shows a top view of the apparatus, from which the experimental distance 2 is determined.

〔Effect of the invention〕

As explained above, according to the present invention, since the electromagnetic wave absorber having the optimal flK curved surface is arranged, the heat generation in each part of the electromagnetic wave absorber becomes uniform in terms of tl, and even when high power is input, the electromagnetic wave absorber is burnt out. This has the extremely excellent effect of providing a high-power, non-reflection terminator that does not cause any damage.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a high power non-reflection terminator according to an embodiment of the present invention, FIG. 2 is a sectional view of FIG. 1, and FIG. FIG. 4 is a sectional view of FIG. 3, FIG. 5 is a graph of experimental values, FIG. 6 is a perspective view of another embodiment of the present invention, and FIG. 7 is a sectional view of FIG. FIG. 8 is a perspective view of the experimental apparatus for determining distance 2 in this embodiment, and FIG. 9 is a cross-sectional view of
The figure is a sectional view of FIG. 8, FIG. 10 is a perspective view showing still another embodiment of the invention, FIG. 11 is a plan view seen from above of FIG. 10, and FIG. 12 is a distance diagram in this embodiment. FIG. 13 is a perspective view of the experimental apparatus used to determine 2, and FIG. 14 is a plan view seen from above of FIG. 12. Figures 15 and 16 show conventional high-power non-reflection terminators configured in coaxial lines, and Figures 17, 18, and 19 show conventional high-power non-reflection terminators configured in waveguides. It is. 1...Center conductor, 2...Outer conductor, 3...
Electromagnetic wave absorber, 4... waveguide, 5. fist... microstrip line.

Claims (1)

[Claims] An electromagnetic wave absorber having a curved surface part is provided in the electromagnetic wave transmission path, and the curved surface part is made into a curved surface such that the absorption ratio of electromagnetic waves increases from the input end toward the terminal end and the amount of electromagnetic wave absorption in each part is almost constant. A high power non-reflection terminator characterized by