JPS6333322B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuously variable delay line that can be used at high frequencies and high power.

Conventional delay lines made by stacking C and L distributed constant circuits or lumped constant circuits have very limited frequencies and are mostly usable only at low power, but cannot be used at high power. Have difficulty.

On the other hand, as a delay circuit for high power, for example, there is one that uses a coaxial line and changes the electrical line length by varying the position of the termination of the coaxial circuit. However, this type of delay circuit requires precision in its mechanism and also requires a length equivalent to the line length, making it difficult to reduce the external dimensions.

The present invention provides a continuously variable delay line whose termination position can be continuously changed using a simple mechanism using a cylindrical strip line, and whose external dimensions are small.

1 is a longitudinal sectional view of a variable delay line made of a strip line for explaining the principle of the present invention, and FIG. 2 is a sectional view taken along the line X--X in FIG. 1.

The variable delay line in Figure 1 has ground conductors 1a and 1b.
on one surface of the dielectrics 2a and 2b.
Two strip lines AB and CD with strip lines 3a and 3b placed on the other side of a and 2b, and a shorting member 4 for shorting the strip lines 3a and 3b.
It is made up of. Assuming that point A is the input point and point C is the output point on the delay line in Figure 1, the delay time required to propagate from input point A to output point C is
It can be changed by moving the shorting member 4.

Note that the above delay time is based on the line length l from A to C.
is a function of the characteristic impedance Z ₀ of the strip line, and Z ₀ of the strip line can be found using equation (1).

Z ₀ = (h/b) (μ/ε) ^1/2 / {1 + (2h/πb) (1+ln (1+πb/2b))}...(3
) Here, h is the thickness of the dielectric, b is the width of the strip line, μ is the magnetic permeability of the conductor, and ε is the permittivity of the dielectric.

The delay line using strip lines shown in FIGS. 1 and 2 cannot be used as is. The reason is that the short-circuiting member 4 of the strip line
The surplus impedance of the surplus portion from the position to the end points B and D of the strip line is added in parallel to the impedance from the point A and C to the position of the shorting member 4, and this surplus impedance largely depends on the length of the surplus portion. This is because it changes.

Figure 3 shows the second step to eliminate the influence of the surplus part.
FIG. 3 is a perspective view of a delay line including a shorting member.

In the delay line of FIG. 3, the ground conductors 1a, 1b and dielectrics 2a, 2b of the delay line of FIG. 1 are integrated into a ground conductor 1 and dielectric 2, respectively.
Two strip conductors 3c and 3d are placed on the dielectric.
, the strip conductors 3c and 3d are short-circuited at point P by the first short-circuiting member 4', and further, the strip conductors 3c and 3d are short-circuited at point P by the first short-circuiting member 4', and a conductor in the surplus portion separated by a distance of λ/4 (λ: wavelength used) from the short-circuiting member 4' is The delay line is provided with a second shorting member 5 that shorts the strip conductors 3c and 3d at point Q.

The second shorting member 5 connects the strip lines 3c and 3d.
In addition to short-circuiting the
4 and moves in conjunction with the first shorting member 4'.
As a result, for strip conductors 3c and 3d, the impedance seen from point P to point Q (that is, looking at the surplus portion) is always infinite, and even if the first shorting member 4 is moved, the impedance of the surplus portion remains constant. It can be done. In this way the second
By using the short-circuiting member 5, it becomes possible to put a delay line using a strip line into practical use. However, the delay line of FIG. 3 has the disadvantage that it requires external dimensions comparable to the line length of the delay line.

The present invention uses a cylindrical strip line, a first short-circuiting member, and a second short-circuiting member to create a delay line that can stably change the delay time without being affected by surplus parts, and that is also small. This is what we provide.

FIG. 4 is a conceptual partially sectional front view of an embodiment of a delay line according to the present invention.

The delay line in FIG. 4 consists of a cylindrical dielectric 6, a cylindrical ground conductor 7 closely disposed on its inner surface, and a spiral line along the outer surface of the cylindrical dielectric 6 so as not to touch each other. Two strip conductors 8 and 9 are arranged, and a first strip conductor 8 and 9 is movably arranged outside the cylindrical dielectric body 6 and short-circuits the strip conductors 8 and 9.
A shorting member 10 is movably disposed outside the cylindrical dielectric 6 in conjunction with the first shorting member to maintain a distance of 1/4 wavelength along the spiral line, and the strip conductor 8 and a second shorting member 11 that short-circuits and 9 and is grounded.

Since the delay line shown in FIG. 4 has a structure in which the delay line shown in FIG. 3 is spirally wound, its outer shape can be made smaller than the electrical line length of the delay line. The electromagnetic properties are the same as those of the delay line in FIG. The delay time can be stably changed by eliminating the influence of the second shorting member 11 which is grounded at a position 1/4 wavelength from the first shorting member 10.
Note that the second short-circuiting member 11 can be grounded, for example, by sliding it on a grounding body (not shown) disposed outside the cylinder.

Since the delay line according to the present invention has the above-described structure, it can be used as a high-power delay line because it basically has less heat loss and has better heat dissipation efficiency than conventional delay lines even when heat is generated. .

As explained above, the delay line of the present invention can be used for high frequency and high power applications even though it is small in size, so it can greatly contribute to the development of industry. Note that the technical idea of the present invention is not limited to that embodied in FIG. It is also possible to arrange a ground conductor 7 inside the dielectric 6, arrange three strip conductors in a spiral shape outside the dielectric 6, and connect one of them to another ground conductor. It is also included within the scope of the technical idea.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of a variable delay line for explaining the principle of the present invention, and Figure 2 is a cross-sectional view taken along the line XX in Figure 1.
3 is a perspective view of the principle delay line provided with the second short-circuiting member, and FIG. 4 is a conceptual partially sectional front view of an embodiment of the delay line according to the present invention. 6... Dielectric, 7... Earth conductor, 8, 9...
Strip conductor, 10... first shorting member, 11...
...Second shorting member.

Claims (1)

[Scope of Claims] 1. A cylindrical dielectric, a cylindrical ground conductor disposed closely on one surface thereof, and a cylindrical ground conductor disposed along the other surface of the cylindrical dielectric so that they do not touch each other and are threaded. two strip conductors linearly arranged; a first shorting member movably disposed on the other surface of the cylindrical dielectric and shorting the two strip conductors; and the cylindrical dielectric. the first on the other side of the body;
It is movably arranged in conjunction with the shorting member to keep the distance along the spiral line equal to 1/4 wavelength, and the above two strip conductors are short-circuited and further grounded to earth. A continuously variable delay line comprising a second shorting member. 2. The continuously variable delay line according to claim 1, wherein the cylindrical ground conductor is disposed inside the cylindrical dielectric.