JPH0566761B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a crossing circuit of strip-shaped lines for high-frequency circuits that intersect in the same plane.

(Prior art and problems) Figure 1 is a diagram showing a conventional method of crossing strip lines, where 1 is the center conductor of the strip line,
2 and 2' represent metal base plates, and 3 represents a coaxial line.

Normally, the strip line can be bent, branched, etc. on a plane parallel to the metal ground plates 2, 2', and can be wired with some degree of freedom. However, when two strip lines intersect, it is impossible to directly intersect them without affecting each other.

In other words, if a gap is provided at the intersection of the center conductors, there will be no mutual influence in terms of direct current, but in reality, in order to transmit high-frequency signals, displacement current flows through the gap, causing capacitive coupling and mutual influence. It was impossible to eliminate it. Therefore, the method shown in FIG. 1 has been used as a means for crossing strip lines.

In FIG. 1, two strip lines are once converted into a coaxial line 3. Since the coaxial lines 3 can be bent freely, it is easy to cross them. After crossing with coaxial line, it is converted to strip line again. In coaxial lines, the influence between the lines can be ignored, so strip lines can be crossed in this way.

However, this method has the disadvantage that the structure of the converter between the strip line and the coaxial line is complex and requires many processing steps, resulting in high manufacturing costs.
It is difficult to accurately set the amount of phase shift in a curved coaxial line, and the structure is complicated, which has the disadvantage of deteriorating transmission loss and VSWR characteristics.

(Objective of the Invention) In order to eliminate these drawbacks, the present invention realizes a cross circuit of strip lines with a simple structure and no coupling between lines. This will be explained in detail based on the following.

(Embodiment of the Invention) Figs. 2 to 4 are views showing an embodiment of the present invention, in which Fig. 2 is a perspective view, Fig. 3 is a side view, and Fig. 4 is a perspective view.
The figure is a top view.

In FIGS. 2 to 4, 1 and 1' are strip lines, 2 and 2' are metal ground plates, and 4 is a saddle-shaped conductor plate.

The saddle-shaped conductor plate 4 is attached in contact with the upper metal ground plate 2 and the lower metal ground plate 2', and serves both as a ground plate and to separate the two lines.

In FIG. 2, the strip line 1 has a saddle-shaped conductor plate 4, which is equivalent to the lower metal base plate becoming higher due to the presence of the saddle-shaped conductor plate 4, and the gap between the upper and lower metal base plates becoming narrower. Therefore, the height of the strip line 1 is gradually changed and the strip line is always positioned between the upper and lower metal base plates.

A strip line has a characteristic impedance determined by the distance to the upper and lower metal ground plates and the width and thickness of the strip line. When the characteristic impedance of a line changes depending on location, reflections occur there and the transmission characteristics deteriorate. Therefore, the characteristics are better if the characteristic impedance does not change even in the portion where the saddle-shaped conductor plate 4 is present.

When the distance to the upper and lower metal ground plates becomes smaller, the characteristic impedance can be kept constant by narrowing the width of the strip line, so the width of the strip line becomes gradually narrower as shown in Figure 4. Shape. Since the distance between the metal ground plate and the strip line 1 is constant at the portion where the strip line 1 intersects the strip line 1', the width of the strip line is also constant. The width and height of the stripline 1 past the intersection change in a manner symmetrical to the shape all the way to the intersection, returning to the original stripline shape.

The shape of the strip line 1' is also exactly the same as 1.

If the area where the saddle-shaped conductor plate 4 contacts the metal base plate is made larger, capacitive coupling will result in electrical continuity even if there is a slight gap between the saddle-shaped conductor plate 4 and the metal base plate, so soldering, etc., is not necessarily required. It has the advantage that it does not need to be fixed.

In the case of the configuration shown in Figure 2, the strip line 1
The intersection of 1 and 1' is blocked by a saddle-shaped conductor plate 4 that is in contact with the metal ground plate, so that coupling between the strip lines does not occur. Furthermore, since the characteristic impedance is constant, there is also the advantage that no reflection occurs.

Note that the shapes and bent portions of the saddle-shaped conductor plate and the strip line may be formed with smooth curved surfaces. Further, the width of the saddle-shaped conductor plate may increase as it approaches the metal base plate from the intersection,
In this case as well, each strip line has good transmission characteristics.
A cross-circuit with less coupling between lines can be obtained.

FIG. 5 is a diagram showing another embodiment of the present invention, in which the shape of the saddle-shaped conductive plate is different from that of the previous example, and 5 shows a triangular conductive plate between each tongue piece. This shows the saddle-shaped conductor plates connected together. Fifth
By using a saddle-shaped conductor plate shaped as shown in the figure, the coupling between the lines can be further reduced and a cross circuit with good characteristics can be obtained.

FIG. 6 is a diagram showing an example in which a cross circuit is modularized.

As shown in Figure 6, by modularizing the saddle-shaped conductor plate, the strip line near it, and the upper and lower metal ground plates, and fitting and connecting them at the intersection of the strip lines, it is possible to form a complex circuit. It is easy to process.

(Effects of the Invention) As explained in detail above, the strip line crossing circuit according to the present invention has a simple structure, so that
It has the advantage that it is easy to manufacture, has little coupling between each line, and can obtain good transmission characteristics.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional method of crossing strip lines, FIGS. 2 to 4 are diagrams showing one embodiment of the present invention, and FIG. 5 is a diagram showing another embodiment of the present invention. FIG. 6 is a diagram showing an example in which the cross circuit is modularized. 1, 1'... Strip line, 2, 2'... Metal ground plate, 3... Coaxial line, 4... Saddle-shaped conductor plate, 5...
...A saddle-shaped conductor plate that connects each tongue piece with a triangular conductor plate.

Claims (1)

[Claims] 1 A circuit using a strip line installed between two opposing planar conductive plates through a gap or a dielectric, with tongue strips in four directions (vertical and horizontal) of the surface of the small conductive plate. and a saddle-shaped conductor plate formed by bending each tongue at a certain angle so that the vertical tongue piece and the horizontal tongue piece are in opposite directions with respect to the surface of the conductor plate small piece. Said 2 placed
The tip of each tongue is disposed inside the plane conductor plate so that it is in contact with the plane conductor plate, and the tip part of each tongue is disposed inside the plane conductor plate, and passes through the two spaces created by being surrounded by the tongue and each plane conductor plate. It has a structure in which two strip lines are arranged so as to intersect with each other. Each dimension is
A strip line crossing circuit characterized in that the characteristic impedance of the strip line is determined to be substantially constant over a portion where the saddle-shaped conductor plate is present and a portion where the saddle-shaped conductor plate is not present.