JPS636904A - Power distribution circuit - Google Patents

Abstract

PURPOSE:To improve the power distribution characteristic over a broad band by providing an impedance transformer to a connecting part between a conductor plate and a center conductor of a coaxial line. CONSTITUTION:The center conductor 2 of the coaxial line and a front ridge 51 of the conductor plate 5 branched in parallel with the H palne are connected via the impedance transformer 6. The transformer 6 has both side ridges which are tapered smoothly from the front ridge 51 to the center conductor 2 of the coaxial line. That is, distances r1, r2 between both the side ridges of the conductor plate of the transformer 6 and both the side faces of a rectangular waveguide 1 are designed so as to be changed smoothly as a curve. Thus, the impedance conversion is applied smoothly at the impedance transformer part 6 and the impedance matching is attained between the coaxial line and the waveguide. Thus, the input/output impedance and the power distridution characteristic at all the input/output terminals are improved over a broad frequency band.

Description

TECHNICAL FIELD The present invention relates to a power distribution circuit, and more particularly to a power distribution circuit having a coaxial waveguide conversion function.

BACKGROUND ART An example of a conventional power distribution circuit of this type is shown in FIG. 12, which is a perspective view including a partially broken surface. A dividing conductor plate 5 is attached to the inside of the rectangular waveguide 1 and is provided parallel to the H plane to divide the inside into two parts. The front edge 51 of the conductor plate 5 is perpendicular to the E plane of the waveguide 1, and a coupling hole 3 with a coaxial line is bored in a portion of the front edge 51 close to the E plane. There is. In this coupling hole 3, the coaxial line and the waveguide are electrically coupled.

For this purpose, the center conductor 2 of the coaxial line is electrically connected to a portion of the front edge 51 of the conductor plate 5 that is desired to be connected to the coupling hole 3.

Further, the outer conductor 4 of the coaxial line is electrically connected to the E plane of the waveguide, but it does not appear on the drawing in FIG.

When a device with such a configuration is used as a power distribution circuit, for example, the power supplied from a coaxial line is divided into waveguide paths formed above and below this conductor plate 5 in the same phase by the action of the conductor plate 5. Power is then supplied to the waveguide 1.

In this type of power distribution circuit, the characteristic impedance Zoc of the coaxial line is as shown in Figure 13. If the ratio is ε, then Z = (138/7)flo(1(R/r)C. - Generally, in a coaxial line in the microwave band, it is 50Ω.

On the other hand, the characteristic impedance Z of the rectangular waveguide. r is the first
As shown in Figure 4, if the lateral dimension of the waveguide 1 is a, 1 dimension, and the wave impedance is Zll, then 2o, = 2. ＜π
b/2a). In the branch waveguide, the ratio of the horizontal dimension a to the vertical dimension is approximately 4:1, so Zo- is approximately 180Ω.
becomes.

If we consider the connection between the terminal of the coaxial line and the branch waveguide, the circuit will be as shown in Figure 15, and therefore the input impedance Z as seen from the terminal of the coaxial line will be Zor
are connected in parallel, so it becomes 1/2 of n Zor and becomes about 90Ω.

By the way, in this type of conventional power distribution circuit, the coaxial line and the branching conductor plate 5 are directly connected as shown in FIG. Therefore, the characteristic impedance Z of the coaxial section
. 0 and the input impedance Zio of the branch waveguide are 50Ω and 90Ω, respectively, which are significantly different from each other.

As a result, the input VSWR (voltage standing wave ratio) of the coaxial terminal and branch waveguide deteriorates, the frequency band in which impedance matching can be achieved becomes narrower even if adjusted with adjustment screws, etc., and the power distribution characteristics also become narrowband. There is a drawback.

The present invention has been made to solve the above-mentioned drawbacks of the conventional circuits, and its purpose is to provide a power distribution circuit that can provide good power distribution characteristics over a wide band. It is in.

Structure of the Invention According to the present invention, there is provided a rectangular waveguide, a conductor plate provided parallel to the H-plane of the waveguide to divide the inside of the rectangular waveguide, and an outer conductor that is connected to the waveguide. a coaxial line connected to one side of the conductive plate and having a center conductor connected to the conductive plate, the power distribution circuit comprising an impedance transformer at a connection portion between the center conductor of the coaxial line and the conductive plate. A power distribution circuit characterized by the following characteristics is obtained.

Example Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a perspective view including a partially broken surface of an embodiment of the present invention, and parts equivalent to those in FIG. 12 are indicated by the same reference numerals. As shown in the figure, in the present invention, the front edge 51 of the conductor plate 5 for branching parallel to the H plane and the center conductor 2 of the coaxial line
are connected via an impedance transformer 6, unlike the conventional example shown in FIG. 12 (in the conventional example, these two are directly connected).

This impedance transformer 6 has smooth tapered side edges between the front edge 51 of the conductor plate 5 and the center conductor 2 of the coaxial line. That is, the distance ll1i between both side edges of the conductor plate constituting the transformer 6 and both side surfaces (corresponding to one surface) of the rectangular waveguide 1
The structure is such that r and r2 each change smoothly in a curved manner.

By doing this, impedance conversion is performed smoothly in this impedance transformer portion 6,
In-vehicle matching between the coaxial line and the waveguide becomes possible. Therefore, impedance matching can be achieved over a wide frequency band, and the input/output impedance and power distribution characteristics at all input/output terminals are good over a wide frequency band.

In the embodiment shown in FIG. 1, the impedance transformation between the center conductor of the coaxial line and the waveguide branching conductor plate is realized by a curved tapered impedance transformer 6. Similarly, broadband characteristics can be achieved by using a linearly tapered impedance transformer 6 as in the embodiment shown.

Furthermore, as in the embodiments shown in FIGS. 5 and 6, a wide band can be similarly achieved by performing stepwise impedance transformation using a stepwise impedance transformer 6.

7 to 11 show an impedance transformer 76 with a curved smooth taper shown in the embodiment of FIG. 1.
2 shows other modified examples of . In addition, impedance conversion can be performed using Tch as well as general impedance conversion.
It may also be realized by an ebysheH III number or the like.

As mentioned above, according to the present invention, impedance matching between the coaxial line and the waveguide can be achieved over a wide frequency band with an extremely simple configuration, so that the power distribution characteristics can be improved. This has the effect of providing a wide band.

[Brief explanation of the drawing]

FIGS. 1 to 11 are views showing each embodiment of the present invention, and FIG. 12 is a perspective view including a partially broken surface explaining the prior art.
Figure 13 is a cross-sectional view of the coaxial line, Figure 14 is a cross-sectional view of the waveguide,
FIG. 15 is an equivalent circuit diagram seen from the center conductor terminal of the coaxial line. Explanation of symbols of main parts 1... Rectangular waveguide 2... Coaxial line center conductor 4... Coaxial line outer conductor 5... Conductor plate

Claims (1)

[Claims] A rectangular waveguide, a conductor plate provided parallel to the H-plane of the waveguide to divide the inside of the rectangular waveguide, and an outer conductor connected to the E-plane of the waveguide and a center conductor. A power distribution circuit comprising a coaxial line connected to the conductor plate, the power distribution circuit comprising an impedance transformer at a connection portion between the center conductor of the coaxial line and the conductor plate.