JPH0117601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in waveguide type power dividers used in microwave bands and millimeter wave bands.

FIG. 1a is a perspective view showing an example of a conventional rectangular waveguide type power divider, and FIG. 1b is a sectional view of the power divider shown in FIG. 1a in the tube axis direction. In Figure 1a, 1 is the main waveguide, 2 is the sub waveguide A, 3
is sub-waveguide B, 4 is sub-waveguide A2 and sub-waveguide B3.
This is a thin conductive plate to separate the

In FIG. 1, the conductor plate 4 is provided perpendicularly to the electric field of the fundamental mode propagating within the main waveguide 1 and so as to divide the height of the main waveguide 1 into two equal parts. Therefore, if the conductor plate 4 is extremely thin, the fundamental mode incident on the main waveguide 1 is not affected by the conductor plate 4 and is equally divided into the sub-waveguide A2 and the sub-waveguide B3.

At this time, a tube wall current of the TE ₁₀ mode wave (fundamental mode wave) flows through each waveguide as shown by the solid arrow in Figure 1b, and the amplitude of the current is the same on both the front and back sides of the conductor plate 4. Since the phases are opposite, if the conductor plate 4 is thin, no current will equivalently flow.

However, in the power divider shown in FIG. 1, if there is a fundamental mode reflected wave in one of the sub-waveguides, for example, this fundamental mode reflected wave will be transmitted between the main waveguide 1 and the sub-waveguides A2 and B3. At the boundary, it is converted into higher-order modes TE _1o and TM _1o (n=1, 2, . . . ). These modes are non-propagating modes,
It does not propagate to the main waveguide 1, but is completely reflected in the sub-waveguide A2 and sub-waveguide B3, is reconverted to the fundamental mode of the sub-waveguide, and propagates in the sub-waveguides A2 and B3. . That is, if there is a reflected wave in one of the sub-waveguides, there is a problem in that coupling occurs between the sub-waveguides.

For this reason, the conventional power divider has a structure in which a resistor plate 5 is provided at the tip of a conductor plate 4, as shown in FIG. As a result of the above-described coupling between the sub-waveguides, among the fundamental modes propagating through both sub-waveguides, the one caused by the reflected wave has an opposite phase between sub-waveguide A2 and sub-waveguide B3. , the amplitude and phase of the current flowing on both sides of the conductor plate 4 are no longer equal amplitude and opposite phase, and the conductor plate 4
Even if the conductor plate 4 is thin, an unbalanced current occurs in a certain direction on the conductor plate 4. As described above, since no unbalanced current flows when there is no coupling, this unbalanced current indicates that there is coupling between the sub-waveguides, that is, it indicates an unnecessary fundamental mode component due to reflected waves. If this unbalanced current is absorbed by the resistor plate 5, unnecessary components can be reduced and the coupling between the sub-waveguides can be substantially reduced.

However, in the conventional power divider, it is necessary to lengthen the resistor plate 5 in order to reduce the coupling between the sub-waveguides, and there is a problem in that the loss of the power divider for the fundamental mode is large.

In order to solve this problem, patent application No. 55-034587
proposes installing a resistor plate at a position approximately 1/4 of the tube wavelength from the tip of the conductor plate.

This is because, as a result of the above-mentioned coupling, the unbalanced current generated by the reflected wave is maximized, but assuming that the position is 1/4 of the pipe wavelength from the tip of the conductor plate 4, the unbalanced current at this position is It is designed to absorb equilibrium current. However, when the above-mentioned coupling occurs, the non-propagating mode waves generated at the boundary between the main waveguide 1 and the sub-waveguides A2 and B3 are completely destroyed at the boundary due to the influence of the susceptance determined by the non-propagating mode. It is not reflected, but is completely reflected at a position slightly closer to the main waveguide 1 from the tip of the conductor plate 4. For this reason, the unbalanced current generated by the reflected wave does not reach its maximum at a position approximately 1/4 of the wavelength in the tube from the tip of the conductor plate 4, resulting in the problem that the coupling between the sub-waveguides cannot be made sufficiently small. It was hot.

In order to eliminate these drawbacks, this invention provides a coupling hole perpendicular to the tube axis direction with a length of approximately 1/2 wavelength of the free space wavelength at a position less than 1/4 of the tube wavelength from the tip of the conductor plate. In addition, a resistor is attached to a part or all of the coupling hole, and the drawings will be described in detail below.

FIG. 3a is a perspective view of a power divider showing an embodiment of the present invention, and FIG. 3b is a sectional view of the power divider shown in FIG. 3a. 1 to 4 are the same as those in FIG. 1, 6 is a coupling hole, and 7 is a resistance plate attached to coupling hole 6. The dashed arrow in FIG. 3b indicates the unbalanced current caused by the reflected wave from one of the sub-waveguides.

In the power divider of the present invention, the fundamental mode incident on the main waveguide 1 does not generate a current in the conductor plate 4 as described above, so it is not affected by the coupling hole 6 and passes through the sub waveguides A2 and B3. It is divided into two equal parts. When there is a reflected wave in one of the sub-waveguides, the wave becomes a non-propagating mode in the main waveguide 1 as described above, and coupling occurs between the sub-waveguides. In order to reduce this coupling, the unbalanced current generated by the reflected wave may be absorbed. If this resistor plate is too large, it will increase the size of the power divider and cause fundamental mode loss, so it is best to partially install this resistor plate at the position where the unbalanced current is maximum. It is an absorption method. As mentioned above, the sub waveguides A2, B3,
As can be easily inferred from the fact that when the currents on the conductor plate 4 are excited in the same phase, the current on the conductor plate 4 becomes out-of-phase, canceled out, and does not flow. This is a case where the tube wall currents on the conductor plate 4 due to the excitation of the sub-waveguides A2 and B3 are superimposed in the same direction, that is, a case where the sub-waveguides A2 and B3 are excited in opposite phases. At this time, a resistance plate may be provided at a position where the unbalanced current is maximum.

An equivalent circuit when the sub-waveguides A2 and B3 are excited in opposite phases is shown in FIG.

As shown in FIG. 4, the sub-waveguides A2 and B3 become lines terminated with the capacitive susceptance _B1 determined by the non-propagating mode as described above. If this susceptance B ₁ is ignored, the unbalanced current flowing through the conductor plate 4 in the tube axis direction reaches its maximum at a position 1/4 of the tube wavelength from the tip of the conductor plate 4. However, due to the influence of the susceptance _B1 , the maximum point of the unbalanced current changes and becomes a position less than 1/4 of the tube wavelength from the tip of the conductor plate 4. Further, the binding hole 6 exhibits a susceptance _B2 determined by the size of the binding hole 6. Therefore, the coupling hole 6 is placed at a position where the unbalanced current in the tube axis direction is maximum when the sub-waveguides A2 and B3 are excited in opposite phases, and the size of the coupling hole 6 is adjusted so that the susceptance _B2 becomes zero. The length is approximately 1/2 of the free space wavelength, and the resistance R
If the resistance value of is set to the optimum value, even if the length of the resistance plate 7 in the tube axis direction is short, it is possible to effectively absorb the unbalanced current generated by the reflected wave, thereby reducing the coupling between the sub-waveguides. Can be done.

FIG. 5 is a graph showing coupling characteristics between sub-waveguides in the power divider having the structure shown in FIG. The coupling between the sub-waveguides is extremely small, approximately -30 dB or less.

Further, in this power divider, since the length of the resistance plate 7 in the tube axis direction is short, there is an advantage that power loss in the fundamental mode is small.

Although the case of a rectangular waveguide has been described above, the present invention is not limited to this and may be applied to waveguides of other shapes such as a circular waveguide. Further, although the case where a resistance plate is used as the resistor has been described, the present invention may also be applied to a case where a chip resistor or the like is used.

As described above, in the waveguide type power divider according to the present invention, coupling holes having a length of approximately 1/2 wavelength of the free space wavelength and perpendicular to the tube axis direction are formed in the conductor plate that partitions the sub waveguides. Install the two sub-waveguides at the position where the current flowing through the conductor plate is maximum when the two sub-waveguides are excited in opposite phase at less than 1/4 of the tube wavelength from the tip of the conductor plate, and place a resistor in part or all of the coupling hole. By providing the waveguide on the same surface as the conductor plate, there is an advantage that the coupling between the sub-waveguides is small and a power divider with low loss can be obtained.

[Brief explanation of drawings]

Figure 1a is a perspective view of a conventional rectangular waveguide power divider, Figure 1b is a sectional view thereof, and Figure 2 is a perspective view of a conventional rectangular waveguide power divider provided with a resistor plate. ,
FIG. 3a is a perspective view of a rectangular waveguide type power divider according to an embodiment of the present invention, FIG. 3b is a sectional view thereof, and FIG.
The figure is a diagram for explaining the operation of the power divider of the present invention, and FIG. 5 is a diagram showing the coupling characteristics between sub-waveguides when the present invention is implemented. In the figure, 1 is the main waveguide, 2 is the sub-waveguide A, 3 is the sub-waveguide B, 4 is the conductor plate, 5 is the resistor plate, 6 is the coupling hole, and 7 is installed in the coupling hole 6. resistor plate,
B ₁ and B ₂ are susceptances, and R is resistance. In addition,
In the drawings, the same or corresponding parts are given the same reference numerals.

Claims (1)

[Claims] 1 In a waveguide type power divider that distributes power to two sub-waveguides in which a conductor plate is provided in a direction perpendicular to the direction of the electric field in the main waveguide, the conductor plate has an outline of the free space wavelength. A coupling hole having a length of 1/2 and perpendicular to the tube axis direction is formed in the conductor plate when the two sub-waveguides are excited in opposite phase from the tip of the conductor plate at 1/4 or less of the tube wavelength. A waveguide type power divider, characterized in that the waveguide type power divider is provided at a position where the current flowing in the tube axis direction is maximum, and a resistor is provided in a part or all of the coupling hole on the same surface as the conductor plate.