JP2000278010A - Power combiner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power combiner where its replacement is not required in the case of changing the number of combined signals and no line interruption or the like is caused. SOLUTION: A combination point combining other ends of transmission lines 1a-1d connected respectively to output terminals of power amplifiers 3a-3d in this power combiner is provided with an impedance conversion section 2, coaxial cables 4A, 4B, 5A, 5B whose length is variable are connected to the impedance conversion section 2 to correct a loss of the impedance conversion section 2 due to mismatching by changing the length of the coaxial cables thereby allowing one set of the power combiner to cope with an optional number of combined powers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power combiner that enables an arbitrary number of composites with one combiner.

[0002]

2. Description of the Related Art Conventionally, in order to change the number of synthesized power amplifiers, it was necessary to convert the number of power amplifiers into a number of synthesizers corresponding to the number of synthesized power amplifiers.
For example, two combiners are required to combine two power combiners, and four combiners are required to combine four power combiners.

[0003]

As described above, in order to change the number of composites, it is necessary to convert the synthesizer according to the number of composites, and at that time, the line or the like is disconnected during the conversion. Problem.

[0004] The present invention has been made in view of the above points, and has as its object to provide a power combiner that does not require replacement work of the combiner when changing the number of combined circuits and does not break the line or the like. It is assumed that.

[0005]

In the power combiner according to the present invention, an impedance conversion unit is provided at a combining point obtained by combining the other ends of a plurality of transmission lines connected to the output terminals of a plurality of power amplifiers. In addition, a coaxial cable having a variable length is connected to the impedance conversion unit.

[0006]

FIG. 1 is a block diagram showing a basic circuit of a power combiner according to the present invention, in which an impedance converter is provided in a Wilkinson combiner for increasing saturation power and providing redundancy. Things. In FIG. 1, 1a to 1d denote characteristic impedance Z0 and length λ.
/ 2 transmission line, which is open at the combining point when the input side is open. Reference numeral 2 denotes an impedance conversion unit based on Q match selection, which converts the impedance at the combining point into a characteristic impedance of 50Ω. 3a to 3d show power amplifiers.

FIG. 2 is a diagram showing impedance conversion by Q match selection by the impedance converter 2. In this example, the impedance of 12.5Ω is converted to 50Ω by a transmission line of Z = √ (12.5 × 50) = 25Ω and λ / 4.
Generally known.

In FIG. 1, power amplifiers 3a, 3b and 3c are connected to inputs a, b and c, respectively, and input d is open. At this time, the impedance at the combined point is that input d is open. 50/3 ≒ 1
6.7Ω. The impedance at this synthesis point is impedance-converted to 50Ω by the impedance conversion unit 2, and the outputs of the power amplifiers 3a, 3b, and 3c are synthesized into three.

Therefore, by using the above-described power combiner, the number of power amplifiers can be arbitrarily changed from 2 to 4 without replacing the combiner, and the line break at that time is eliminated.

However, in the above-described power combiner, 2
In the case of combining and combining 4, the impedance conversion unit 2 has
Since the impedance is fixed at the best characteristic impedance in the combination, some mismatch loss occurs.

FIG. 3 is a block diagram showing a configuration of a power combiner for eliminating the above-described mismatch loss. In FIG. 3, the same portions as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. As a new code, 4A and 4B are coaxial cables having a characteristic impedance of 50Ω, one end of which is connected to both ends of the impedance conversion unit 2 and the other end of which is connected to a connector such as a front panel (not shown) of the power combiner. . 5A and 5B are coaxial cables having the same characteristic impedance of 50Ω as the coaxial cables 4A and 4B. One end is a connector such as a front panel (not shown) of the power combiner, and the other end is open.

In the case of the configuration shown in FIG.
In the case of combining 2 and 4, the mismatch loss occurs because the impedance conversion unit 2 is fixed. However, in the configuration shown in FIG. 3, the mismatch loss of the impedance conversion unit 2 is corrected by exchanging the coaxial cables 5A and 5B. However, the best synthesis can be realized in each synthesis. By the way, the best combination can be realized by omitting the coaxial cables 5A and 5B at the time of combination of the three.

One end of each of the coaxial cables 5A and 5B can be easily connected to a connector of the coaxial cables 4A and 4B on a front panel or the like. Also, coaxial cables 5A, 5B
May be opened or short-circuited by changing the length. Further, by changing the impedance converter 2 and the coaxial cables 5A and 5B, it is possible to cope with an arbitrary combined number.

FIGS. 4 to 8 are characteristic diagrams showing the simulation results of the loss at each number of composites in the present invention and the conventional example. FIG. 4 shows the loss in the two composites of the present invention, and FIG. Loss in 3 synthesis, FIG. 6 shows loss in 4 synthesis of the present invention, FIG.
FIG. 8 shows the loss in the four synthesis of the conventional example, and FIG. 8 shows the loss in the four synthesis, respectively. The table below shows the difference between the loss in the conventional example and the loss in the present invention (frequency is 2160 MH).
z).

[0015]

[Table 1]

As can be seen from the table, it is understood that the loss is not so different in the two synthesis, but the loss is remarkably smaller in the four synthesis in the present invention.

Therefore, according to the above-described embodiment, the coaxial cables 4A, 4B and 5
By connecting A and 5B and changing the length of the coaxial cable, it is possible to obtain a power combiner capable of coping with an arbitrary number of composites with one combiner, and combining the arbitrary number of composites with one combiner. And can be realized with low loss, and there is no disconnection when changing the number of composites.

[0018]

As described above, according to the present invention, the impedance conversion unit is provided at the combining point obtained by combining the other ends of the plurality of transmission lines respectively connected to the output terminals of the plurality of power amplifiers. Since a coaxial cable with a variable length is connected to the impedance conversion unit, there is no need to replace the synthesizer when changing the number of composites, so there is no break in the line, etc. , The mismatch loss of the impedance conversion unit can be corrected, and a power combiner that can handle an arbitrary number of composites with one combiner can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic circuit of the present invention.

FIG. 2 is an explanatory diagram showing an impedance conversion unit using a Q match section.

FIG. 3 is a block diagram illustrating a configuration of a power combiner according to the embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a simulation result of a loss at two composite numbers in the present invention.

FIG. 5 is a characteristic diagram showing a simulation result of loss at three combined numbers in the present invention.

FIG. 6 is a characteristic diagram showing a simulation result of a loss at four combined numbers in the present invention.

FIG. 7 is a characteristic diagram showing a simulation result of a loss at two composite numbers in a conventional example.

FIG. 8 is a characteristic diagram showing a simulation result of a loss at four combined numbers in a conventional example.

[Explanation of symbols]

 1a to 1d Transmission line 2 Impedance converter 3a to 3d Power amplifier 4A, 4B, 5A, 5B Coaxial cable

Claims (1)

[Claims] An impedance converter is provided at a combining point obtained by combining the other ends of a plurality of transmission lines connected to the output terminals of a plurality of power amplifiers, and the length of the impedance converter is made variable. A power combiner characterized by connecting a coaxial cable.