JP2011135232A - Power combiner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly efficiently combine powers by reducing power loss. <P>SOLUTION: A power combiner combines in phase a plurality of high frequency powers to be individually input from a plurality of input ports 1-4 and outputs the combined power from an output port, and includes: a plurality of input side transformers T1, T2 for combining a plurality of high frequency powers every two inputs; and a plurality of output side transformers T4, T5 for connecting the respective outputs of the input side transformers T1, T2 to the primary sides, serially connecting the secondary sides to the output port, and simultaneously performing the combination and impedance conversion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power combiner that combines power amplifier outputs, for example.

  For example, a technique disclosed in Patent Document 1 has been proposed as a power distribution / combining device that distributes or combines microwave high-frequency power used in communication equipment and the like. When this power distribution synthesizer is used as a power synthesizer, for example, signals output from a plurality of power amplifiers are respectively input, and these powers are combined and output.

Japanese Patent Application Laid-Open No. 7-142953

  By the way, as a problem when the above power distribution combiner is used as a power combiner, first, there is a large power loss due to current combining. Another problem is stray capacitance and stray inductance. In a high-frequency circuit, stray capacitance and stray inductance are generated by transmission lines and circuit elements, affecting circuit impedance.

  The present invention has been made paying attention to the above circumstances, and it is an object of the present invention to provide a power combiner capable of reducing power loss and performing power combining with high efficiency.

  In order to achieve the above object, one aspect of the present invention is a power combiner that combines a plurality of high-frequency powers individually input from a plurality of input ports in the same phase and outputs the power from an output port, the plurality of high-frequency powers A plurality of input-side transformers that combine power every two inputs, and outputs of the plurality of input-side transformers are connected to the primary side, and a secondary side is connected in series to the output port to combine and change impedance There is provided a power combiner including a plurality of output-side transformers that simultaneously perform the above.

  That is, according to the present invention, it is possible to provide a power combiner that can reduce power loss and perform power combining with high efficiency.

The circuit block diagram which shows one Embodiment of the electric power combiner which concerns on this invention. FIG. 2 is an operation explanatory diagram of the circuit of FIG. 1. The circuit block diagram which shows an example of the conventional electric power combiner. FIG. 4 is an operation explanatory diagram of the circuit of FIG. 3.

Embodiments according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a circuit configuration diagram showing an embodiment of a power combiner according to the present invention. In FIG. 1, the high-frequency power signals input from the input ports 1 to 4 are combined in the same phase by the transformers T1 and T2 on the input side every two inputs and output. The signals synthesized by the transformers T1 and T2 are distributed from the transformer T3 to the primary side of the transformers T4 and T5, respectively. The transformers T4 and T5 on the output side are connected in series on the secondary side, and simultaneously perform the synthesis of the distributed signals and the impedance conversion.

  For example, if the impedances of the input ports 1 to 4 and the output port are all 50Ω, the power input from the input ports 1 to 4 is synthesized by T1 to T5 and output from the output port. At this time, by selecting 100Ω for the unbalanced absorption resistors R1 and R2 and 50Ω for R3, all impedances seen from the input ports 1 to 4 are 50Ω even when the power of the input ports 1 to 4 varies. Thus, isolation can be obtained between the input ports 1 to 4. For example, when the power of the input port 1 becomes 0, 1/2 of the current from the input port 2 flows to the transformer T1 through R1, so the input current of T1 is balanced. Also, the input current of the transformer T3 is added to the output current of the T1 through R3 by adding 1/4 of the output current of the transformer T2, and flows to the transformer T3, so that the input current can be balanced in the same manner as the transformers T1 and T2.

FIG. 2 is an operation explanatory diagram of this circuit. Assuming that the impedance of all the input ports 1 to 4 is Z and the current is I, the impedance Z and current I at the points (a) to (d) in FIG. 2 are as follows.
(A) ... Z / 2, 2I
(B) ... Z / 2, 2I
(C) ... Z / 2, 2I
(D) ... Z / 2, 2I
That is, since the output of the transformer T3 is not synthesized, the impedance Z at the points (c) and (d) in FIG. 2 remains Z / 2 and the current remains 2I. Here, assuming that the impedance ratio of T4 and T5 is 1: 1, the impedance Z / 2 on each transformer primary side is connected in series on the secondary side, and the output impedance is the same as the input Z. Further, as described above, when viewed from the input ports 1 to 4, it is possible to take isolation between the input ports 1 to 4.

  Here, for comparison, FIG. 3 shows an example of a conventional power combiner. In the conventional circuit, the configuration from each of the input ports 1 to 4 to the transformer T3 is the same as that of the circuit of FIG. 1, but after the current is synthesized by the transformer T3, impedance conversion is performed by the transformer T4.

FIG. 4 is an operation explanatory diagram of this conventional circuit. In FIG. 4, when the impedance of each of the input ports 1 to 4 is Z and the current is I, the impedance Z and current I at the points (a) to (c) in the figure are as follows.
(A) ... Z / 2, 2I
(B) ... Z / 2, 2I
(C) ... Z / 4, 4I
As a problem of this combining method, taking FIG. 3 as an example, first, there is a large power loss due to current combining. In particular, at point (c), a current four times as large as that of each of the input ports 1 to 4 flows between T3 and T4, resulting in a large transmission loss between T3 and T4. For this reason, the transmission line must be made thick, and T4 itself needs a large element.

  Another problem is stray capacitance and stray inductance. In a high-frequency circuit, stray capacitance and stray inductance are generated by transmission lines and circuit elements, affecting circuit impedance. This corresponds to an imaginary component in the complex impedance. This imaginary component is not so much affected when it is present at a high impedance, for example, the input port of FIG. 2, but the components present at the portion where the impedance is low as at (c) are input ports 1-4. When viewed from the output port, the value is quadrupled, which greatly affects the input / output impedance.

  On the other hand, in the present embodiment, the output impedance is Z / 4 with respect to the input impedance Z, so that the output impedance is Z / 2 so that the output side transformer is connected in two stages. . In FIG. 1, the configuration from each of the input ports 1 to 4 to the transformer T3 is the same as that of the conventional circuit of FIG. In the conventional circuit, after the current is synthesized by the transformer T3, impedance conversion is performed by T4. However, in the circuit of this embodiment, synthesis is not performed by the output of the transformer T3, and synthesis and impedance conversion are performed by the transformers T4 and T5 on the output side. It is the composition of impedance (voltage) composition which performs simultaneously.

  That is, according to the present embodiment, power combining can be performed with high efficiency without greatly reducing the impedance of the circuit as compared with the conventional case. For example, when the impedance is halved, the flowing current is doubled, but the power loss is quadrupled. Therefore, when the conventional circuit of FIG. 4 is compared with the circuit of this embodiment of FIG. Since the power loss during T5) is ¼ that of the prior art, a small element can be used for the transmission line and T4 (T5). Further, since the circuit impedance does not decrease as compared with the conventional case, the influence of the imaginary component of the complex impedance generated between T3 and T4 can be reduced, and the matching adjustment of the input / output ports is facilitated.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  1, 2, 3, 4... Input port, T1, T2, T3, T4... Transformer, R1, R2, R3.

Claims (1)

A power combiner that combines a plurality of high-frequency powers individually input from a plurality of input ports in the same phase and outputs from the output port,
A plurality of input-side transformers that combine the plurality of high-frequency powers every two inputs;
A plurality of output-side transformers that simultaneously perform synthesis and impedance conversion by connecting each output of the plurality of input-side transformers to a primary side and connecting a secondary side in series to the output port; A power combiner.

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