JPH0562845B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a power amplification device, and in particular, to a power amplification device that distributes high-frequency power to a plurality of outputs and individually controls amplifiers provided in each branch path. The present invention relates to a power amplifier device that does not reduce impedance matching and improves reliability by combining power.

[Conventional technology]

For example, transponders installed on aircraft,
Alternatively, in the ground radar transmitter facing these, the transmission power is frequently increased or decreased depending on the distance to the exploration target aircraft.

Conventionally, as a transmission power control device, the device shown in Fig. 6A,
There is something shown in b.

FIG. 6A shows an amplifier 1 that amplifies the high frequency signal from the input side A, and is connected to the output end of the amplifier 1.
It is composed of a variable attenuator 2 that attenuates the output of the amplifier 1, and a control section 3 that controls the amount of attenuation of the variable attenuator 2.

In the above configuration, the input power is once amplified by the amplifier, then attenuated to a desired amount by the variable attenuator 2, and output to the B side.

Figure 6b shows an amplifier 1' that amplifies the high frequency signal.
and a variable power supply 4 that increases or decreases the power supply voltage of the amplifier 1'.
It consists of

In the above configuration, the predetermined amount of power that has entered the amplifier 1' can be adjusted by the variable power source 4 to change the saturation level in the amplifier 1' to obtain a desired output power.

[Problem that the invention seeks to solve]

However, in the conventional power control device shown in Fig. 6A, the power once amplified to the maximum is wasted in the attenuator, which not only causes large losses and is uneconomical, but also requires heat dissipation. This has the drawback of increasing the size of the device.

In addition, in the electric power control device shown in Figure 6B, since the power supply voltage of the amplifier is changed, the input impedance changes, so there is a drawback that operation is unstable due to impedance mismatch or unnecessary waves are generated. . Especially for products that require strict standards such as aircraft transponders,
Impossible to use.

[Means and actions for solving problems]

The present invention has been made in view of the above, and in order to improve impedance matching without causing energy loss or increasing the size of the device, and to increase reliability of the device, a divider is provided between the input and output of a plurality of power amplifiers. and a coupler, and selectively drives a required number of the plurality of power amplifiers to obtain a desired combined power.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power amplifier according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating the principle of the present invention, which includes a distributor 5 that distributes input high frequency power Pin to a plurality of devices, and an output terminal of the distributor 5 connected to its input terminal. The output terminals of the power amplifier 6 and the n power amplifiers 6 supply power to the coupler 8 and the n power amplifiers 6 connected to their input terminals.
It is composed of a switching section 10 that turns on and off the application of Vec, and a control section 9 that controls the operation of the switching section 10.

For the distributor 5 and the coupler 8, for example, a multi-terminal Wilkinson type, a 90° hybrid coupler type, or a branch line coupler type is used in which the input connections are reversed.

In Figure 2, four power amplifiers 6 with a gain of 10 dB are used in the divider 5 and combiner 8 as shown in Figure 3 A and B.
It is constructed by connecting three 90° hybrid couplers 11.

Figures 3A and 3B are examples of a 3dB90° hybrid coupler, and Figure 3A shows its structure, with the upper and lower patterns 13a and 13b of the strip lines printed on the Teflon base 12, respectively. It is formed between the surfaces of the metal ground 14. The length l is 1/4 of the wavelength λ of the center frequency, and the coupling is performed between the patterns on the top and bottom surfaces,
It is three-dimensionally small. Figure 3B shows an equivalent circuit of the signal flow in power distribution.If there is no insertion loss, the voltage applied to the terminal,
For each half of the input terminal (=-3dB), an output with a phase difference of 90° is generated. Therefore, it is necessary to consider the phase difference between the divider 5 and combiner 8 and combine them so that they are opposite to each other, so that the input and output of this power amplifier are out of phase by 180 degrees. It becomes something.

The operation of the above configuration will be explained. The high-frequency power Pin input to the distributor 5 is distributed to n components while satisfying the input/output impedance (in the case of FIG. 2, the power is distributed to 4 components by the 90° hybrid coupler 11), and each is divided into a power amplifier. 6
After being subjected to the required power amplification, the input power is similarly applied to the coupler 8 with impedance matching.
are combined into one electric power by

At this time, the switching section 10 controlled by the control section 9
Therefore, by arbitrarily selecting and supplying the power to the power amplifier 6, the amount of power combined into one can be arbitrarily controlled. In other words, if power is supplied to the required one from among multiple power amplifiers, the power will be increased in stages compared to the case where power is supplied to all of the multiple power amplifiers.
The combined power amount is small and can be reduced to a desired power by arbitrarily setting the number to be selected.

In the above embodiments, the power amplifiers used have the same gain, but in implementing the present invention, it is not necessary to be limited to this, and it is possible to combine power amplifiers of various sizes. It becomes possible to control the output level more precisely.

Furthermore, the control method for the power amplifier is not limited to simply connecting and disconnecting the power supply, but may also include means for changing the power supply voltage value, and in this way, control close to stepless adjustment can be performed.

If the output power is controlled by the method described above, since the divider and combiner are provided, the impedance fluctuation of the power amplifier itself located between them will directly affect the external device. Less impact.

Furthermore, since it is equipped with multiple power amplifiers, even if a problem occurs such as damage to some of the power amplifiers, the remaining ones can make up for it, making it especially suitable for aircraft, etc., which require high reliability. It is most suitable for what is being done.

Furthermore, it is generally difficult and expensive to obtain a high output with one power amplifier, but if configured as in the present invention, a relatively small output is sufficient and is economical. .

In the above embodiment, a 90° hybrid coupler was used for the distributor and coupler, but the present invention is not limited to this, and for example, a 3 dB
A branch line Kapra Wilkinson method may also be used. Figure 4A shows its structure, which is composed of microstrip lines or strip lines printed on a substrate (not shown).
The length l is 1/4 of the wavelength λ of the center frequency. Fourth
Figure B shows the equivalent circuit in power distribution. When the power of 0 dBm is applied to level terminal,
-3dB is generated between the terminals, and there is a phase difference of 90° between the terminals.

FIG. 5 shows the configuration of the Wilkinson type input terminal. The structure consists of microstriplines or striplines and isolation resistors printed on a substrate (not shown).
The length l is the wavelength 1/4 of the center frequency λ. The phase is
They are in the same phase.

〔Effect of the invention〕

As described above, according to the power amplification device according to the present invention, a divider and a coupler are arranged at the input and output of a plurality of power amplifiers, and a required number of the plurality of power amplifiers are selectively driven. In order to obtain the desired combined power, it is possible to improve impedance matching and increase the reliability of the device without increasing the size of the energy loss device.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the principle of an embodiment of the invention, Fig. 2 is a block diagram showing a specific embodiment of the present invention, Fig. 3 A and B, and Fig. 4 A and B. ,
FIG. 5 is an explanatory diagram showing an example of a distributor and a combiner;
FIGS. 6A and 6B are block diagrams showing a conventional power amplifier. Explanation of symbols 5...Distributor, 6...Power amplifier, 8...Coupler, 9...Control section, 10...Switching section, 11...90° hybrid coupler.

Claims (1)

[Claims] 1. A power divider having a single input terminal and a plurality of output terminals, a power divider having a plurality of input terminals and a single output terminal, and a plurality of output terminals of the power divider. and a plurality of power amplifying means respectively connected between the plurality of input terminals of the power combiner, and a switching means for selectively turning on and off DC power supplied to each of the plurality of power means. A power amplifying device characterized in that it is configured to control the amount of power outputted from a single output terminal of the power combiner in stages. 2. The power amplification device according to claim 1, wherein the amplification degrees of some of the plurality of power amplification means are different from each other.