JP2881043B2 - High frequency linear amplifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency linear amplifier having good distortion characteristics used for mobile communication and satellite communication using a digital modulation method.

[0002]

Description of the Prior Art FIG. 10 is, for example, "high-frequency transistors data
Nonlinear element "using, patent publications, is a block diagram of a conventional radio frequency linear amplifier shown in flat 2-51287, 1 is an input terminal in FIG, 2 is an output terminal, 19 is a directional coupler, 20 Impedance adjustment circuit, 21 is an amplifier, 2
2 is a matched load, 23 is the first terminal of the directional coupler, 24
Is the second terminal of the directional coupler.

Next, the operation will be described. A part of the signal input from the input terminal 1 is extracted by the directional coupler 19 and consumed by the matching load 22 connected to the second terminal 24, but the remaining part is input to the amplifier 21. Amplifier 21
A part of the signal reflected by is extracted by the directional coupler 19 and enters the impedance adjustment circuit 20 connected to the first terminal 23. This signal is divided into a signal which enters the matching load 22 and is consumed, and a signal which is taken out again by the directional coupler 19 and returns to the amplifier 21.

As described above, by adjusting the impedance adjustment circuit 20 and adjusting the signal returned to the amplifier 21, the signal source impedance from the amplifier 21 to the input terminal 1 side can be adjusted. The dominant reflected wave at the input terminal 1 is a signal reflected by the amplifier 21 and returned to the input terminal 1 without being taken out by the directional coupler 19. The change in the reflection characteristics at is small.

On the output side, the impedance adjustment circuit 20 is adjusted according to the same principle, so that the output terminal 2
Can be adjusted without significantly changing the reflection characteristics of the amplifier 21 at the output terminal 2 side from the amplifier 21.

AM-PM of high-frequency transistor amplifier circuit
It is known that the conversion characteristic depends on the circuit conditions of the amplifier circuit. With such a configuration, the input terminal 1 and the output terminal are adjusted by adjusting the coupling amount of the impedance adjustment circuit 20 and the directional coupler 19. 2, the signal source impedance characteristic and the load impedance characteristic can be adjusted so that the AM-PM conversion characteristic becomes good without greatly changing the reflection characteristic.

[0007]

Since the conventional high-frequency linear amplifier is configured as described above, when the amplifier is configured in a relatively low frequency band, the size of the directional coupler provided on the input side increases. As a result, there is a problem that the amplifier becomes large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a small size, an input reflection characteristic and A
An object is to obtain a high-frequency linear amplifier having a good M-PM conversion characteristic.

[0009]

According to the first aspect of the present invention,
A high-frequency linear amplifier is an input circuit for inputting a signal.
An active element circuit that processes signals input from a power circuit.
Outputs the signal processed by the active element circuit to the next circuit
In a high-frequency linear amplifier composed of an output circuit,
The input impedance of the active element circuit to the power circuit.
To convert to an impedance higher than the source impedance.
Impedance conversion circuit and the impedance conversion circuit
Connect a resistor to the active element circuit on the side opposite to the side to which the input is connected.
Connect and configure, the above power source impedance
The input impedance change of the active element circuit was connected as above
The impedance is returned to the power source impedance by a resistor.
The high-frequency linear amplifier according to the second aspect of the present invention includes the above-described resistor.
Is the active element circuit by the impedance conversion circuit.
It is connected between the side to be connected and the opposite side and the ground.

A high-frequency linear amplifier according to a third aspect of the present invention.
Means that the resistance is
Connect between the side to which the slave circuit is connected and the other side and the signal input terminal
It was done. High-frequency linear increase according to the invention of claim 4.
The width converter, the impedance conversion circuit was composed of passive elements
Things. High-frequency linear amplifier according to the invention of claim 5.
The impedance conversion circuit is composed of distributed constant lines
Things.

[0011]

In the first invention, when the signal source impedance for improving the AM-PM conversion characteristic is higher than the input impedance of the active circuit element, the impedance conversion circuit and the opposite side of the impedance conversion circuit from the active circuit element are used. The signal source impedance is set to AM-
Set and amplify PM conversion characteristics to be good
To see the active circuit element side from the input terminal of the device
Closer to the power supply impedance Rg. Further, in the second invention, when the signal source impedance for improving the AM-PM conversion characteristic is lower than the input impedance of the active circuit element, the impedance conversion circuit and the impedance conversion circuit are connected to the opposite side of the active circuit element. The AM-PM conversion characteristic of the signal source impedance is
Make sure that the settings are good and that the
From the power supply impedance
-Close to dance Rg.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a configuration diagram in the case where the signal source impedance at which the AM-PM conversion characteristic is good is higher than the input impedance of the FET. In FIG. 1, 3 is an FET, 4 is a first impedance conversion circuit, 5 is a parallel resistor, 6 Is an output matching circuit. Input impedance of the FET3 by first impedance conversion circuit 4, is converted into a temporarily higher impedance than the source impedance Rg, source impedance by the parallel resistor 5 provided FET3 opposite side of the first impedance conversion circuit 4 It is returned near Rg.

In this circuit configuration, the input terminal 1 is connected to the FET
The reflection characteristic that sees the side is good, and the signal source impedance that sees the input side from the FET 4 is higher than the input impedance of the FET 4. When the signal source impedance at which the AM-PM conversion characteristic becomes good is higher than the input impedance of the FET 3, the AM-PM conversion characteristic of the amplifier becomes good.

Next, an embodiment of the second invention will be described with reference to the drawings. FIG. 2 is a configuration diagram in the case where the signal source impedance at which the AM-PM conversion characteristic is good is lower than the input impedance of the FET. In FIG. 2, reference numeral 7 denotes a second impedance conversion circuit, and reference numeral 8 denotes a series resistor. The input impedance of the FET 3 is temporarily converted to an impedance lower than the power supply impedance Rg by the second impedance conversion circuit 7, and is near the power supply impedance Rg by the series resistor 8 provided on the opposite side of the impedance conversion circuit 7 from the FET 3. Will be returned.

In this circuit configuration, the input terminal 1 is connected to the FET
The reflection characteristic that sees the side is good, and the signal source impedance that sees the input from FET3 is lower than the input impedance of FET3. When the signal source impedance at which the AM-PM conversion characteristic becomes good is lower than the input impedance of the FET 3, the AM-PM conversion characteristic of the amplifier becomes good.

In the prior art, the signal source impedance for improving the AM-PM conversion characteristics is not specified, and when the AM-PM conversion characteristics are improved, the input reflection characteristics cannot always be improved. Absent. However, when the configuration of the present invention is used, the reflection characteristic at the input terminal 1 can be improved and the AM-PM conversion characteristic can be improved at the same time whether the impedance is higher or lower than the input impedance of the FET. .

In the high-frequency linear amplifier according to the present invention, while improving the reflection characteristics from the input terminal 1 to the FET side, the F
Mismatch occurs at the gate terminal portion of the ET, and the signal source impedance is set so as to improve the AM-PM conversion characteristics.

Embodiment 3 FIG. FIG. 3 is a circuit diagram of a linear amplifier according to another embodiment of the present invention. In FIG. 3, reference numeral 9 denotes a low-pass filter type impedance conversion circuit, and reference numeral 5 denotes a parallel resistor.

Embodiment 4 FIG. FIG. 4 is a circuit diagram of a linear amplifier according to another embodiment of the present invention. In FIG. 4, reference numeral 9 denotes a low-pass filter type impedance conversion circuit, and reference numeral 8 denotes a series resistor.

Embodiment 5 FIG. FIG. 5 is a circuit diagram of a linear amplifier according to another embodiment of the present invention. In FIG. 5, reference numeral 10 denotes a high-filter impedance conversion circuit, and reference numeral 5 denotes a parallel resistor.

Embodiment 6 FIG. FIG. 6 is a circuit diagram of a linear amplifier according to another embodiment of the present invention. In FIG. 6, reference numeral 10 denotes a high-filter impedance conversion circuit, and reference numeral 8 denotes a series resistor.

Embodiment 7 FIG. FIG. 7 is a circuit diagram of a linear amplifier according to another embodiment of the present invention. In FIG. 7, reference numeral 11 denotes a quarter wavelength distributed constant line type impedance conversion circuit, and reference numeral 5 denotes a parallel resistor.

Embodiment 8 FIG. FIG. 8 is a circuit diagram of a linear amplifier according to another embodiment of the present invention. Reference numeral 11 denotes a quarter wavelength distributed constant line type impedance conversion circuit, and reference numeral 8 denotes a series resistor.

Embodiment 9 FIG. FIG. 9 is a circuit diagram of a linear amplifier according to another embodiment of the present invention. In the figure, 12 is a first-stage amplifier, 13 is a second-stage amplifier, 14 is an input matching circuit of a third-stage amplifier, and 15 is 3
The first-stage FET 16 is an output matching circuit of the third-stage amplifier 17
Denotes an output matching circuit of the fourth stage FET and the 18th wave fourth stage amplifier. In this case, between the third and fourth stages, the conjugate impedance is matched with the power supply impedance Rg other than 50Ω.

[0025]

As described above, according to the present invention, it is possible to obtain a small-sized high-frequency linear amplifier having good input reflection characteristics and good AM-PM conversion characteristics.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a high-frequency linear amplifier according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a high-frequency linear amplifier according to another embodiment of the present invention.

FIG. 3 is a configuration diagram of a high-frequency linear amplifier according to another embodiment of the present invention.

FIG. 4 is a configuration diagram of a high-frequency linear amplifier according to another embodiment of the present invention.

FIG. 5 is a configuration diagram of a high-frequency linear amplifier according to another embodiment of the present invention.

FIG. 6 is a configuration diagram of a high-frequency linear amplifier according to another embodiment of the present invention.

FIG. 7 is a configuration diagram of a high-frequency linear amplifier according to another embodiment of the present invention.

FIG. 8 is a configuration diagram of a high-frequency linear amplifier according to another embodiment of the present invention.

FIG. 9 is a configuration diagram of a high-frequency linear amplifier according to another embodiment of the present invention.

FIG. 10 is a configuration diagram of a conventional high-frequency linear amplifier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input terminal 2 Output terminal 3 FET 4 1st impedance conversion circuit 5 Parallel resistance 7 2nd impedance conversion circuit 8 Series resistance

Continued on the front page (72) Inventor Yoji Isoda 5-1-1, Ofuna, Kamakura-shi, Kanagawa Prefecture Inside the Electronic Systems Research Laboratories, Mitsubishi Electric Corporation (72) Inventor Nao Takagi 5-1-1, Ofuna, Kamakura-shi, Kanagawa (56) References JP-A-62-7207 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H03F 1/32 H03F 3/193

Claims (5)

(57) [Claims] An input circuit for inputting a signal, and the input circuit
Active element circuit, the active to handle more input signals
A high-frequency linear amplifier comprising an output circuit for outputting a signal processed by an element circuit to a next circuit;
To, connect an impedance conversion circuit for converting the input impedance of the active element circuit in higher than the power supply impedance impedance, the resistance on the side opposite to the side connected to the input of the active element circuit in the impedance converter circuit
The active element with respect to the power source impedance.
The input impedance change of the slave circuit is
A high-frequency linear amplifier characterized by further returning the impedance to the power supply impedance . 2. The impedance conversion circuit according to claim 2, wherein
Between the side connecting the active element circuit and the side opposite to ground
Radio frequency linear amplifier according to claim 1, characterized in that connected. 3. The method according to claim 1, wherein the resistor is an impedance conversion circuit.
The side opposite to the side connected to the active element circuit and the signal input terminal
The high circumference according to claim 1, wherein the connection is made between
Wave linear amplifier. 4. An impedance conversion circuit comprising a passive element.
4. The method according to claim 1, wherein
A high-frequency linear amplifier as described. 5. The impedance conversion circuit is a distributed constant line.
4. The method according to claim 1, wherein
A high-frequency linear amplifier according to any one of the above.