JP3018703B2 - Microwave semiconductor 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 quasi-microwave and microwave band semiconductor amplifier, and more particularly to a microwave semiconductor amplifier with less leakage of harmonics.

[0002]

2. Description of the Related Art High-output microwave semiconductor amplifiers using field-effect transistors (hereinafter abbreviated as FETs) are often used as transmitters of various communication devices. Here, an example in which an FET is used as a semiconductor element will be described. FIG.
Can be found in, for example, Proceedings of the 1990 IEICE Spring Conference, C-50, pp. It is an equivalent circuit diagram of the conventional microwave semiconductor amplifier shown by 2-472. In the figure, 1 is an FET, 2 is an input matching circuit, 3 is an output matching circuit, 4 is an input terminal, 5 is an output terminal, 6 is a bias terminal, 7 is an open-ended line for fundamental wave impedance matching, 8
Is a connection line for matching a fundamental wave impedance, and 9 is a bias circuit. This amplifier has a configuration in which an input matching circuit 2 is connected to the gate terminal of the FET 1 and an output matching circuit 3 is connected to the drain terminal of the FET 1. Each of the input matching circuit 2 and the output matching circuit 3 includes an open-end line 7 for fundamental wave impedance matching, a connection line 8 for fundamental wave impedance matching, and a DC blocking capacitor 18, and the input matching circuit 2 is connected to the input terminal 4. The output impedance matching circuit 3 is configured to match the input impedance of the FET 1 and the load impedance connected to the output terminal 5 to the output impedance of the FET 1. Further, a bias circuit 9 is provided in each of the input matching circuit 2 and the output matching circuit 3.

Next, the operation will be described. By applying a predetermined bias to the bias terminal 6, the FET 1
Is in the operating state. In such a state, the microwave input from the input terminal 4 passes through the input matching circuit 2 and
It reaches ET1, where it is amplified. The amplified microwave reaches the output terminal 5 through the output matching circuit 3 and is supplied to a mixer or the like. As described above, a predetermined bias is applied to the FET1, the input matching circuit 2 is adjusted so that the input impedance of the FET1 matches the power supply impedance, and the output matching circuit is adjusted so that the output impedance of the FET1 matches the load impedance. And input terminal 4
Is amplified and taken out to an output terminal 5.

[0004]

In microwave semiconductor amplifiers used in transmitters of various communication devices, harmonic signal components generated from the microwave semiconductor amplifiers are often suppressed in order to prevent influence on other communication devices. Required. A stub for short-circuiting a harmonic is sometimes used as a means for suppressing the harmonic.However, the stub for suppressing the harmonic affects the matching of the fundamental wave. It needs to be considered. There is also a method of configuring a stub that suppresses harmonics so as not to affect the matching of the fundamental wave. However, it is necessary to provide a stub separately from the element for matching the fundamental wave, and there is a problem that the circuit becomes large. . Further, when suppressing a plurality of harmonics, it is necessary to provide stubs by the number of harmonics to be suppressed, and several L-shaped impedance transforming circuits each composed of one transmission line and one stub are arranged in series. This means that the circuit is large
There was a problem that the configuration became complicated and the configuration became complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has a small leakage of a plurality of harmonics.
Another object is to obtain a miniaturized microwave semiconductor amplifier.

[0006]

In order to achieve the above-mentioned object, a microwave semiconductor amplifier according to the first aspect of the present invention comprises a semiconductor device such as an input matching circuit, a field effect transistor, and an output matching circuit. in the wave semiconductor amplifier, a harmonic suppression circuit comprising the open-end line having a length of one wavelength of about 4 minutes each for a plurality of harmonics in the output matching circuit are connected in parallel, to the harmonic suppression circuit common
Column-connected capacitive element, the semiconductor element, and the harmonic
The matching connection between the wave suppression circuit and the parallel connection circuit of the capacitance element
Connection line and each of the above harmonic suppression circuits, capacitive elements
In this configuration, impedance matching with respect to the fundamental wave is performed between the connector, the matching connection line, and the load .

According to a second aspect of the present invention, there is provided a microwave semiconductor amplifier including the open-ended line of the first aspect.
The connection between the parallel circuit and the capacitive element
A micro-stroke with an L-shaped or T-shaped slit
It is configured by a lip line .

[0008]

[0009]

[0010]

In the microwave semiconductor amplifier according to the first aspect of the present invention, the output matching circuit includes:
The harmonic suppression circuit, the capacitive element connected in parallel to it,
The matching connection line forms an L-shaped circuit, and the matching connection
Line length and characteristic impedance of the line, and the above-mentioned capacitive element
By setting the value of
And a large fundamental wave output can be obtained, and a plurality of harmonics are simultaneously short-circuited by an open-ended line having a length of about one quarter for each of the plurality of harmonics. And a plurality of determined harmonics can be significantly suppressed.

Further, in the microwave semiconductor amplifier according to the second aspect of the present invention configured as described above ,
In addition to the invention, a plurality of open-ended lines are connected in parallel to form
The connection between the parallel circuit and the capacitive element is L-shaped or T-shaped.
A microstrip line with a U-shaped slit
This makes it possible to create multiple lines with different line widths and lengths in a small area.
It can be realized with several open-ended lines, and can be significantly reduced in size.
Can.

[0012]

[0013]

[0014]

[Embodiment 1] Hereinafter, an embodiment of the invention according to claim 1 will be described. FIG. 1 is an equivalent circuit diagram showing Embodiment 1 of a microwave semiconductor amplifier according to the present invention. In the figure, 1 is an FET, 2 is an input matching circuit, 3 is an output matching circuit, 4 is an input terminal, 5 is an output terminal, 8 is a connection line for fundamental wave impedance matching, and 10 is a third harmonic of about 4 A first open-ended line having a length of one quarter wavelength, 11 is a second open-ended line having a length of about a quarter wavelength at the fourth harmonic. The first open-end line 10 and the second open-end line 11 constitute a harmonic suppression circuit connected in parallel, and the output matching circuit 3 comprises an L-shaped impedance transformer composed of the connection line 8 and the harmonic suppression circuit. Forming a bowl. Each constant of the harmonic suppression circuit and the connection line 8 is F
The output impedance of ET1 and the load impedance are selected so as to match. The input matching circuit 2 is F
The input impedance of ET1 and the power supply impedance are selected so as to match. The microwave semiconductor amplifier requires a bias circuit 9 for applying a predetermined bias to the semiconductor as shown in FIG. 5, and a DC blocking capacitor for preventing a bias current from leaking out of the amplifier. 18 are provided, but are omitted here for simplicity.

Next, the operation will be described. The fundamental signal input from the input terminal 4 passes through the input matching circuit 2 and
It reaches T1, where it is amplified. However, when FET1 operates as a large signal like a high-output amplifier, F1
At the drain terminal of ET1, in addition to the amplified fundamental wave signal, harmonics generated inside the FET1 also appear. The fundamental wave signal is output to the output terminal 5 through the connection line 8 and the harmonic suppression circuit. On the other hand, the above-mentioned harmonic also propagates toward the output terminal 5, but the first open-end line 10 and the second open-end line 1 forming a harmonic suppression circuit.
Since the third and fourth harmonics are short-circuited at a high frequency, the harmonics are totally reflected to the FET 1 side. Thus, the fourth and fourth harmonics are about 4
A harmonic suppression circuit formed by connecting a first open-end line 10 and a second open-end line 11 having a length of one-half wavelength in parallel is used as a matching element of an impedance transformer for a fundamental wave. As a result, it is possible to realize a microwave semiconductor amplifier which can obtain a large fundamental wave output and has less leakage of the third and fourth harmonics.

Embodiment 2 FIG. Hereinafter, the invention according to claim 1ofExamples will be described.
You. FIG. 2 shows an embodiment of the microwave semiconductor amplifier according to the present invention.
FIG. 2 is an equivalent circuit diagram showing a second example. In FIG.
The oscillation circuit 15 is a phase adjustment line.
And the parallel resonance circuit 14 are connected in series with the FET 1 and the connection line.
8 is provided. The parallel resonance circuit 14 is a secondary
Are selected so as to resonate in parallel with the harmonics of
Very high impedance for the second harmonic
It has become. Therefore, the second order generated in the FET 1
The harmonic is totally reflected by the parallel resonance circuit 14 and returns to the FET1.
You. Thus, the second harmonic generated from FET1 is
By totally reflecting and returning with the phase at the output side of the FET
Amplifiers are known to operate with high efficiency. Ma
Also, the second harmonic generated from FET1 is applied to FET1.
The phase before returning is determined by the phase adjustment line 15.
Therefore, the length of the phase adjustment line 15 is set to a value that increases the efficiency.
, The efficiency of the amplifier can be improved.
You. In this case, the impedance matching for the fundamental wave is
Considering the column resonance circuit 14 and the phase adjustment line 15,
By setting the constant between the line 8 and the harmonic suppression circuit,
It is easy. Thus, the double harmonic generated by FET1
For total reflection at a phase that increases efficiency
By adding the resonance circuit 14 and the phase adjustment line 15,
Leakage of second, third and fourth harmonics
Microwave semiconductor amplifier with high efficiency
You.

Embodiment 3 FIG. Hereinafter, an embodiment of the invention according to claim 2 will be described. In the first embodiment, the case where the harmonic suppression circuit is used as the impedance matching element for the fundamental wave has been described. The capacitance obtained by the harmonic suppression circuit is determined by the length and characteristic impedance of the first open-end line 10 and the second open-end line 11. First open end line 10 and second open end line 11
Characteristic impedance is determined by the substrate used and the line width in the case of, for example, a microstrip line. Therefore, the substrate and the line width may be restricted in realizing the characteristic impedance. In such a case, the characteristic impedance for obtaining the capacitance necessary for impedance matching with the fundamental wave cannot be realized, and the output of the fundamental wave may decrease. The invention according to claim 2 has been made to compensate for this, and will be described with reference to FIG.

FIG. 3 is an equivalent circuit diagram showing a third embodiment of the microwave semiconductor amplifier according to the present invention. The output matching circuit 3 of the microwave semiconductor amplifier is different from the output matching circuit 3 of the microwave semiconductor amplifier shown in the first embodiment in that the capacitive element 16 is connected in parallel to the harmonic suppression circuit on an equivalent circuit. . Here, an example in which a capacitor is used as the capacitive element 16 is shown. By connecting the capacitive element 16 in parallel to the harmonic suppression circuit in this way, the capacitance obtained by the harmonic suppression circuit is reduced by the capacitance of the capacitive element 1.
6 can be added.
Accordingly, the impedance matching with respect to the fundamental wave can be performed by determining the length and characteristic impedance of the connection line 8 and the above-mentioned capacitive element 16. Accordingly, it is possible to obtain a microwave semiconductor amplifier having a small fundamental wave output and a small leakage of the third and fourth harmonics.

Embodiment 4 FIG. Hereinafter, embodiments of the invention according to claims 3 and 4 will be described. FIG. 4 (a),
(B) is a diagram showing a parallel circuit formed by connecting the open-ended lines of the microwave semiconductor amplifier according to the first and second embodiments of the present invention in parallel. FIG. 4C is a diagram showing a parallel circuit formed by connecting open-ended lines of the microwave semiconductor amplifier according to the third embodiment of the present invention in parallel and a circuit including a capacitive element connected in parallel to the parallel circuit. is there. FIG. 4 (a),
(B) shows that each microstrip line has L
FIG. 1 is a view showing an example in which a first open line 10 and a second open line 11 shown in FIGS. 1 and 2 are shown in FIGS. is there. FIG. 4C shows a third embodiment in which two L-shaped slits 17 are provided in one microstrip line, and the first open-end line 10 and the second open-end line 11 of FIG. FIG. 3 is a diagram illustrating an example in which a capacitive element 16 is configured. In this case, a case where an open-ended line is used as the capacitive element 16 is shown. By arranging the first open-end line 10 and the second open-end line 11 and the capacitive element 16 which constitute a parallel circuit in this manner, each line 10, 1
1 and the capacitive element 16 are coupled to each other. In consideration of this coupling, the length and width of the slit 17 and each line 10, 1
1 and the length of the capacitive element 16 and the line width, the characteristic impedance of each of the lines 10 and 11 and the capacitive element 16 is determined.
Dance and electric length can be set. With the above configuration, the size of the parallel circuit can be significantly reduced. Therefore, by using the parallel circuit configured as described above as an impedance matching element for a fundamental wave, it is possible to obtain a small-sized microwave semiconductor amplifier with less harmonic leakage.

In the above-described embodiment, the first open-ended line 10 and the second open-ended line 10 each having a length of about a quarter wavelength for the third and fourth harmonics are used as the harmonic suppression circuit. The above description has been made on the case where the open-ended lines 11 are connected in parallel. However, the present invention is not limited to this, and the open-ended lines each having a length of about one-quarter wavelength are also used for other harmonics. The same effect can be obtained even if the connection is made in parallel.

In addition, an open-ended line having a length of about a quarter wavelength for each of three or more harmonics may be connected in parallel as a harmonic suppression circuit.
More harmonics can be suppressed at the same time.

[0022]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, a plurality of harmonics
Open ends each having a length of about one-quarter wavelength
A harmonic suppression circuit composed of parallel discharge lines and a harmonic suppression circuit.
Impedance adjustment with the capacitive element connected in parallel to the voltage circuit.
By using as a combining element, a large fundamental wave output can be obtained, and a microwave semiconductor amplifier with less leakage of harmonics can be obtained.

According to the second aspect of the present invention, the first aspect of the present invention is provided.
In addition to the effect of
Thus, a small-sized microwave semiconductor amplifier can be obtained.

[0025]

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a microwave semiconductor amplifier according to a first embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram of a microwave semiconductor amplifier according to a second embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram of a microwave semiconductor amplifier according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a parallel circuit formed by connecting a plurality of open-ended lines of a microwave semiconductor amplifier according to a fourth embodiment of the present invention in parallel;

FIG. 5 is an equivalent circuit diagram of a conventional microwave semiconductor amplifier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Field-effect transistor (FET) 2 Input matching circuit 3 Output matching circuit 4 Input terminal 5 Output terminal 6 Bias terminal 7 Matching free end line 8 Matching connecting line 9 Bias circuit 10 First free end line 11 Second free end Open line 12 Inductor 13 Inductor 14 Parallel resonance circuit 15 Phase adjustment line 16 Capacitive element 17 Slit

Continuation of the front page (72) Inventor Naoki Takagi 5-1-1, Ofuna, Kamakura-shi Mitsubishi Electric Corporation Electronic Systems Laboratory (56) References JP-A-62-161411 (JP, A) JP-A-1- 284001 (JP, A) Fully open sho 59-101502 (JP, U) Fully open sho 60-114419 (JP, U) Frederick H. Larp, "Operational Classification of High-Efficiency Amplifier Circuits" (Nikkei Electronics, 1976) FIG. 6 (58) of the August 23rd issue, pp. 121-146) Investigated field (Int. Cl. ⁷ , DB name) H03F 3/60 H01P 5/02 603

Claims (2)

(57) [Claims] 1. A microwave semiconductor amplifier comprising an input matching circuit, a semiconductor element such as a field effect transistor, and an output matching circuit, wherein the output matching circuit has a plurality of harmonics each having a length of about 波長 wavelength. Harmonic suppression circuit formed by connecting open-ended lines having different lengths in parallel, a capacitive element connected in parallel to the harmonic suppression circuit, the semiconductor element, and a parallel connection circuit of the harmonic suppression circuit and the capacitance element A microwave semiconductor amplifier, comprising: a matching connection line provided between the harmonic connection circuits, a capacitive element, a matching connection line, and a load for impedance matching with a fundamental wave. 2. A microstrip line having an L-shaped or T-shaped slit, wherein both a parallel circuit formed by connecting open-ended lines in parallel and a capacitive element are connected. Microwave semiconductor amplifier.