JP2001274631A - Balanced fet mixer and communication unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a balanced FET mixer that less outputs spurious radiation waves even at any operating ambient temperature. SOLUTION: The balanced FET mixer provided with 1st and 2nd frequency mixing FET elements placed in parallel, a signal wave distributor that distributes a signal wave into two input terminals of the 1st and 2nd FETs, and an output wave synthesizer that composites output waves from the 1st and 2nd FET elements, is provided with a balanced temperature compensation control circuit that respectively sets the gate biases of the 1st and 2nd FETs accordingly to a temperature fluctuation of the environment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to suppression of spurious in a balanced FET mixer used in a microwave band.

[0002]

2. Description of the Related Art FIG. 10 shows a conventional configuration example of a balanced FET mixer generally used for suppressing spurious. In the figure, 1 is an input terminal, 2 is an output terminal, 3 is FE
T, 4 are gate terminals, 5 is a drain terminal, 6 is an input wave distribution circuit, 7 is an output wave synthesis circuit, 10 is a gate bias terminal, and 21 is a resistance voltage dividing circuit.

Next, the operation will be described. Here, when a 180-degree distributor for distributing the phases of the signal wave and the local oscillation wave in opposite phases to the input wave distribution circuit 6 and an in-phase combiner for combining the output signal in the same phase with the output wave combining circuit 7, FIG. In the conventional balanced FET mixer shown in FIG.
From the input signal wave and the local oscillation wave, the respective signals are distributed in opposite phases by the input wave distribution circuit 6 and input to the gate terminals 4a and 4b of the FETs 3a and 3b. In each FET, the frequency mixing of the signal wave and the local oscillation wave is performed by utilizing the nonlinearity of the semiconductor element, and the frequency mixing wave is output from the drain terminals 5a and 5b of each FET and is included in the frequency mixing wave. Are combined in the same phase by the output wave combiner 7 and taken out from the output terminal 2.

[0004] Here, as shown in FIG.
The phase difference between the desired signals respectively output from 3b is 0 degree, and the multiplied wave of the local oscillation wave is 180 degrees.

[0005] This balanced FET mixer is composed of each FET 3a,
Since the output of the output 3b is combined with the output wave combiner 7 in the same phase, the signals output from the FETs 3a and 3b having a phase difference of 0 degree like the desired signal wave are combined. , And a signal having a phase difference of 180 degrees, such as a multiple wave of a local oscillation wave, is suppressed.

Further, in the conventional example, the signal wave distributor is distributed as 180 degrees and the output wave combiner is described as the in-phase combiner. However, the phases of the signal wave to be taken out and the unnecessary wave to be suppressed are combined and canceled, respectively. Then, the signal wave distributor and the output wave combiner may have any distribution and combined phase.

[0007]

In a conventional balanced FET mixer, two FETs used side by side do not have exactly the same characteristics, so that changes in electrical characteristics due to changes in ambient environmental temperature are different from each other. In addition, the amplitude and the phase of the unnecessary waves output from the two FETs are slightly different from each other.

FIG. 12 shows an experimental example of a change in the output level of the unnecessary wave at the output terminal 5 with respect to a change in the temperature of the environment of the conventional balanced mixer. Each FET
Each of the FETs 3a, 3b is kept at room temperature so that the output of the
However, the electrical characteristics of each FET change as the environmental temperature changes.
It is not suppressed enough because the phase is slightly different,
The output level of the unnecessary wave is increasing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to obtain a balanced FET mixer having a small output of unnecessary waves at any used environmental temperature.

[0010]

Means for Solving the Problems The balanced FE of the first invention is provided.
The T mixer is provided with an equilibrium temperature compensation control circuit for setting each FET gate bias in accordance with the temperature fluctuation of the environment.

A balanced FET mixer according to a second aspect of the present invention is provided with a balanced temperature compensation control circuit for setting each FET drain bias in response to environmental temperature fluctuations.

A balanced FET mixer according to a third aspect of the present invention comprises a signal wave distributor for connecting between each FET or each F.
A phase shifter is provided between the ET and the output wave synthesizer, or both, and an equilibrium temperature compensation control circuit for setting the phase of the phase shifter in accordance with the temperature fluctuation of the environment is provided.

According to a fourth aspect of the present invention, there is provided a balanced FET mixer comprising:
An amplitude variable device is provided between the ET and the output wave synthesizer, or both, and a balanced temperature compensation control circuit for setting the amplitude of the amplitude variable device according to the temperature fluctuation of the environment is provided.

According to a fifth aspect of the present invention, there is provided a balanced FET mixer comprising:
In the balanced temperature compensation control circuit for balanced FET mixers according to the fourth to fourth aspects of the present invention, a balanced temperature compensation control is performed using a thermistor or a posistor.

According to a sixth aspect of the present invention, there is provided a balanced FET mixer comprising:
In the balanced temperature compensation control circuit of the balanced FET mixer according to the fourth invention, the RO storing the temperature control data is provided.
M is provided, and temperature compensation control is performed based on the data.

According to a seventh aspect of the present invention, there is provided a balanced FET mixer comprising:
The present invention is configured to control equilibrium temperature by combining several methods according to the sixth to sixth aspects of the present invention.

According to an eighth aspect of the present invention, there is provided a communication apparatus using the balanced FET mixer according to any one of the first to seventh aspects.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows the configuration of a balanced FET mixer according to Embodiment 1 of the present invention.
In FIG. 1, 8 is a balanced temperature compensation control circuit, and 9 is a control signal input terminal.

Next, the operation will be described. Here, a 180-degree distributor that distributes the phases of the signal wave and the local oscillation wave in opposite phases to the input wave distribution circuit 6 and an in-phase combiner that combines the signals in the same phase with the output wave combining circuit 7 are shown in FIG. 1
In the conventional balanced FET mixer shown in FIG. 0, the signal wave and the local oscillation wave input from the input terminal 1 are distributed in the input wave distribution circuit 6 in opposite phases, and the gates of the FETs 3a and 3b are Input to terminals 4a and 4b. In each FET, the frequency mixing of the signal wave and the local oscillation wave is performed using the nonlinearity of the semiconductor element, and the frequency mixed wave is output from the drain terminals 5a and 5b of each FET,
A desired output wave included in the frequency-mixed wave is converted into an output wave combiner 7
Are combined in the same phase and taken out from the output terminal 2.

FIG. 2 shows the gate voltage Vg2 of the second FET 3b.
7 is an experimental example showing a change in the output level of the unnecessary wave at the output terminal 5 with respect to the gate voltage Vg1 of the first FET 3a when the constant is fixed. It can be seen that there is Vg1 at which the output level of the unnecessary wave is minimized. Further, as shown in FIG. 3, Vg1 at which the unnecessary wave output level is minimized changes according to the environmental temperature.

Here, for example, the equilibrium temperature compensation control circuit 8 performs control such that Vg1 has the characteristic shown in FIG. 3 with respect to a change in environmental temperature. Thus, the unnecessary wave output level can be minimized.

In the above example, Vg1 is controlled.
Only g2 or both Vg1 and Vg2 may be controlled.

Embodiment 2 FIG. FIG. 4 shows a configuration of a balanced FET mixer according to a second embodiment of the present invention. In FIG. 4, reference numeral 11 denotes a drain bias terminal. FIG.
The same or corresponding parts as those of the conventional example shown in FIG. 1 and the first embodiment shown in FIG.

The signal input from the input terminal 1 is input to the gate terminal 4 of each FET 3 via the input wave distribution circuit 6.
As in the first embodiment, the frequency mixed waves mixed by the respective FETs 3 are output from the drain terminal 5 of each FET, and the desired output waves included in the frequency mixed waves are synthesized by the output wave synthesizer 7, The unnecessary wave is suppressed by the output wave combiner 7 and output from the output terminal 2.

Here, the balance temperature compensation control circuit 8
Drain voltage Vd1 of the FET 3a or the second FET
By controlling the drain voltage Vd2 of 3b or both so as to minimize the unnecessary wave output level at each temperature as in the first embodiment, it is possible to realize a mixer having a small unnecessary wave output at any environmental temperature.

Embodiment 3 FIG. FIG. 5 shows the configuration of a balanced FET mixer according to Embodiment 3 of the present invention. In FIG. 3, reference numeral 12 denotes a phase shifter, and 13 denotes a phase shifter control signal input terminal. Further, the same or corresponding parts as those in the conventional example shown in FIG. 10 and the first embodiment shown in FIG.

The signal input from the input terminal 1 is input to the gate terminal 4 of the FET 3 via the input wave distribution circuit 6. As in the first embodiment, the frequency-mixed waves mixed by the respective FETs 3 are output from the drain terminals 5 of the respective FETs, and the respective signals are output from the respective phase shifters 12a and 12b.
The phase is set according to the equation (1) and input to the output wave synthesizer 7. A desired output wave included in the frequency-mixed wave is synthesized by the output wave synthesizer 7, and unnecessary waves are suppressed by the output wave synthesizer 7 and output from the output terminal 2.

Generally, the amount of unwanted wave suppression of a balanced mixer is
It increases as the phase and amplitude imbalance of each signal to be balanced increases.

Therefore, the balance temperature compensation control circuit 8
The phase shifter 12a or the second phase shifter 12b or both of the phase shifters 12a and 12b are controlled in phase so that the spurious wave output level is minimized at each temperature, and the combined phase is optimally balanced. By doing so, it is possible to realize a mixer having a small unnecessary wave output at any environmental temperature.

Embodiment 4 FIG. 6 shows a configuration of a balanced FET mixer according to a fourth embodiment of the present invention. In FIG. 6, reference numeral 14 denotes a variable attenuator, and 15 denotes a variable attenuator control signal input terminal. Further, the same or corresponding parts as those in the conventional example shown in FIG. 10 and the first embodiment shown in FIG.

The signal input from the input terminal 1 is input to the gate terminal 4 of the FET 3 via the input wave distribution circuit 6. As in the first embodiment, the frequency-mixed waves mixed by the respective FETs 3 are output from the drain terminals 5 of the respective FETs, and the respective signals are output from the respective variable attenuators 14a, 1a.
The amplitude is set by 4b and input to the output wave synthesizer 7.
The desired output wave included in the frequency mixed wave is output wave synthesizer 7
The unnecessary wave is suppressed by the output wave combiner 7 and output from the output terminal 2.

Here, the equilibrium temperature compensation control circuit 8
The amplitude of the variable attenuator 14a or the second variable attenuator 14b or both variable attenuators 14a and 14b is controlled so that the unnecessary wave output level is minimized at each temperature, and the combined amplitude is adjusted to the optimum balance condition. By doing so, it is possible to realize a mixer having a small unnecessary wave output at any environmental temperature.

Similar effects can be obtained by controlling the amplitude using a variable gain amplifier instead of a variable attenuator as shown in FIG. In FIG. 7, 16 is a variable gain amplifier,
Reference numeral 17 denotes a variable gain amplifier control signal input terminal.

Embodiment 5 FIG. 8 shows a configuration of a balanced FET mixer according to the fifth embodiment of the present invention, and shows a specific configuration of the balanced temperature compensation control circuit used in the first embodiment. In FIG. 8, reference numeral 18 denotes a thermistor. Further, the same or corresponding parts as those in the conventional example shown in FIG. 10 and the first embodiment shown in FIG.

In the circuit for setting the gate voltage Vg1 of the first FET 3a, a structure is used in which a resistor voltage dividing circuit using a fixed resistor is used and the thermistor 18 whose resistance value changes according to the environmental temperature is used. 1 F
Each constant is set so that the gate voltage Vg1 of the ET 3a has the characteristic shown in FIG. Gate voltage of first FET 3a
Vg1 change characteristics include thermistor resistance and temperature coefficient,
A desired set voltage with respect to the environmental temperature can be produced by the resistance value used in combination or the configuration of the voltage dividing circuit. Further, the gate bias of the second FET 3b is set by a resistance voltage dividing circuit using a fixed resistance.

By using the equilibrium temperature compensation control circuit using a thermistor in this way, it is possible to realize a mixer with less unnecessary wave output at any environmental temperature without requiring external control.

Here, the gate voltage of the first FET 3a is
The configuration in which Vg1 is varied and the gate voltage Vg2 of the second FET 3b is fixed has been described. However, a method in which Vg1 is varied and Vg2 is fixed or both Vg1 and Vg2 are varied and controlled is also effective. .

Although the thermistor is used in the above example,
Depending on the temperature compensation characteristic, a posistor or both may be used.

Further, in this embodiment, an example of the balanced temperature compensation control circuit used in the first embodiment has been described. However, the same circuit is used for the balanced temperature compensation control circuits used in the second to fourth embodiments. Has the same effect.

Embodiment 6 FIG. FIG. 9 shows a configuration of a balanced FET mixer according to Embodiment 6 of the present invention, and relates to a balanced temperature correction control circuit used in Embodiment 1 described above. In FIG. 9, 19 is a temperature sensor and 20 is RO
M and 21 are D / A converters. Further, the same or corresponding parts as those in the conventional example shown in FIG. 10 and the first embodiment shown in FIG.

The value of the gate voltage Vg1 of the first FET 3a is set to RO so that the unnecessary wave output level at the output terminal 2 becomes the minimum at each temperature, as shown in FIG.
It is stored in M20. Based on the temperature information detected by the temperature sensor 19, the optimum Vg1 set value at each temperature is set to RO
The digital data output from M20 is converted into an analog voltage by the D / A converter 21 to set the gate voltage of the first FET 3a. Further, the gate bias of the second FET 3b is set by a resistance voltage dividing circuit using a fixed resistance.

As described above, by performing control so that an optimum gate voltage can be set at each temperature, a mixer having a small unnecessary wave output at any environmental temperature can be realized without requiring external control.

Here, the gate voltage of the first FET 3a is
Although the configuration in which Vg1 is varied and the gate voltage Vg2 of the second FET 3b is fixed has been described, controlling Vg1 and fixing Vg2 or varying both Vg1 and Vg2 has the same effect. .

In this embodiment, an example of the equilibrium temperature compensation control circuit 8 used in the first embodiment has been described. However, a similar circuit is used for the equilibrium temperature compensation control circuits used in the second to fourth embodiments. Has the same effect.

Embodiment 7 This embodiment is a balanced FET mixer having a configuration in which the methods described in the first to sixth embodiments are appropriately combined. By combining each method, each F synthesized at any environmental temperature
Since the signal from the ET can be set to the optimum amplitude and phase conditions for the balance, a mixer with less unnecessary wave output at any environmental temperature can be realized.

In the first to seventh embodiments, the signal wave and the local oscillation wave are inputted from the input terminal 1 and the frequency mixed wave is taken out from the output terminal 2. However, the signal wave is inputted from the input terminal 1. FET configured to receive a local oscillation wave from output terminal 2 and extract a frequency mixed wave from output terminal 2
Mixers can be used.

Embodiment 8 FIG. This embodiment is a communication device using the balanced FET mixer shown in the first to seventh embodiments. For example, taking a repeater used in a satellite communication system as an example, a received wave input to the repeater is amplified by a low-noise amplifier and input to the balanced FET mixer described in any of the first to seventh embodiments. Frequency conversion is performed by this balanced FET mixer, and unnecessary waves are suppressed at any environmental temperature, and the signal is output via a power amplifier at a subsequent stage. For this reason. There is an effect that a signal with less unnecessary waves can be sent out from the repeater.

[0048]

According to the first to fourth aspects of the invention, there is an effect that an FET mixer with a small unnecessary wave output can be obtained at any environmental temperature.

According to the fifth to seventh aspects, there is an effect that a mixer having a small unnecessary wave output can be obtained at any environmental temperature without requiring external control.

According to the eighth aspect, by applying the balanced FET mixer according to any one of the first to seventh aspects, it is possible to obtain a communication device having a small unnecessary wave output at any environmental temperature. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an FET mixer according to Embodiment 1 of the present invention.

FIG. 2 is an example of a spurious level with respect to a bias voltage of a balanced FET mixer for explaining the first embodiment;

FIG. 3 is an example of an optimum bias voltage with respect to an ambient temperature of a balanced FET mixer according to the first embodiment.

FIG. 4 is a configuration diagram of an FET mixer according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of an FET mixer according to a third embodiment of the present invention.

FIG. 6 is a configuration diagram of an FET mixer according to a fourth embodiment of the present invention.

FIG. 7 is another configuration diagram of the FET mixer according to the fourth embodiment of the present invention.

FIG. 8 is a configuration diagram of an FET mixer according to a fifth embodiment of the present invention.

FIG. 9 is a configuration diagram of an FET mixer according to a sixth embodiment of the present invention.

FIG. 10 is a configuration diagram of an FET mixer having a conventional configuration.

FIG. 11 is an explanatory diagram showing an example of the operation of an FET mixer having a conventional configuration.

FIG. 12 is an example of a spurious level characteristic with respect to an ambient temperature of a conventional balanced FET mixer.

[Explanation of symbols]

1 input terminal, 2 output terminal, 3 FET, 4 gate terminal, 5 drain terminal, 6 signal wave distributor, 7 output wave synthesizer, 8 balanced temperature compensation control circuit, 9 control signal input terminal,
10 gate bias terminal, 11 drain bias terminal, 12 phase shifter, 13 phase shifter control signal input terminal, 14
Variable attenuator, 15 Variable attenuator control signal input terminal, 16
Variable gain amplifier, 17 Variable gain amplifier, control signal input terminal, 18 thermistor, 19 temperature sensor, 20 RO
M, 21 D / A converter.

Claims (8)

[Claims] A first and a second frequency mixing FET element provided in parallel with the first and second FETs;
In the balanced type FET mixer including the signal wave distributor for dividing the input wave into two input terminals and the output wave combiner for combining the output waves of the first and second FET elements, the first and second F
A balanced FET mixer comprising a balanced temperature compensation control circuit for setting a gate bias of the ET in response to environmental temperature fluctuations. 2. The first and second frequency mixing FET elements provided in parallel with each other and the first and second FETs for transmitting a signal wave to the first and second frequency mixing FET elements.
In the balanced type FET mixer including the signal wave distributor for dividing the input wave into two input terminals and the output wave combiner for combining the output waves of the first and second FET elements, the first and second F
A balanced FET mixer comprising a balanced temperature compensation control circuit for setting a drain bias of an ET in response to environmental temperature fluctuations. 3. The first and second frequency mixing FET elements provided in parallel, and the first and second FETs for transmitting a signal wave to the first and second frequency mixing FET elements.
A balanced FET mixer comprising: a signal wave distributor for dividing the signal wave into two input terminals; and an output wave combiner for combining the output waves of the first and second FET elements. , A phase shifter provided between the first and second FETs or between the first and second FETs and the output wave combiner, or both, and a phase shifter corresponding to environmental temperature fluctuations. And an equilibrium temperature compensation control circuit for setting the temperature of each of the FETs. 4. A first and second frequency mixing FET element provided in parallel, and a first and second FETs for transmitting a signal wave to the first and second frequency mixing FET elements.
A balanced FET mixer comprising: a signal wave distributor for dividing the input wave into two input terminals; and an output wave combiner for combining the output waves of the first and second FET elements. 1, between the second FET or the first and second FEs
An amplitude variable device provided between T and the output wave synthesizer or both of them, and a balanced temperature compensation control circuit for setting the amplitude of the amplitude variable device in accordance with the temperature fluctuation of the environment are provided. Balanced FET mixer. 5. The balanced FET mixer according to claim 1, wherein said balanced temperature compensation control circuit performs temperature compensation control using a thermistor, a posistor, or a combination thereof. 6. The equilibrium temperature compensation control circuit has a temperature sensor and a ROM storing data for temperature control, and controls temperature control corresponding to temperature information of the temperature sensor output from the ROM. The balanced FET mixer according to any one of claims 1 to 4, wherein temperature compensation control is performed by use data. 7. A first and a second frequency mixing FET element provided in parallel, and a signal wave from the first and second FETs.
7. A balanced FET mixer comprising: a signal wave distributor for dividing the input wave into two input terminals; and an output wave combiner for combining the output waves of the first and second FET elements. A balanced type FET mixer characterized in that a balance of temperature control is performed by combining some of the described methods. 8. The balanced type F according to claim 1,
A communication device comprising an ET mixer.