High-frequency amplifier, and transmission/reception system

1. A high-frequency amplifier including:

a reception signal amplifying part, a transmission signal amplifying part which is separate and distinct from the reception signal amplifying part, and an inductor;

said reception signal amplifying part having a reception signal input terminal, and a first transmission/reception switching control terminal;

said transmission signal amplifying part having a transmission signal input terminal, and a second transmission/reception switching control terminal; and

a common output terminal to which an output of the reception signal amplifying part and an output of the transmission signal amplifying part are connected;

wherein, switching of operations of the reception signal amplifying part and the transmission signal amplifying part is carried out such that, during a reception mode, control signals are input to the first transmission/reception switching control terminal and to the second transmission/reception switching control terminal, whereby the transmission signal amplifying part is turned off, and the reception signal amplifying part is turned on to amplify a reception signal that is inputted from the reception signal input terminal, and

during a transmission mode, control signals are input to the first transmission/reception switching control terminal and to the second transmission/reception switching control terminal, whereby the reception signal amplifying part is turned off, and the transmission signal amplifying part is turned on to amplify a transmission signal that is inputted from the transmission signal input terminal; and

said inductor is connected between a DC power supply terminal and the common output terminal as a load that is common to the reception signal amplifying part and the transmission signal amplifying part.

2. A high-frequency amplifier as defined in claim 1 further including a switch and a transmission signal output terminal, wherein

said switch is connected between the output terminal and the transmission signal output terminal;

during the reception mode, said switch is turned off, whereby the reception signal inputted from the reception signal input terminal is amplified and transmitted to the output terminal; and

during the transmission mode, said switch is turned on, whereby the transmission signal inputted form the transmission signal input terminal is amplified and transmitted to the transmission signal output terminal.

3. A high-frequency amplifier as defined in claim 1 wherein

said reception signal amplifying part has a transistor for amplifying the reception signal.

4. A high-frequency amplifier as defined in claim 3 wherein

said transistor of said reception signal amplifying part is optimized to realize noise matching.

5. A high-frequency amplifier as defined in claim 3 wherein

said transistor of said reception signal amplifying part is optimized to realize gain matching.

6. A high-frequency amplifier as defined in claim 1 wherein

said transmission signal amplifying part has a transistor for amplifying power.

7. A high-frequency amplifier as defined in claim 1 wherein said inductor comprises a spiral inductor that is mounted in an integrated circuit.

8. A high-frequency amplifier as defined in claim 1 wherein

said reception signal amplifying part, said transmission signal amplifying part, and said inductor are mounted on the same integrated circuit.

9. A high-frequency amplifier as defined in claim 1 wherein

said inductor comprises a spiral inductor that is mounted in a module.

10. A high-frequency amplifier comprising two pieces of high-frequency amplifiers defined in claim 1 , and amplifying a differential reception signal and a differential transmission signal.

11. A high-frequency amplifier as defined in claim 1 wherein

each of transistors constituting the high-frequency amplifier is any of a MOSFET, a MESFET, a JFET, a HEMT, a bipolar junction transistor, and a heterojunction transistor, or a combination of some of these transistors.

12. A high-frequency amplifier as defined in claim 1 wherein each of transistors constituting the high-frequency amplifier comprises any of silicon, silicon-germanium, and III-V compound semiconductor.

13. A high-frequency amplifier as defined in claim 1 wherein

said reception signal amplifying part has a transistor for amplifying the reception signal, and a first variable voltage supply that can vary a voltage applied between a gate of the transistor and the ground;

said transmission signal amplifying part has a transistor for amplifying power, and a second variable voltage supply that can vary a voltage applied to a gate of the transistor and the ground;

said first transmission/reception switching control terminal is connected to the first variable voltage supply;

said second transmission/reception switching control terminal is connected to the second variable voltage supply;

during the reception mode, control signals are input to the first transmission/reception switching control terminal and to the second transmission/reception switching control terminal, whereby the transmission signal amplifying part is almost turned off, and the reception signal amplifying part is turned on to amplify the reception signal inputted from the reception signal input terminal at low noise.

14. A high-frequency amplifier as defined in claim 1 including

a switch disposed between the output terminal and the reception signal input terminal, and

said switch being turned on when the reception signal has a large amplitude.

15. A high-frequency amplifier as defined in claim 1 wherein

when a capacitance that is required between the output terminal and the ground by the high-frequency amplifier is deficient due to a parasitic capacitance at the output terminal, a capacitance having a capacitance value corresponding to the deficit is connected.

16. A high-frequency amplifier as defined in claim 1 including

switches disposed between the reception signal input terminal, the transmission signal input terminal and the ground, respectively, and

the switch which is disposed at the side where the reception signal amplifying part or the transmission signal amplifying part is turned off, is turned on.

17. A high-frequency amplifier as defined in claim 1 further including a switch, an input/output terminal, and first and second capacitances, wherein

a series-connected body comprising said switch and said first capacitance is connected between a node to which the output terminal is connected, and the input/output terminal;

said input/output terminal is connected through the second capacitance to a node to which the transmission signal input terminal should be connected;

during the reception mode, said switch is turned off, and the reception signal inputted to the input/output terminal is amplified and transmitted to the output terminal; and

during the transmission mode, said switch is turned on, and the transmission signal inputted from the transmission signal input terminal is amplified and transmitted to the input/output terminal.

18. A transmission/reception system including a transmission/reception unit for transmitting and receiving a high-frequency signal,

said system including a high-frequency amplifier as defined in claim 1 , and operating in a time-division duplex communication scheme.

19. A transmission/reception system having a transmission/reception unit for transmitting and receiving a high-frequency signal,

said system including a plurality of high-frequency amplifiers as defined in claim 1 , and

being able to set whether said plural high-frequency amplifiers are simultaneously switching between the transmission mode and the reception mode, or some of them are in the transmission mode while the others are in the reception mode.

20. A high-frequency amplifier including a reception signal amplifying part, a transmission signal amplifying part which is separate and distinct from the reception signal amplifying part, an inductor, and a transistor, wherein:

said reception signal amplifying part has a reception signal input terminal, and a first transmission/reception switching control terminal;

said transmission signal amplifying part has a transmission signal input terminal, and a second transmission/reception switching control terminal;

an output of the reception signal amplifying part and an output of the transmission signal amplifying part are connected to the transistor;

switching of operations of the reception signal amplifying part and the transmission signal amplifying part is carried out such that, during a reception mode, control signals are input to the first transmission/reception switching control terminal and to the second transmission/reception switching control terminal, whereby the transmission signal amplifying part is turned off, and the reception signal amplifying part is turned on to amplify a reception signal that is inputted from the reception signal input terminal, and

during a transmission mode, control signals are input to the first transmission/reception switching control terminal and to the second transmission/reception switching control terminal, whereby the reception signal amplifying part is turned off, and the transmission signal amplifying part is turned on to amplify a transmission signal that is inputted from the transmission signal input terminal;

said inductor is connected between a DC power supply terminal and the transistor as a load that is common to the reception signal amplifying part and the transmission signal amplifying part; and

an output terminal is provided at a connection point of the inductor and the transistor.