Radio device

1. A radio device comprising:

a differential antenna that has a pair of differential power supply terminals;

a transmitter that transmits a first signal via the differential antenna;

a receiver that has a pair of differential input terminals and receives a second signal via the differential antenna;

a first switch unit that switches a signal conduction state and a signal block state between one of the differential input terminals and one of the differential power supply terminals;

a second switch unit that switches a signal conduction state and a signal block state between the other of the differential input terminals and the other of the differential power supply terminals;

a first control unit that controls the first switch unit and the second switch unit such that the signal block state is caused when the transmitter transmits the first signal; and

a second control unit that switches either the first switch unit or the second switch unit from the signal conduction state to the signal block state when the second signal is being received.

2. The radio device according to claim 1 , wherein the first switch unit and the second switch unit respectively have:

a first switch that is connected at one end to the differential input terminal and is connected at the other end to the differential power supply terminal; and

a second switch that is connected at one end to a connection point between the differential input terminal and one end of the first switch and is grounded at the other end,

wherein the first control unit powers off the first switch and powers on the second switch when the transmitter transmits the first signal, and powers on the first switch and powers off the second switch when the receiver receives the second signal, and

the second control unit inverts ON/OFF of either the first switch or the second switch in the first switch unit and the second switch unit based on the second signal received by the receiver.

3. The radio device according to claim 2 , further comprising a signal processing unit that measures a spectrum of the second signal received by the receiver,

wherein the second control unit determines whether to power on or off the first switch and the second switch in the first switch unit and the second switch unit based on the measurement result of the signal processing unit.

4. The radio device according to claim 1 , comprising a plurality of transmission/reception systems including the differential antenna, the first switch unit and the second switch unit,

wherein when the receiver receives the second signal, the first control unit puts the first switch unit and the second switch unit in the same transmission/reception system as the differential antenna used for receiving the second signal in the signal conduction state, and puts the first switch unit and the second switch unit in the same transmission/reception system as the differential antenna not used for receiving the second signal in the signal block state.

5. The radio device according to claim 1 , further comprising:

a third switch unit that switches a signal conduction/block state between one of a pair of differential output terminals provided in the transmitter and one of the differential power supply terminals; and

a fourth switch unit that switches a signal conduction/block state between the other of the differential output terminals and the other of the differential power supply terminals,

wherein the first control unit controls the third switch unit and the fourth switch unit such that the signal conduction state is caused when the first signal is to be transmitted and the signal block state is caused when the second signal is to be received.