Radio communication transceiver

A radio communication transceiver comprising:

• a first frequency multiplier configured to multiply a frequency of a local oscillator (LO) signal;
• a mixer configured to mix the LO signal and an intermediate frequency (IF) signal output from the first frequency multiplier to generate a radio frequency (RF) signal;
• a cancel signal generator configured to generate a cancel signal to cancel LO leakage generated in the mixer;
• an antenna configured to transmit an RF signal;
• and
• a multiplexer configured to output a signal obtained by adding the output signal of the mixer and the cancel signal to the antenna, wherein
• the cancel signal generator generates the cancel signal having a same absolute value of strength and an opposite phase at a same frequency with respect to the LO leakage generated in the mixer and input to the multiplexer.

A radio communication transceiver comprising:

• a first frequency multiplier configured to multiply a frequency of a local oscillator (LO) signal;
• a first variable attenuator configured to attenuate an output signal of the first frequency multiplier;
• a first mixer configured to mix an LO signal output from the first variable attenuator and an intermediate frequency (IF) signal for a first channel to generate a radio frequency (RF) signal for the first channel;
• a first filter configured to filter an output signal of the first mixer to pass the RF signal for the first channel;
• a variable phase shifter configured to shift a phase of a same signal as the LO signal input to the first frequency multiplier and output the signal;
• a second frequency multiplier configured to multiply a frequency of an output signal of the variable phase shifter by a same multiple as the first frequency multiplier;
• a second variable attenuator configured to attenuate an output signal of the second frequency multiplier;
• a second mixer configured to mix an LO signal output from the second variable attenuator and an IF signal for a second channel to generate an RF signal for the second channel;
• a second filter configured to filter an output signal of the second mixer to pass the RF signal for the second channel;
• an antenna configured to transmit an RF signal;
• and
• a multiplexer configured to output, to the antenna, a signal obtained by adding an output signal of the first filter and an output signal of the second filter, wherein
• the variable phase shifter shifts the phase of the same signal as the LO signal input to the first frequency multiplier and outputs the signal so that LO leakage input from the first filter to the multiplexer and LO leakage input from the second filter to the multiplexer have opposite phases, and
• the first and second variable attenuators attenuate the output signals of the first and second frequency multipliers so that an absolute value of strength of the LO leakage input from the first filter to the multiplexer is identical to an absolute value of the strength of the LO leakage input from the second filter to the multiplexer.

A radio communication transceiver comprising:

• a first frequency multiplier configured to multiply a frequency of a local oscillator (LO) signal;
• a first variable attenuator configured to attenuate an output signal of the first frequency multiplier;
• a first mixer configured to mix an LO signal output from the first variable attenuator and an intermediate frequency (IF) signal for a first channel to generate a radio frequency (RF) signal for the first channel;
• a first antenna configured to transmit an RF signal for a first channel;
• a first filter configured to filter an output signal of the first mixer and output an RF signal for a first channel to the first antenna;
• a variable phase shifter configured to shift a phase of a same signal as the LO signal input to the first frequency multiplier and output the signal;
• a second frequency multiplier configured to multiply a frequency of an output signal of the variable phase shifter by a same multiple as the first frequency multiplier;
• a second variable attenuator configured to attenuate an output signal of the second frequency multiplier;
• a second mixer configured to mix an LO signal output from the second variable attenuator and an IF signal for a second channel to generate an RF signal for the second channel;
• a second antenna configured to transmit the RF signal for the second channel;
• and
• a second filter configured to filter an output signal of the second mixer and output the RF signal for the second channel to the second antenna, wherein
• the variable phase shifter shifts the phase of the same signal as the LO signal input to the first frequency multiplier and outputs the signal so that LO leakage transmitted from the first antenna and received by a third antenna on a reception side and LO leakage transmitted from the second antenna and received by the third antenna have opposite phases, and
• the first and second variable attenuators attenuate output signals of the first and second frequency multipliers so that an absolute value of strength of the LO leakage transmitted from the first antenna and received by the third antenna is same as an absolute value of strength of the LO leakage transmitted from the second antenna and received by the third antenna.