Radio communication apparatus and phase adjustment method

A phase adjustment method for use in a radio communication apparatus having a first antenna, a second antenna, a third antenna, and a processor, the phase adjustment method comprising:

• varying, by the processor, a phase difference between a first signal transmitted from the first antenna and a second signal transmitted from the second antenna;
• measuring, by the processor, a received power pattern of a synthesized signal of the first signal and the second signal, the synthesized signal being received by the third antenna;
• and
• adjusting, by the processor, a phase shift of a signal that is transmitted from the first antenna or the second antenna, based on a difference between the measured received power pattern and a received power pattern obtained by calculation,
• wherein:
• the processor calculates the received power pattern based on an attenuation coefficient dependent on a distance between the first antenna and the third antenna, and dependent on a distance between the second antenna and the third antenna,
• the processor calculates a first phase difference that maximizes the calculated received power pattern and a second phase difference that minimizes the calculated received power pattern,
• the processor measures a third phase difference that maximizes the measured received power pattern and a fourth phase difference that minimizes the measured received power pattern,
• the processor detects a first phase shift by comparing the first phase difference with the third phase difference and a second phase shift by comparing the second phase difference with the fourth phase difference, and
• the processor adjusts the phase shift of the signal that is transmitted from the first antenna or the second antenna by a value that is determined based on the first phase shift and the second phase shift.