Calibration systems and calibration method

A calibration system, comprising:

• a probe antenna that receives a radio signal at a plurality of measurement positions set on a predetermined measurement plane in a near field area of a measured antenna having a plurality of antenna elements;
• an amplitude phase measurement unit that measures amplitude and phase of the radio signal received by the probe antenna;
• and
• a back projection processing unit that calculates an amplitude distribution and a phase distribution of the radio signal on the electromagnetic radiation surface of the measured antenna based on the amplitude and the phase measured by the amplitude phase measurement unit, wherein
• the calibration system further comprises an antenna control unit that selects and excites one combination of antenna elements from among the plurality of antenna elements, and thereafter selects and excites another combination of antenna elements distinct from the one combination of the antenna elements,
• the probe antenna receives the radio signal transmitted from the respective combinations of the antenna elements,
• the back projection processing unit calculates the amplitude distribution and the phase distribution of the radio signals transmitted from the respective combinations of the antenna elements, and
• the calibration system further comprises:
• an amplitude phase extraction unit that extracts values of the amplitude and the phase corresponding to the positions of the respective combinations of the antenna elements on the electromagnetic radiation surface, from the amplitude distribution and the phase distribution calculated by the back projection processing unit;
• and
• a first phase calculation unit that calculates the phase corresponding to the respective positions of the plurality of the antenna elements on the electromagnetic radiation surface, from the values of the phase extracted by the amplitude phase extraction unit.