| 主权项 |
1. An impedance matching apparatus configured to perform impedance matching between input impedance of a transmitting antenna and output impedance of a power supply configured to supply electric power to the transmitting antenna, said impedance matching apparatus comprising:
a matching circuit electrically disposed between the power supply and the transmitting antenna and having a plurality of variable reactance elements; an incident signal/reflected signal extracting circuit electrically disposed between the power supply and said matching circuit, and configured to extract an incident signal, which is electric power transmitted from the power supply to the transmitting antenna, and a reflected signal, which is electric power transmitted from the transmitting antenna to the power supply; an estimating device configured to estimate the input impedance on the basis of the extracted incident signal and the extracted reflected signal; and a setting device configured to perform (i) a first step of calculating a theoretical value associated with one part of the plurality of variable reactance elements such that the output impedance theoretically matches the input impedance on the basis of the estimated input impedance, and of setting a value associated with one part of the plurality of variable reactance elements such that the value becomes the calculated theoretical value, and (ii) a second step of changing a value associated with at least one of the plurality of variable reactance elements in a condition that an absolute value of the reflected signal extracted by said incident signal/reflected signal extracting circuit after the first step is greater than a first threshold value, of comparing the absolute value of the reflected signal extracted by said incident signal/reflected signal extracting circuit after changing the value associated with at least one of the plurality of variable reactance elements, and of setting a current value associated with one part of the plurality of variable reactance elements as an official value if the compared absolute value is less than or equal to the first threshold value. |
