Patent ID: 8581791

Claim:
A communication device, comprising: a first antenna; a second antenna; a first adjustment circuit configured to adjust an impedance of the first antenna; a second adjustment circuit configured to adjust an impedance of the second antenna; a coupling reduction circuit configured to reduce an amount of coupling of the first antenna and the second antenna; a first reception power measurement unit configured to measure first reception power received from the first antenna; a second reception power measurement unit configured to measure second reception power received from the second antenna; a selection unit configured to select a circuit to be controlled by an impedance from among the first adjustment circuit, the second adjustment circuit, and the coupling reduction circuit; and a circuit control unit configured to control an impedance of the selected circuit so that a value of an evaluation function proportional to a product of the first reception power and the second reception power becomes larger; an interference power measurement unit configured to measure interference power received by the first antenna, wherein when the interference power is smaller than a threshold indicating intensity of interference power which does not improve a ratio of power of signal received by the first antenna to the interference power by increasing a gain of the first antenna, the selection unit selects the first adjustment circuit, and when the interference power is equal to or exceeds the threshold, the unit does not select the first adjustment circuit, but selects the coupling reduction circuit.