A communication device using wireless power, the communication device comprising: a controller configured to control mutual resonance between a source resonator, comprising a first capacitor, C 1, and a first inductor, L 1, which are connected to a power input by means of a first switch,, and a target resonator, comprising a second capacitor, C 2, and a second inductor, L 2, which are connected to a power output by means of a second switch; a demodulator configured to demodulate at the target resonator information transmitted from the source resonator based on an amount of energy received from the source resonator; and a modulator configured to modulate at the source resonator information based on the mutual resonance, wherein the controller is configured to: turn the first switch to an ON state to provide power from the power input to the source resonator; turn the first switch to an OFF state when power stored in the source resonator reaches a first predetermined value; turn the second switch to an OFF state so that the target resonator receives energy, transmitted from the source resonator, through mutual resonance for one or more symbol duration periods; turn the second switch to an ON state when power charged in the target resonator reaches a second predetermined value, and determine whether at least one further target resonator, other than the target resonator, mutually resonates with the source resonator. a controller configured to control mutual resonance between a source resonator, comprising a first capacitor, C 1, and a first inductor, L 1, which are connected to a power input by means of a first switch,, and a target resonator, comprising a second capacitor, C 2, and a second inductor, L 2, which are connected to a power output by means of a second switch; a demodulator configured to demodulate at the target resonator information transmitted from the source resonator based on an amount of energy received from the source resonator; and a modulator configured to modulate at the source resonator information based on the mutual resonance, wherein the controller is configured to: turn the first switch to an ON state to provide power from the power input to the source resonator; turn the first switch to an OFF state when power stored in the source resonator reaches a first predetermined value; turn the second switch to an OFF state so that the target resonator receives energy, transmitted from the source resonator, through mutual resonance for one or more symbol duration periods; turn the second switch to an ON state when power charged in the target resonator reaches a second predetermined value, and determine whether at least one further target resonator, other than the target resonator, mutually resonates with the source resonator. turn the first switch to an ON state to provide power from the power input to the source resonator; turn the first switch to an OFF state when power stored in the source resonator reaches a first predetermined value; turn the second switch to an OFF state so that the target resonator receives energy, transmitted from the source resonator, through mutual resonance for one or more symbol duration periods; turn the second switch to an ON state when power charged in the target resonator reaches a second predetermined value, and determine whether at least one further target resonator, other than the target resonator, mutually resonates with the source resonator.