A communication device that includes an antenna including a first electrode and a second electrode, at least one of the first electrode or the second electrode including a plurality of segmented electrodes. The communication device further includes a communication circuit, coupled to the antenna, that performs a transmission operation and a reception operation of transmission data between a device and the communication circuit based on a communication protocol that includes a plurality of communication stages. The communication device further includes a switch that switches whether or not each of the plurality of segmented electrodes is to be coupled to the communication circuit and a controller that changes an effective electrode area of at least one of the first electrode or the second electrode by the switch, based on at least one of the operations of the communication circuit, a type of the transmission data, or the communication stages.