Communication system

A communication device comprising:

• an electric field generation electrode for generating an electric field;
• and
• modulation means for performing modulation according to information to be sent so that an electrification target is electrified by a quasi-electrostatic field out of the electric field generated from the electric field generation electrode, and outputting a modulated signal resulted from the modulation, to the electric field generation electrode,
• wherein the electrification target is a human body, and
• wherein the modulation means performs the modulation according to information to be sent so that a relation of r=λ/2π is satisfied where a longest distance between the electric field generation electrode and a detection electrode for detecting the quasi-electrostatic field is taken to r and a wavelength of the modulated signal to be output to the electric field generation electrode is taken to λ.

A communication device comprising:

• detection means for detecting an electrification condition of an electrification target electrified by a quasi-electrostatic field out of an electric field based on a modulated signal obtained through modulation according to information to be sent;
• and
• demodulation means for modulating the information based on change in the electrification condition detected by the detection means,
• wherein the electrification target is a human body, and
• wherein the detection means detects an electrification condition of an electrification target electrified by the quasi-electrostatic field based on a modulated signal resulted from modulation according to information to be sent so that a relation of r=λ/2π is satisfied where a longest distance between the electric field generation electrode and a detection electrode for detecting the quasi-electrostatic field is taken to r and a wavelength of the modulated signal to be output to the electric field generation electrode is taken to λ.

An electrode manufacturing method of an electrode to be used in communicating a quasi-electrostatic field as an information communication medium, wherein

• a first step of selecting an originating frequency and a communication band for communication, a distance between electrodes and an electrode area of a sender parallel plane electrode to be used as a sender electrode, and a distance between electrodes of a receiver parallel plane electrode to be used as a receiver electrode;
• a second step of determining a communication limit position between the sender parallel plane electrode and the receiver parallel plane electrode based on a matter selected in the first step;
• and
• a third step of determining whether potential exists where a strength induction field component of an electric field at the communication limit position determined in the second step is below a noise floor specified according to the communication band, when potential of the originating frequency is supplied to the sender parallel plane electrode.