Components of electromagnetic waves originating in electronic devices, communication devices, etc., which are unnecessary for operation of those devices, are referred to as electromagnetic noise. When electromagnetic noise interferes with peripheral electronic devices, communication devices, etc., it causes those devices to malfunction and/or degrades their performance.
In recent years, with the increasing popularity of electric vehicles and the miniaturization, densification, and higher frequency of electronic devices, the density of electromagnetic energy is increasing. As a result, measures to lower electromagnetic noise are gaining ever more attention.