Abstract: The present invention provides a radio power converter and a radio communication apparatus in which an environmental electromagnetic wave is efficiently converted into an operation power of a semiconductor integrated circuit by using a coil antenna configured within the semiconductor integrated circuit. The radio communication apparatus converts the received environmental electromagnetic wave into a direct-current voltage and charges a decoupling capacitor with an electric power so as to increase the direct-current voltage. A resonance frequencies of an antenna are changed depending upon a value of the increased direct-current voltages. The antenna sequentially receives environmental electromagnetic waves having different resonance frequencies for thereby increasing the direct-current voltage to a desired direct-current voltage.