Initialization of a semiconductor device can be efficiently performed, which transmits and receives data through wireless communication. The semiconductor device includes an antenna, a power source circuit, a circuit which uses a DC voltage generated by the power source circuit as a power source voltage, and a resistor. The antenna includes a pair of terminals and receives a wireless signal (a modulated carrier wave). The power source circuit includes a first terminal and a second terminal and generates a DC voltage between the first terminal and the second terminal by using a received wireless signal (the modulated carrier wave). The resistor is connected between the first terminal and the second terminal. In this manner, the semiconductor device and the wireless communication system can transmit and receive data accurately.