Patent ID: 8884470

Claim:
A semiconductor device comprising: an antenna circuit; a voltage detection circuit comprising: a first transistor including a first terminal and a second terminal; and a resistor including a first terminal and a second terminal, the first terminal of the resistor being electrically connected to the second terminal of the first transistor; a first capacitor including a first terminal electrically connected to the second terminal of the first transistor and the first terminal of the resistor, and a second terminal electrically connected to a wiring; and a resonance frequency regulating circuit comprising: a second capacitor including a first terminal electrically connected to a first terminal of the antenna circuit; and a second transistor including a first terminal electrically connected to a second terminal of the second capacitor, a second terminal electrically connected to a second terminal of the antenna circuit, and a gate electrically connected to the first terminal of the first capacitor and the voltage detection circuit.