Patent ID: 7642618

Claim:
A semiconductor device comprising: a first circuit to modulate a carrier wave by way of a first signal to output a second signal whose frequency is higher than a frequency of said first signal; a second circuit to demodulate a third signal by way of said carrier wave to output a fourth signal whose frequency is lower than a frequency of said third signal; and a third circuit to generate said carrier wave, wherein at least one of said first, second and third circuits includes a first inductor, wherein at least one of the first, second and third circuits other than that including said first inductor includes a second inductor, wherein said first inductor is provided with a first permanently-closed loop wire for reducing an inductive coupling generated through mutual inductance between said first inductor and said second inductor which is provided outside of an enclosure of said first closed loop wire, wherein said second inductor is provided with a second permanently-closed loop wire for reducing an inductive coupling generated through mutual inductance between said second inductor and said first inductor which is provided outside of an enclosure of said second closed loop wire, and wherein each of said first and second permanently-closed loop wires is alternating-current-electrically separated from a ground electric potential.