A semiconductor device includes a low noise amplifier configured to amplify a radio signal from an antenna and output an reception signal, a down converter configured to down-convert the reception signal, a first divider coupled with the down converter, a first local oscillator coupled with the first divider, a modulator configured to modulate a transmission signal, a second divider coupled with the modulator, and a second local oscillator coupled with the second divider. The modulator includes a first inductor of a spiral shape, the local oscillator includes a second inductor of a horse-shape having an opening, and the opening of the second inductor is disposed opposite to the first inductor.