  The search for exoplanets in the radio bands has been focused on detecting
radio emissions produced by the interaction between magnetized planets and the
stellar wind (auroral emission). Here we introduce a new tool, which is part of
our MHD stellar corona model, to predict the ambient coronal radio emission and
its modulations induced by a close planet. For simplicity, the present work
assumes that the exoplanet is stationary in the frame rotating with the stellar
rotation. We explore the radio flux modulations using a limited parameter space
of idealized cases by changing the magnitude of the planetary field, its
polarity, the planetary orbital separation, and the strength of the stellar
field. We find that the modulations induced by the planet could be significant
and observable in the case of hot Jupiter planets --- above 100% modulation
with respect to the ambient flux in the $10-100~MHz$ range in some cases, and
2-10% in the frequency bands above $250~MHz$ for some cases. Thus, our work
indicates that radio signature of exoplanets might not be limited to
low-frequency radio range. We find that the intensity modulations are sensitive
to the planetary magnetic field polarity for short-orbit planets, and to the
stellar magnetic field strength for all cases. The new radio tool, when applied
to real systems, could provide predictions for the frequency range at which the
modulations can be observed by current facilities.
