  $\textit{Context.}$ The magnetized Solar System planets are strong radio
emitters and theoretical studies suggest that the radio emission from nearby
exoplanets in close-in orbits could reach intensity levels $10^{3}-10^{7}$
times higher than Jupiter's decametric emission. Detection of exoplanets in the
radio domain would open up a brand new field of research, however, currently
there are no confirmed detections at radio frequencies.
  $\textit{Aims.}$ We investigate the radio emission from Jupiter, scaled such
that it mimics emission coming from an exoplanet, with low-frequency
beam-formed observations using LOFAR. The goals are to define a set of
observables that can be used as a guideline in the search for exoplanetary
radio emission and to measure effectively the sensitivity limit for LOFAR
beam-formed observations.
  $\textit{Methods.}$ We observe "Jupiter as an exoplanet" by dividing a LOFAR
observation of Jupiter by a down-scaling factor and adding this observation to
beam-formed data of the "sky background". Then we run this artificial dataset
through our total intensity (Stokes-I) and circular polarization (Stokes-V)
processing and post-processing pipelines and determine up to which down-scaling
factor Jupiter is still detected in the dataset.
  $\textit{Results.}$ We find that exoplanetary radio bursts can be detected at
5 pc if the circularly polarized flux is $10^5$ times stronger than the typical
level of Jupiter's radio bursts during active emission events
($\sim4\times10^{5}$ Jy). Equivalently, circularly polarized radio bursts can
be detected up to a distance of 20 pc (encompassing the known exoplanets 55
Cnc, Tau Bo\"{o}tis, and Upsilon Andromedae) assuming the level of emission is
$10^{5}$ times stronger than the peak flux of Jupiter's decametric burst
emission ($\sim6\times10^{6}$ Jy).
