  We calculate the solar-modulated energy spectra of cosmic-ray antiprotons
($\bar{p}$'s) from two candidate primary sources, i.e., evaporating primordial
black holes and the annihilation of neutralino dark matter, as well as for the
secondary $\bar{p}$'s produced by cosmic-ray interactions with interstellar
gas. A large enhancement toward the solar minimum phase emerges in the
low-energy flux of $\bar{p}$'s from the primary sources, whereas the flux of
the secondary $\bar{p}$'s, falling steeply below 2 GeV, does not significantly
vary. This enables us to conduct a very sensitive search for primary $\bar{p}$
components by precisely measuring the $\bar{p}$ spectrum, especially at low
energies, throughout the forthcoming solar minimum phase.
