  Radio-based detection of high-energy particles is growing in maturity. In
this chapter, we focus on the detection of neutrinos with energies in excess of
10 PeV that interact in the thick, radio-transparent ice found in the polar
regions. High-energy neutrinos interacting in the ice generate short duration,
radio-frequency flashes through the Askaryan effect that can be measured with
antennas installed at shallow depths. The abundant target material and the long
attenuation lengths of around 1 km allow cost-effective instrumentation of huge
volumes with a sparse array of radio detector stations. This detector
architecture provides sufficient sensitivity to the low flux of
ultra-high-energy neutrinos to probe the production of ultra-high-energy cosmic
rays whose origin is one of the longest-standing riddles in astroparticle
physics. We describe the signal characteristics, propagation effects, detector
setup, suitable detection sites, and background processes. We give an overview
of the current experimental landscape and an outlook into the future where
almost the entire sky can be viewed by a judicious choice of detector
locations.
