  Roebel cables made of HTS coated conductors are regarded as promising cables
for winding applications in virtue of their large engineering current density
and low losses. The composing meander-shaped strands are assembled very tightly
into the cable, which results in a strong electromagnetic interaction between
them. This interaction profoundly influences the effective self-field critical
current ($I_c$) of the cable, which is much lower than the sum of the $I_c$s of
the composing strands. Also the AC losses are influenced by the material's
properties and by the geometrical configuration of the cable. Being able to
predict the effective critical current and AC losses of such cables is very
important for a proper design of applications: due to the complexity of the
cable's geometry and of the material's properties, this prediction can only be
performed with advanced numerical tools.
  In this contribution we use finite-element-based models to compute the
effective $I_c$ and the AC losses of Roebel cables composed of 31 strands using
tapes from two manufacturers. The AC losses are analyzed in the simultaneous
presence of transport current and background perpendicular field proportional
to the current, which mirrors the situation occurring in a winding. Our models
include the angular dependence of $J_c(B,\theta)$ at~77 K, which is very
different for the two materials.
  By means of a successful comparison of the simulation results to experimental
data obtained with a calorimetric method measuring the evaporation of liquid
nitrogen, this work confirms the applicability and efficiency of our numerical
techniques for simulating the electromagnetic behavior of Roebel cables and
devices thereof.
