  We investigate various methods for extending the simple analytical capillary
model to describe the dispersion and loss of anti-resonant hollow-core fibers
without the need of detailed finite-element simulations across the desired
wavelength range. This poor-man's model can with a single fitting parameter
quite accurately mimic dispersion and loss resonances and anti-resonances from
full finite-element simulations. Due to the analytical basis of the model it is
easy to explore variations in core size and cladding wall thickness, and should
therefore provide a valuable tool for numerical simulations of the ultrafast
nonlinear dynamics of gas-filled hollow-core fibers.
