We propose various designs of porous polymer fibers for guiding terahertz radiation. Numerical simulations are
presented for three fiber geometries: a Bragg fiber consisting of periodic multilayers of ferroelectric polyvinylidene
fluoride (PVDF) and polycarbonate (PC), a sub-wavelength waveguide containing multiple sub-wavelength holes, as
well as a cobweb-like porous Bragg fiber consisting of solid film layers suspended by a network of bridges. Various
properties of these fibers are presented. Emphasis is put on the optimization of the geometries to increase the fraction of
power guided in the air, thereby alleviating the effects of material absorption. Losses of about 10 dB/m, 7.8 dB/m, and 1.7 dB/m at 1 THz are respectively predicted for these three structures.