A porous core Zeonex THz fiber with low loss and small dispersion

•The fiber features a low propagation loss ranged from 0.0180 to 0.0345 cm−1, in the frequency regime of 0.3–0.5 THz with diameter of 3 mm.•There is a flat and near-zero dispersion band in the range of 0.39 to 0.45 THz with a value of −0.285 ± 0.02 ps/THz/cm.•The experimental resultsare in good agreement with the simulated results.•The absolute variation of air hole fraction in core and cladding is 0.485% and 1.657% respectively, which indicates the reliability of fabrication with low deformation.