In this research, we have suggested an umbrella-shaped cladding and slotted core photonic crystal fiber (PCF). The aimed PCF has been quantitatively inquired employing the full vectorial finite-element method (FV-FEM) at a broader span of frequency of 0.8–2.4 THz. The core region is arranged by rectangular slots and elliptical slots. Where rectangular slots are conformed to high-resistivity silicon (HRS) material and elliptical slots filled with epsilon near zero (ENZ) material. Cyclic olefin copolymer (TOPAS) was applied as the background material. PCF shows enormously eminent birefringence of 6.10 × 10–1, low confinement loss of 3 × 10–9 dB/m, low effective material loss (EML) of 0.129 cm−1, power fraction of 65.1% and scattering loss of 1.23 × 10–10 dB/km at a frequency of 1 THz. The effective area of 9.20 × 10–9 m2, the nonlinearity of 9.56 W−1 km−1 and the V-parameter have also been investigated at 1 THz. A lower dispersion was achieved where the value of X-Axis is near zero and the value of Y-Axis is also near zero and flattened. The aimed PCF can be used for different optical communication systems under the terahertz regime.