In this research work, we report a new design model of quasi-shaped cladding areas with rotated-hexa-based elliptical shaped core areas in photonic crystal fiber (Q-PCF) for terahertz waves of communication signals. Here, we present a six-layer circular air hole in the quasi-shape of cladding regions with two layers of rotated-hexa-based elliptical shaped air holes in the core regions of the Q-PCF for analysis of communication networks in the terahertz regime. Additionally, perfectly matched layers and the finite element method based on the COMSOL software are used to design this Q-PCF. For short- and wideband communication sectors, our proposed Q-PCF is highly useful, as it reduces ultralow effective material loss (EML), confinement loss, and scattering loss in the terahertz regime. After analysis of the numerical results, our suggested Q-PCF shows an ultralow EML of 0.0159 cm⁻¹, power fraction in the core area of 74%, large effective area of 5.49 × 10^–8 m², confinement loss of 3.22 × 10^–12 cm⁻¹, and scattering loss of 1.23 × 10^–10 at 1 THz frequency. Moreover, our proposed Q-PCF demonstrates single-mode propagation by the graphical results of the V-parameter over a frequency range of 0.80–3 THz. Our results suggest, we can clearly say that the reported Q-PCF may be highly appropriate for terahertz wave propagation for many communication networks.