<p>This study presents a comprehensive analysis of isotropic plasma-wrapped circular waveguides filled with lithium fluoride (LiF) in the THz frequency regime. The influence of various parameters on waveguide performance has been analyzed. Transfer matrix technique is utilized to obtain the characteristics equation. Numerical results demonstrate how the normalized propagation constant and phase velocity respond to changes in plasma frequency and radius of the waveguide for modes m = 0 and m = 1. The propagation constant shows a strong dependency on both the plasma frequency and the waveguide radius, indicating significant tuning capability for THz waveguide applications. Moreover, mode m = 0 supports higher frequency compared to mode m = 1. Furthermore, plasma frequency and waveguide radius are extremely sensitive to phase velocity. The THz frequency fluctuations provide an extra degree of freedom to modulate and control surface plasmon polaritons (SPPs) for the proposed waveguide structure. These findings are critical for the development of optimized plasmonic devices and advanced optical communication systems in the THz frequency regime.</p>