This paper proposes a simple design of a broadband terahertz (THz) metamaterial absorber based on the phase-transition properties of vanadium dioxide (VO₂). The compact three-layer architecture comprises a VO₂ resonator, a SiO₂ dielectric spacer, and an Au reflector to achieve broadband absorption. Rather than relying on multiple resonant elements, the proposed design exploits the tunable electrical conductivity of VO₂ in combination with impedance matching to achieve efficient absorption over a wide frequency range. At an electrical conductivity of 200,000 S/m, the absorber exhibits an absorptance exceeding 90% over the frequency range from 3.16 to 8.87 THz, corresponding to a fractional bandwidth (FBW) of 94.93%. Furthermore, the absorption level can be continuously tuned by varying the electrical conductivity of VO₂ from 200 to 200,000 S/m, with the peak absorptance ranging from 4.45% to nearly 97%. High absorptance is maintained for oblique incidence angles of up to 45° under transverse electric (TE) polarization and 60° under transverse magnetic (TM) polarization. The absorption performance is also independent of the polarization state of the incident wave. These characteristics highlight the potential of the proposed design for applications in the terahertz frequency range.