<p>To address the high energy threshold and limited applicability of traditional nonlinear energy sinks (NES) for suppressing microvibrations in continuous medium structures, this paper introduces a negative stiffness mechanism into the conventional cubic stiffness NES, forming a bistable nonlinear energy sink (BNES). The study focuses on satellite solar panels, which are simplified as a cantilever beam coupled with a nonlinear energy sink at its free end to reduce microvibrations. The nonlinear restoring force of the BNES is derived, and the dynamical equations of the coupled system are established. Using the Galerkin approximation, a reduced-order model is obtained, and the stability of equilibrium points is analyzed through the Jacobian matrix. The slow-motion manifold is derived using the method of averaging and multiscale analysis. The response characteristics of the bistable nonlinear energy sink (BNES) under various external excitations are explored, demonstrating its effectiveness in microvibration suppression. The strongly modulated response (SMR) is shown to be superior in suppressing microvibrations in terms of displacement response, maximum amplitude, and energy transfer. Bifurcation analysis, including saddle-node (SN) bifurcations and Hopf bifurcations, is conducted to understand the system's dynamic behavior. The effects of parameters such as stiffness and damping on SMR thresholds are systematically investigated, leading to an optimal parameter design. A comparison of linear and nonlinear damping effects on SMR thresholds is also provided. The results indicate that the BNES effectively generates SMR, ensuring superior microvibration suppression in flexible beams.</p>