<p>This paper presents a phononic crystal structure designed to control transverse wave propagation by incorporating periodically arranged locally resonant beam units within hollowed-out regions of a long tape tether. The low-frequency bandgap characteristics of this structure are systematically investigated through a combination of finite element analysis and experimental validation. Firstly, the bandgap formation mechanism is explored in detail based on an idealized infinite periodic phononic crystal model, with a focus on band structure analysis and local resonance modes. This theoretical foundation provides insights into the underlying physics governing vibration attenuation. Moreover, the effect of tether bending on the bandgap characteristics is also considered. Subsequently, the influence of key structural parameters on the low-frequency bandgap properties is systematically examined. Finally, numerical simulations and experimental tests are conducted on a finite phononic crystal structure to verify its effectiveness in suppressing transverse wave propagation. The results demonstrate the significant potential of this design for enhancing the stability of the tape tether in tethered satellite systems, offering a promising approach for vibration control in engineering applications.</p>