An air-filled parallel-plate capacitor with plate separation \(d\) has a maximum sustainable operating voltage of \(V_0\), determined by the dielectric strength \(E_{\text{air}}\). The space between the plates is then completely filled with a solid dielectric material having dielectric constant \(\kappa = 3\) and dielectric strength \(E_{\text{mat}} = 2 E_{\text{air}}\). What is the new maximum operating voltage that the capacitor can sustain without dielectric breakdown?