We fabricated a type of superconducting heterostructures, TiN/tapering/NbN/tapering/TiN, on c-cut sapphire substrates by reactive magnetron sputtering. The goal is to achieve an x-band resonator that maintains a high Q in modest magnetic fields. The structure shows (111) orientation with local epitaxial correlation, as a result of stacking face-centered-cubic structures on top of hexagonal-closepacking substrates. The artificial tapering layers vary gradually from NbN into TiN and vice versa, creating a smooth transition so that no distinct interface exists. We characterized microstrip single line resonators on these heterostructures that are promising candidates for quantum information processing with hybrid nuclear-electron spins.