A quantum device includes: a substrate; and at least three co-planar structures arranged on a surface of the substrate, each co-planar structure, of the at least three co-planar structures, including a superconductor, in which a first effective dielectric constant between a first co-planar structure and a second co-planar structure that is a nearest neighbor to the first co-planar structure is above a first threshold, a second effective dielectric constant between the first co-planar structure and a third co-planar structure that is a next nearest neighbor to the first so-planar structure is less than a second threshold, and the second threshold is less than the first threshold.