Abstract: The present disclosure describes a strained dielectric material comprising at least one type of component containing a domain wall variant pattern, or superdomain structure, that is in phase-co-existence with, or in close phase proximity to, a paraelectric state achieved at zero electric field or over a finite range of non-zero electric field, wherein the at least one type of component comprises one or more of an in-plane sub-domain polarization component, a plane-normal sub-domain polarization component, or a solid solution of a ferroelectric.

Abstract: Parallel plate tunable varactors having a bulk capacitance contribution to a total capacitance increased compared to a fringing capacitance contribution are disclosed. The contribution of the bulk capacitance to the total capacitance of an exemplary BST varactor is increased by increasing the area/perimeter ratio of the active region, thereby improving the tunability and other properties of the varactor. In an exemplary embodiment, an active region of the varactor has a lateral shape with a perimeter that is less than a perimeter of an equivalent area square. In various exemplary embodiments, the shape of the active region may be substantially circular or substantially octagonal. Methods for fabricating and designing such varactors are also disclosed.