Breaking Symmetry Enables Tunable Low-Loss Microwave Dielectric

Breaking symmetry to enable tunable, low-loss microwave dielectrics lies at the heart of a study that could redefine varactor design. Researchers focus on dielectric materials whose properties can be tuned by electric fields without sacrificing microwave performance, a balance crucial for wireless communications and radar systems. Among candidates, Ruddlesden-Popper (RP) phase dielectrics are prized for their inherently low losses, yet their crystallographic symmetry has limited integration with out-of-plane, parallel-plate architectures. The team breaks this symmetry by inserting a Ba0.45Sr0.55O rock-salt layer between every n perovskite unit cells, aligning the film with conventional device geometry.