Local lattice distortion induced by (Sn0.5W0.5)5+ complex doping enables near‑zero τf and suppressed dielectric loss in ZnZrNb2O8 ceramics for 28GHzmm‑wave antenna

The 28 GHz band is central to 5 G/6 G millimeter-wave communications, demanding dielectric ceramics with moderate permittivity, ultra-high quality factor, and near-zero temperature coefficient of resonant frequency. Here we report a local rattling strategy using (Sn 0.5 W 0.5 ) 5+ complex doping at the Nb site in wolframite ZnZrNb 2 O 8 . ZnZrNb 2- x (Sn 0.5 W 0.5 ) x O 8 ( x = 0, 0.02, 0.04, 0.06) ceramics were prepared by a conventional solid-state reaction and sintered at 1225–1250 °C. Despite complete solid solubility without secondary phases, the ionic radius and charge mismatch creates local lattice strain. This local distortion tunes τ f from −31.2 ppm/°C ( x = 0) to +1.4 ppm/°C ( x = 0.04), achieving near-zero temperature compensation, and increases Q × f from 78,000 to 99,200 GHz at x = 0.04. The optimal ceramic was used to fabricate a 28 GHz patch antenna, which exhibits a radiation efficiency of 91%, a gain of 6.7 dBi, and a resonant frequency drift of only ± 1.3 MHz from −30 to +80 °C. These results establish local rattling engineering as a new design paradigm for mm-wave communication components.