• A novel high-entropy ceramic (Mg0.5Zn0.5)0.4+xLi0.4(Ca0.5Sr0.5)0.4−xTiO3 was synthesized via solid-phase method, achieving near-zero τf (−8.6 ppm/°C) at x=0.35.
• The ceramics exhibit excellent microwave dielectric properties: εr = 17.6, Q×f = 40900 GHz, making them promising for wireless communication.
• The secondary phase Ca0.5Sr0.5TiO3 and [TiO6] octahedral distortion critically influence dielectric properties, providing a design strategy.
• This work demonstrates that high-entropy engineering can effectively tailor temperature stability and performance of microwave dielectrics.