Improving microwave dielectric properties of La2.98/3Sr0.01(Mg0.5Sn0.5)O3 ceramics with CuO additive

► 0.75 wt% CuO-doped La2.98/3Sr0.01(Mg0.5Sn0.5)O3 had dielectric constant of 20.07. ► 0.75 wt% CuO-doped La2.98/3Sr0.01(Mg0.5Sn0.5)O3 had Q × f of 63,000 GHz. ► 0.75 wt% CuO-doped La2.98/3Sr0.01(Mg0.5Sn0.5)O3 had τf of −77.0 ppm/°C.