Abstract: he Ag₂O-Nb₂O₅-Ta₂O₅ (ANT) system is a novel high frequency high permittivity ceramic material which can be sintered below 1150℃. The doping of Na⁺ can replace A
site ions (Ag⁺) in ANT to form ANNT system. In this paper proper Na⁺ ions were introduced into ANT system. XRD, SEM, and energy spectrum analysis show that proper Na⁺ addition makes the
lattice parameter reduced, i.e. the capacity of octahedron reduced, the dielectric dissipation factor of the system is improved efficiently because of depression of relaxation polarization of Nb⁵⁺, and
the dielectric properties of the system are as follows: ε>500, tgδ≤5×10^-4,
α_c=+12ppm/℃,ρ_v>1012Ω·cm.

Key words: high frequency high permittivity, ANT, relaxation polarization, dissipation factor