Single phase TiO₂ and CeO₂ were prepared using wet-chemical methods, then as-prepared materials were converted into cylindrical pellets with (8 mm diameter and 1 mm thick) by applying uni-axial pressure of 4 ton using a hydraulic press, then sintered at 300, 450 and 600 ºC for 30 min for TiO₂ sample and for the case of CeO₂ it was done at 300, 600 and 900 ºC for 30 min.

Influence of grain boundary effect on the dielectric properties of nanocrystalline TiO₂ and CeO₂ as a function of applied bias voltages. Since nanocrystals have large number of grain boundary interfaces in which the local atomic arrangements are different from those of the crystal lattice. If the bias voltage is applied more and more, then the suppression of grain boundary potential barrier height can be realized with an apparent reduction in the permittivity values. It was experimentally observed in both the systems for all the crystallite sizes and the percentage of tunability at 100 Hz for 9 nm CeO₂ and 6 nm TiO₂ was found to be ~85%.

Percentage of voltage tunable dielectric constant, tunability (T%) is very high in both the systems, it explores the possibilities of applying these nanocrystals as a potential material for phased array antenna applications.