Epitaxial strontium titanate (SrTiO 3 or STO) thin films were prepared by an off-axis pulsed laser deposition technique on neodymium gallate (NdGaO 3 or NGO) substrates held at temperature of 820°C. This technique allows different film growth rates in a deposition. Coplanar capacitors were fabricated and dielectric responses were measured at 1MHz and at 2GHz, and from 300K to 4K. The electric field tunability of the dielectric constant and loss tangent were taken with a range of electric field. The structure and morphology of the films were analyzed using high-resolution X-ray diffractometry and atomic force microscopy, respectively. The results showed that the films are crystalline with (100) orientation and the grains are columnar. Increased in-plane grain size and reduced surface to volume ratio were found to play a major role in improved performance of the film coplanar capacitors. The film with the growth rate of approximate 40Å/min showed the highest change in the dielectric constant with an electric field of 4V/μm. The film also showed the largest in-plane grain size of about 3000Å.