Miniaturized notch antenna based on lanthanum titanium perovskite oxide thin films

• MIM capacitor based on La2Ti2O7 films is used to miniaturize a notch antenna.
• The dielectric constant and loss of La2Ti2O7 films are respectively around 60 and 0.005 at 1 GHz.
• Miniaturization rates of 64.2% and 28.5% are obtained with capacity values of 3.8 pF and 1.5 pF.
• An efficiency of 30% is obtained with the capacitance of 1.5 pF.
• MIM structures based on La2Ti2O7 films are achieved by reactive RF magnetron sputtering.

This paper presents the integration of a dielectric lanthanum titanium oxide compound as thin film in a discrete capacitive component operating at microwaves. The integration in a notch antenna of a MIM (Metal/Insulator/Metal) structure based on this oxide material is numerically and experimentally studied. Oxide films are deposited by reactive magnetron RF sputtering of an La2Ti2O7 target. The films are composed of an unusual phase: the orthorhombic La2Ti2O7 compound, with a textured growth on Pt/Si and Pt/SrTiO3 substrates. Moderate dielectric constant values (Epsilon around 60) and low loss (Tan Delta lower than 0.005) are obtained at 1 GHz. Inserting this original MIM capacitor in the antenna structure results in a shift to a lower value of its operating frequency. This shift, from 885 MHz to 317 MHz, corresponds to a significant size reduction of 64.2%. The measured values are confronted with simulation obtained by numerical software.