Ferroelectric films: nonlinear properties and applications in microwave devices

Dielectric properties (ε, tanδ) of single crystal SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , (STO) films at microwave frequencies (3GHz and 10GHz) and low frequency (1MHz) were under investigation. The intermodulation distortion measurements at frequency 2 GHz were carried out in microstrip resonator containing STO film planar capacitor. Formulas required to choose the most suitable ferroelectric materials and to design the tunable microwave devices (filters, phiase-shifters) are derived. Phase-shifter based on STO films with figure of merit 70 deg/l dB operating in the frequency range (9.2 - 10.2)GHz at T = 77 K is presented.