A fully distributed non linear waveguide using (Pb,Sr)TiO3 thin film: Second and third harmonics generation.

We report on the experimental investigation of a non-linear (NL) Co-Planar Waveguide (CPW) fabricated by means of a ferroelectric film. In contrast to conventional NL-CPW, periodically loaded by lumped varactors, the tunable ferroelectric material is fully distributed along the propagation direction and the transmission line does not intrinsically exhibit Bragg cutoff. The experimental demonstration is carried out by means of a 160 nm-thick Pb0.4Sr0.6TiO3 ferroelectric film voltage-controlled via the 1 μm-slot of a CPW transmission line. In a first stage, complex dielectric constant has been retrieved from scattering parameters measurements up to 60 GHz and for a bias voltage ranging from 0 to 30 V. High performances in terms of tunability have been found by a relative permittivity change under 30 V as high as 60% in the overall frequency band. Subsequently, the tunable ferroelectric CPW was used for second and third harmonics generation for a fundamental at centimeter wavelengths. While for low dc-voltage, third harmonic generation is dominant, it is found a main harmonic generation of rank 2 at higher dc bias voltage in agreement with the symmetry properties of the C(V) characteristics. [ABSTRACT FROM AUTHOR]