Frequency agile filters based on SrTiO3/YBa2Cu3O7 heterostructures grown by PLD on LaAlO3 substrates

Passive devices using high temperature superconductors are already going to be implemented in electronics for passive filtering in telecommunications. To avoid the frequency jamming not only in terrestrial and satellite communications but also in the radar frequency ranges, filter agility is essential to undertake further development. We will discuss here the interest of using SrTiO3 as tunable oxide for agile devices and present our last results on voltage agile microwave resonator fabricated from YBa2Cu3O7/SrTiO3 heterostructures. A strong correlation is found between Q(0) or agility and the tetragonal distortion of the SrTiO3 layer. The resonator performance is markedly increased by associating growth parameter optimization and ex situ annealing of SrTiO3 layer prior to the YBa2Cu3O7 deposition. Annealed samples exhibit almost voltage independent losses of about 5 x 10(-3) at 6 GHz and 77 K, with epsilon(r) at 1200 showing a variation of greater than or equal to50% at 10(5)V/m.