INFLUENCE OF THE BIASING SCHEME ON THE PERFORMANCE OF AU SRTIO3/LAALO3 THIN-FILM CONDUCTOR/FERROELECTRIC TUNABLE RING RESONATORS/

The performance of gold/SrTiO3/LaAlO3 conductor/ferroelectric/dielectr ic side-coupled, tunable ring resonators at Ku-band frequencies is pre sented. The tunability of these rings arises from the sensitivity of t he relative dielectric constant (epsilon(r)) of SrTiO3 to changes in t emperature and de electric fields (E). We observed that the change in epsilon(r) which takes place by biasing the ring up to 450 V alters th e effective dielectric constant (epsilon(eff)) of the circuit resultin g in a 3 lambda resonant frequency shift of nearly 12% at 77 K. By app lying a separate de bias between the microstrip line and the ring, one can optimize their coupling to obtain high Q bandstop resonators with delta f(n)(-1) = f(o)/Delta f(3dB) as high as 12,000. The 3 lambda re sonance was tuned from 15.75 to 17.41 GHz while keeping delta f(n)(-1) above 768 over this range. The relevance of these results for practic al microwave components will be discussed.