Tagantsev, A. K.Astafiev, K. F.2006-08-212006-08-212006-08-21200110.1080/10584580108011948https://infoscience.epfl.ch/handle/20.500.14299/233470WOS:000173066800028A strong de electric field dependence of the dielectric permittivity makes perovskite ferroelectrics promising materials for tunable microwave devices like phase shifters, tunable resonators, tunable filters etc. Dielectric loss is a crucial parameter for these applications. It has been recently realized that the so-called quasi-Debye loss mechanism related to local or global violation of central symmetry of materials plays a important;.,I the total balance of microwave loss. This mechanism controls the increasing dc field dependence of microwave loss in high-quality ferroelectric materials. The present paper reports on modeling oil the quasi-Debye loss mechanisms in SrTiO3 and KTaO3 systems. it is concluded that the contribution of this mechanisms is large enough to affect the performance of ferroelectric-based tunable microwave devises.ferroelectricsdielectric lossmicrowavetunable devicesdielectric losscrystalsdielectric losstext::journal::journal article::research article