No abstract

Dielectric properties of Ba 0 5 Sr 0 5 TiO 3 (BST-0.5) polycrystalline thin films, deposited on alumina substrates by means of reactive Pulsed Laser Deposition (PLD), were measured at GHz frequencies using an interdigital capacitor (IDC). By applying a voltage up to 40 V between the two groups of fingers at room temperature, a high tunability of 27% was achieved at 5 GHz. A relative dielectric constant of 500 (consistent with the low-frequency IDC measurements) has been obtained using coplanar wave guides by means of the Through-Reflect-Line (TRL) analysis combined with either a conformal mapping model or a full wave calculation. The BST loss tangent was estimated as 0.05 in the range 3-16 GHz.