Formulation and Characterization of Sinterless Barium Strontium Titanate (BST) Dielectric Nanoparticle Ink for Printed RF and Microwave Applications

Here, we report a previously unreported low-temperature curable barium strontium titanate (BaXSr1-XTiO3) or BST dielectric nanoparticle ink which shows a high dielectric tunability for printed electronics/additive manufacturing applications. The newly formulated BST ink is optimized to print in aerosol jet printers and can be cured at 150 degrees C, which will allow the fabrication of tunable radio-frequency (RF) and microwave (MW) devices on a wide range of flexible substrates. Characterization of high-frequency dielectric properties showed a high dielectric tunability (similar to 15% at 10 GHz with 10 V/mu m) and a high dielectric constant (similar to 16 at 10 GHz). The linear-reversible tunability, which is very important for tunable devices, was confirmed by the tunability testing at 10 GHz. Characterization of temperature-dependent dielectric properties found < 10% variations of the dielectric constant at 10 GHz from -50 degrees C to 125 degrees C for this BST ink. Detailed information on BST nanoparticle characterization, ink formulation and characterization of dielectric properties is discussed.