Development of Tunable Ferroelectric Ceramic Capacitors

Abstract

Ferroelectric perovskite ceramics with a high dielectric constant, low loss, high tunability, and high electric breakdown are ideal for nonlinear transmission lines (NLTLs) to generate radio frequency (RF) signals at high-power levels. To achieve the required properties, a comprehensive study of the material phase transitions and the optimal ratio adjustment between the chemical elements in the perovskite crystal structure is required. The advancement of this solid-state technology is the most promising optimization for NLTLs in developing high-power (>100 MW) devices with high tunability (>60%) and high repetition rate (>1 kHz) for soliton generation. The barium strontium zirconium titanate (BSZT) ceramic compositions were synthesized and characterized to maximize material tunability. The composition Ba0.97Sr0.03Zr0.2Ti0.8O3 exhibited a high permittivity (>12200), low loss tangent (< 0.01), and an exceptional tunability of the order of 79% at an electric field of 10 kV/cm near the phase temperature transition at 300 K. Ferroelectric ceramic is an outstanding material with promising characteristics for producing RF signals in an NLTL, and here, the BSZT is considered for this application.