Perovskite (Sr2Ta2O7)100−x(La2Ti2O7)x ceramics: From dielectric characterization to dielectric resonator antenna applications

Abstract

In this paper, ferroelectric ceramics with (Sr 2 Ta 2 O 7 ) 100-x (La 2 Ti 2 O 7 ) x (STLTO) compositions have been investigated and their dielectric properties have been characterized in wide frequency band (from few kHz to few GHz); their integration in Dielectric Resonator Antennas (DRA) was conducted. The dense STLTO ceramics have been obtained by high temperature sintering of powders synthetized by solid state chemistry route. STLTO crystalline cell parameters and volume vary linearly as a function of the chemical composition (x) thus demonstrating an ideal solid solution domain for 0 ≤ x ≤ 3. Dielectric characterizations highlight that the permittivity and the dielectric loss vary according to the composition (x) and that the lowest losses are obtained for x < 1.65 compositions. The latter corresponds to the transition between the ferroelectric and paraelectric compositions of the STLTO material at room temperature. A low profile DRA structure was realized using a cylindrical paraelectric STLTO resonator (with x = 0

Graphene oxide microstrip antenna-based sensor for oxygen gas sensing in medical applications

“…These modes displacement to the right as the O 2 concentration increases, whereas this change observed in the frequency could be explained by the variation of resistance of GO film when there is an interaction of the O 2 with graphene on the GO surface, taking the alteration of the device impedance and resulting the displacement of its frequency of operation [36,37]. In addition, it was observed that the reflection coefficient (S 11 ) also increased with the O 2 concentration but remained below −10 dB, which is a requirement for a device operating as an antenna [38,39]. This result is important because it demonstrates that the device evaluated act as an antenna at the O 2 elevated concentrations.…”

Tunable TTB strontium and tantalum based thin films: Influence of the deposition parameters on the structural and dielectric properties

“…We have demonstrated the ferroelectric behavior of the p-STLTO family of compounds in the form of ceramics for (Sr2Ta2O7)100-x(La2Ti2O7)x compositions with x ranging from 0 to 5 [7]. Optimal characteristics were achieved for x = 1.65: the permittivity value was ' = 375 with a high tunability T = 55 % at 30 kV/cm, 10 kHz and room temperature [8], associated to low dielectric losses tan = 2.10 -3 . Our work then focused on the transfer of the specific composition corresponding to x = 1.65 in the thin films form.…”

High-Entropy Lead-Free Perovskite Bi0.2K0.2Ba0.2Sr0.2Ca0.2TiO3 Powders and Related Ceramics: Synthesis, Processing, and Electrical Properties

“…These materials are renowned for their broad spectrum of multifunctional properties, including ferroelectricity, piezoelectricity, pyroelectricity, ferromagnetism, and nonlinear dielectric characteristics [2][3][4][5][6]. Such diverse properties make them suitable for a variety of applications, encompassing energy conversion and storage, sensors, filters, separators, detectors, antennas, and environmental remediation [7][8][9][10][11][12][13].…”