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

In this paper, ferroelectric ceramics with (Sr2Ta2O7)(100)(-x)(La2Ti2O7)(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) with a permittivity of 83 and losses tan delta = 5 x 10(-3)@3.3 GHz. The DRA prototype was simulated, produced and tested. It exhibits a hybrid HEM11 delta mode, with a resonant frequency at 5.80 GHz, a 4.9% bandwidth and a gain of 6.4 dB. These features confirm the potential of the paraelectric STLTO compositions in compact antennas radiating at frequencies below 6 GHz. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the dielectric properties of ferroelectric ceramics STLTO with different chemical compositions, and successfully integrates them in Dielectric Resonator Antennas (DRA). The experimental results demonstrate that the chemical composition of synthesized STLTO ceramics significantly affects their dielectric performance, and the simulation of the antenna prototype shows the radiation potential of STLTO at lower frequencies.