La(Mg0.5−xMexSn0.5)O3-based (Me = Ca, Sr) dielectric resonator antenna for use in a wireless high-temperature sensor

• Published in: Journal of the Ceramic Society of Japan 2019/09/01, Vol.127(9), pp.617-626
• Main Authors: CHEN, Yih-Chien, YOU, Yu-Cheng
• Format: Article
• Language: English
• Subjects: Dielectric properties; Raman scattering; Temperature sensor; X-ray diffraction
• ISSN: 1882-0743; 1348-6535
• DOI: 10.2109/jcersj2.19061

The microwave dielectric properties of La(Mg0.5−xMexSn0.5)O3 (Me = Ca, Sr) ceramics are studied, in order to develop a wireless dielectric resonator antenna temperature sensor. The microwave dielectric properties of La(Mg0.5−xMexSn0.5)O3 (Me = Ca, Sr) ceramics are determined using X-ray diffraction patterns, Rietveld refinement patterns, Raman spectra, and by observing the microstructures. La(Mg0.5−xMexSn0.5)O3 (Me = Ca, Sr) ceramics are prepared using a conventional solid state method. As the degree of substitution of Ca2+ and Sr2+ increases, the position of the A1g(O) Raman mode shifts toward a lower frequency. The La(Mg0.4Ca0.1Sn0.5)O3 ceramic exhibits a minimum full width at half maximum for the A1g(O) Raman vibration mode in the series of La(Mg0.5−xMexSn0.5)O3 (Me = Ca, Sr) ceramics. La(Mg0.49Ca0.01Sn0.5)O3 ceramics that were sintered at 1600°C for 4 h have an apparent density of 6.57 g/cm3, a dielectric constant (εr) of 19.9, a quality factor (Q×f) of 94,300 GHz, and a temperature coefficient at the resonant frequency (τf) of −87 ppm/°C. The development process and test results for a dielectric resonator antenna temperature sensor that uses La(Mg0.49Ca0.01Sn0.5)O3 ceramics are recorded. The resonant frequency is 9.35 GHz and the 3 dB bandwidth measured at room temperature is 6.4 MHz. A sensitivity of −1.03 MHz/°C is achieved.