Development of high quality factor microwave ceramics for application in wireless high temperature patch antenna sensor

Abstract

The microwave dielectric properties of (Mg0.93Zn0.07)2SnO4 ceramics were examined with a view to their exploitation for wireless high temperature patch antenna sensor. The (Mg0.93Zn0.07)2SnO4 ceramics were prepared by the conventional solid-state method with various sintering temperatures. The X-ray diffraction patterns of the (Mg0.93Zn0.07)2SnO4 ceramics revealed no significant variation of phase with sintering temperatures. Specimens were not single-phase, small amounts of SnO2 as the second phase were observed in all specimens. A dielectric constant ( $${\varepsilon _r}$$ ) of 8.3, a quality factor (Q × f) of 171,300 GHz (at 17.5 GHz), and a temperature coefficient of resonant frequency ( $${\tau _f}$$ ) of − 69 ppm/°C were obtained for (Mg0.93Zn0.07)2SnO4 ceramics that were sintered at 1550 °C for 4 h. The developing procedures and test results for patch antenna temperature sensor composed of (Mg0.93Zn0.07)2SnO4 ceramics were recorded. The test results included the variation of frequency over operating temperature range, sensitivity, return loss, and 3 dB bandwidth. The resonating frequency, return loss, and 3 dB bandwidth measured at 20 °C were 2.48 GHz, − 15.0 dB and 63 MHz, respectively. A sensitivity of − 0.17 MHz/°C was successfully achieved.