Design and Testing of Miniaturized Dual-Band Microstrip Antenna Sensor for Wireless Monitoring of High Temperatures

To meet the requirements for multiband wireless monitoring of high-temperature parameters faced in areas, such as industrial Internet, aerospace, and energy extraction, a wireless passive miniaturized dual-band microstrip antenna sensor for real-time temperature monitoring is proposed. Based on the meandering technology, a new sensing structure with a size reduction of more than 24% was obtained by designing a dumbbell-shaped slot structure around the edge of rectangular radiating element to increase its surface equivalent current path. The sensor manufacturing was achieved by integrating high-temperature resistant platinum sensitive structures onto alumina ceramics to adapt to temperature measurement in harsh environments, such as high temperature, oxidation, and corrosion. An interrogation antenna is designed that combines miniaturization, broadband, and high-temperature resistance, achieving wireless transmission of sensor dual-band signals. The test results showed that the resonant frequencies of the dual-band microstrip antenna sensor are 2.02 and 2.58 GHz, respectively, which are consistent with the simulation result; both resonant frequencies can characterize the temperature parameter well at 25 °C–800 °C, with a maximum sensitivity of 148.86 kHz/°C, the repeatability standard deviation of less than 0.6 MHz, and fitting error of less than 1 ‰ at different temperatures. The designed dual-band microstrip antenna sensor has excellent performance and can meet the needs of multifrequency band wireless sensing in practical harsh application scenarios.