High Sensitivity SIW-CSRR Temperature Sensor Based on Microwave Scattering

Aiming at the real-time monitoring requirements of equipment temperature in harsh environments such as ultrahigh temperature, high-spin and multi-metal, a wireless passive high-sensitivity temperature sensor with semicircular complementary split resonant ring (CSRR) structure, based on the principle of microwave scattering, was designed by using substrate integrated waveguide (SIW) and high frequency structure simulator (HFSS) electromagnetic simulation software, and prepared by laser cutting, laser drilling, screen printing, and high-temperature sintering, which was made of alumina ceramic sensitive element. The high-temperature test platform was built to test the sensor. The test results showed that the sensitivity of the sensor is 106.67 kHz/°C in the low-temperature range of 25 °C–400 °C, and the sensitivity is 437.5 kHz/°C in the high-temperature range of 400 °C–1200 °C, indicating that the sensitivity of the sensor in the high-temperature range is much higher than that in the low-temperature range. The morphology of platinum film on the surface of the sensor at different stages was characterized by scanning electron microscopy (SEM), which can explain that long-time high-temperature use is the main reason for sensor failure.