Modified sensors open the door to temperature-sensing applications

The temperature sensor market is expected to grow significantly within the next few years because of the increasing awareness of climate change and the need for monitoring systems for renewable energy. High-precision and low-cost temperature sensors will be essential in meeting this demand.

The low profile and compact size of planar sensors — a type of microwave sensor — are ideal for use in lab-on-a-chip technology. Planar sensors are typically used to find the dielectric characteristics of solids and liquids, not to monitor temperature changes.

Wang et al. investigated the use of a planar resonator system integrated with a temperature-sensitive substrate to monitor ambient temperature. The team designed a high-performance substrate synthesized with titanium dioxide and zinc oxide and configured it into a complementary split-ring resonator.

“As the temperature changes, the characteristics of the substrate material are modified, and a shift in the sensor’s resonance frequency appears,” said author Mingkun Du. “The ambient temperature can be determined by observing the frequency variation.”

A synergistic improvement in sensor performance resulted from the structural design change and material modification. The researchers analyzed the substrate material with X-ray diffraction, scanning electron microscopy, Raman spectra, and X-ray photoelectron spectroscopy. They validated the fabricated planar resonator sensor in the temperature range of −50⁰C to 90⁰C using a vector network analyzer and a high-low temperature chamber.

“The sensors prepared by these novel materials can be used in devices for aeroengines, transformer monitoring systems, health and safety systems, wireless temperature sensing, and in harsh environments with ultra-high temperatures,” said author Lingxia Li.

Source: “An UHF band planar resonator temperature sensor constructed from high-performance titanium dioxide system microwave dielectric ceramics: Towards integrated ceramic-based sensor devices,” by Yaoxing Wang, Mingkun Du, and Lingxia Li, Applied Physics Reviews (2024). This article can be accessed at https://doi.org/10.1063/5.0218434 .