Advanced Materials for RF Sensors in Harsh Environments: A Comprehensive Review

The need for highly efficient low-power emission systems has increased drastically due to technological enhancements. To achieve maximum efficiency and throughput, systems need to be operated in harsh conditions, such as high temperature, high pressure, electromagnetic interference, high radiation, and chemically corrosive environments. Systems functioning in these environments must be continuously monitored to avoid structural and functional breakdowns caused by these extreme environmental conditions. Traditional wired sensors cannot be used since they need physical contact or a power supply through battery and, thus, cannot withstand severe operating conditions. These scenarios demand a wireless means of sensing. Conventional silicon (Si)-based sensors have performance limitations above 150 °C, which has prompted researchers to investigate novel materials for designing wireless sensors that can operate in such environments. This article provides a comprehensive review of the materials, which can be used to design wireless radio frequency sensors in harsh environmental conditions. The physical, electrical, thermal, and mechanical properties of these materials and their polytypes were studied, and based on them, comparisons have been drawn. The applications of each material and available techniques to design different types of sensors, such as temperature, pressure, and gas, are also presented.