“…Split-ring resonators (SRRs) are a class of microwave devices that have contributed significantly to the development of contactless, inexpensive, reusable, and real-time microwave sensors. − SRRs consist of metal traces that support electromagnetic waves with a specific resonant frequency. − Materials can be detected, characterized, and classified by translating their electromagnetic interaction with the microwave signal into changes in the sensor’s electrical parameters, such as resonant amplitude, resonant frequency, and quality factor (Q-factor). ,− Recently, microwave sensors have gained significant attention for sensing frost and ice due to the large difference between the dielectric properties of ice and water. , Planar SRRs integrated with microfluidic channels have also enabled read-time noncontact and nonintrusive detection of microbial growth, blood glucose level, and liquid mixtures at low sample volumes, with applications in microbiology, pharmaceutical, and wastewater treatment facilities . Furthermore, implementation of radio and microwave frequency devices as sensors helps enable their use in the digital world via wireless operation, smart sensing, and Internet of Things (IoT) integration. , …”