Planar Metamaterial Microwave Sensors for Characterization of Dielectric Materials

Abstract

Metamaterials can be integrated into planar microwave sensors for field localization and enhancement as well as sensitivity improvement in permittivity-based sensing measurements. This chapter reviews metamaterial-based planar microwave sensors for characterizing dielectric materials. It begins by introducing planar microwave sensors. The subsequent section focuses on the sensing principles of planar microwave sensors loaded with metamaterial-inspired resonators, namely frequency shift, frequency splitting, and amplitude or phase variation. Furthermore, recent advances in metamaterial-integrated sensors are discussed, focusing on the types of samples under test, including solid samples in bulk and powder form, and liquid samples in fluid tubes or microfluidic channels. Furthermore, planar antennas loaded with metamaterial elements are also explored. To enhance understanding of frequency-variation sensors, a microstrip transmission line loaded with complementary split ring resonators is simulated. Finally, the design strategies of planar metamaterial-based sensors are reviewed.