Toroidal Metasurface for High Efficiency Sensing

A novel toroidal metasurface insensitive to incident angles is presented which is able to provide a platform for high efficiency sensing at microwave frequency range. The simulated and measured results show that the radiation power of toroidal response is dominant and almost, the almost total energy is transmitted from metasurface around resonant frequency. In addition, we experimentally demonstrate that the toroidal metasurface is very sensitive to the structure configuration and has a high sensitivity of 0.78 GHz/RIU to detect the permittivity of surrounding materials, which has the potential applications in refraction index sensing and bio-sensing.