Wide angle terahertz sensing with a cross-dipole frequency selective surface

In this work, a terahertz sensor based on a cross dipole frequency selective surface is analyzed and experimentally tested. The sensing structure is optimized for operation at the fundamental bandstop resonance near 0.7 THz and characterized under normal and oblique incidence. The sensing performance as a function of the incidence angle and the wave polarization is evaluated with good agreement between simulations and measurements. It is shown that a figure of merit for the proposed sensor can be enhanced from 0.2 up to 0.6 due to switching from normal to oblique excitation, which yields the maximum performance for TM polarization at the incidence angle of 70 degrees. The presented results demonstrate a wide angle operation regime in THz sensing that opens up an alternative approach in improving capabilities of sensing devices. (C) 2016 AIP Publishing LLC.