Low loss broadband polarization independent fishnet negative index metamaterial at 40 GHz

We present a polarization independent fishnet negative index metamaterial at 40 GHz. The structure is investigated theoretically using finite element method simulations and experimentally by measuring the amplitude and phase of the S-parameters. The experimental setup for free space measurements of both transmission and reflection is hereby introduced. The internal properties are thereafter retrieved and show the double-negative behavior of the structure. This negative index metamaterial exhibits very high transmission (−0.13 dB), low reflection (−33.1 dB) and a high figure of merit (FOM = |Re(n)/Im(n)| = 42), where the real part of the refractive index is nearly −1 (Re(n) = −0.93) at 40 GHz.

► We propose a novel negative index metamaterial fishnet design at 40 GHz. ► The design is polarization independent. ► It exhibits high transmission, low loss and broad negative index frequency range. ► Simulation and experimental results are in good agreement.