Zoned fishnet metamaterial lens with millimetre-wave dual-band response

Here we present numerical and experimental results of a zoned fishnet metamaterial lens with dual-band response. Good performance is demonstrated at frequencies 54 GHz and 55.5 GHz at which the fishnet metamaterial behaves as a medium with refractive indexes n
₁
= -0.78 and n
₂
= -0.43, respectively. Experimental focal lengths are FL
₁
=8.4λ
₁
and FL
₂
=9.4λ
₂
. The dual-band response of zoned fishnet metamaterial lens shows potential for application in non-mechanical zoom millimeter-wave imaging system.