Single-Layer, All Metallic Metasurface Filter With Nearly 90° Angularly
We present a method to design a single-layer angular stable metasurface
(ASM) filter unit cell for a nearly full range of angles of incidence.
We formulate the optimization criterion using the energy balance
condition derived from Poynting’s Theorem. The proposed unit cell has a
“cloverleaf” geometry, and we show that by adjusting the properties of
the cloverleaf we obtain an angularly stable resonance which extends to
nearly 90 degree incidence. After optimization, we revisit the energy
and show using a dispersive impedance model how optimization at three
points is enough to obtain the required balance for the entire angular
spectrum. The proposed ASM was fabricated from a bare aluminum sheet and
measured for both TE and TM polarization, with angularly stable
performance that matches the theory and simulation. The proposed design
offers new capabilities for radar and antenna design applications.