Multi-band cylindrical antenna using ε-near-zero gap launchers

The ε-near-zero (ENZ) tunneling phenomenon has been shown to allow full transmission of waves through narrow channels, even in the presence of a strong geometric mismatch. Here we propose an application of this principle to realistic 3D cylindrical antenna geometries, with the purpose of realizing a frequency-hopping multi-band radiator working in a 5:1 bandwidth in the millimetre-wave regime, of interest for a variety of real-life antenna applications.