Focusing of a Flat Left-Handed Metamaterial Lens in a Heterogeneous and Lossy Medium

For applications such as near-field target detection and tumor hyperthermia with a flat left-handed metamaterial (LHM) lens, a microwave will be focused in the heterogeneous and lossy medium. Different from the focusing of a flat LHM lens in vacuum as reported in most previous studies, the medium loss and heterogeneity will affect the focusing performance of the LHM lens. Numerical simulations indicate that the medium loss will degrade the focusing resolution, while the heterogeneity of random variability within ±30% will affect the focusing resolution to a limited extent. Both the loss and heterogeneity of the medium will shift the focal point away from the image plane. When focusing in a medium with different permittivity values, an LHM lens will also have different focusing resolutions due to different electric thicknesses.