Design of a novel planar LHM with broadband and double negative medium

We design the unit cell of the planar LHM which has broad bandwidth. The relative bandwidth of the LHM proposed in here is 36.5%, and the slab filled with a FR4 dielectric substrate. Then the geometry of the unit cell is not only cheaper fabrication but also lower loss. Moreover, the central frequency of the LHM can be tuned through changing the CSRR period along Z direction while keeping the relative bandwidth. The DNG property is shown by the simultaneously negative effective permittivity and effective permeability extracted from the transmission and reflection data of LHM slab, and it is confirmed by the equivalent method which is described in detail in this paper.