| Since the first experimental demonstration of the negative-refractive-index metamaterial by Shelby et al. in the early 2000s, metamaterials have experienced great interest from research community, resulting in an increasingly large number of publications. Truly three-dimensional (3D) metamaterials, which are able to interact with electromagnetic sources from free space, have been targeted in much of metamaterial research. The physical implementation of such structures is often exorbitantly complicated. In some applications, which require free-space sources to be particularly polarized, 3D metamaterials can be replaced by volumetric metamaterials, which are an extension of 2D metamaterials in the third dimension, and are realized by stacking layers of 2D metamaterials. Volumetric metamaterials employ both surface-mount and fully-printed elements as reactive loads. Fully printed volumetric metamaterials are the most cost-effective because their fabrication is suitable for standard lithography processes. However, previous fully-printed structures suffered from weak reactive loads, resulting in a high operation frequency, hence, a large electrical length per unit cell. This thesis presents a bi-planar design utilizing MIM-type capacitors and dual-arm spiral inductors, which can easily be fabricated with normal printed-circuit-board technology, making it low-cost. The proposed structure operates at 4.4 GHz, resulting in a small electrical length of one eleventh of free-space wavelength. The simulated data show that the structure can be treated as an isotropic effective medium possessing effective permittivity, permeability, and refractive index close to negative unity. The metamaterial may find applications as flat lenses in microwave hyperthermia, and in the improvement of antenna performance. |
