A 3-D Isotropic Left-Handed Metamaterial Based on the Rotated Transmission-Line Matrix (TLM) Scheme

A 3-D isotropic left-handed metamaterial based on the rotated transmission-line matrix (TLM) scheme is presented in this contribution. First, the discrete electrodynamics theory of the rotated TLM scheme is briefly revisited. The corresponding 3-D metamaterial is analyzed in terms of its dispersion relation, Bloch impedance, principal axes propagation, differential/common mode excitation, and composite right/left-handed response. A practical realization of this 3-D metamaterial, based on metal-insulator-metal capacitors and thin wires, is proposed and experimentally demonstrated. A simplified planarized implementation, preserving the same network topology, is then proposed with two alternative configurations. Parasitic effects resulting from planarization are analyzed and design guidelines are given to mitigate them. Finally, this structure is demonstrated by a full-wave simulation to exhibit the expected 3-D-isotropic left-handed behavior.