Metamaterial-Based Antennas and a Metasurface-Based Terahertz Frequency Splitter

This chapter discusses four metamaterial-based antennas and one metasurface-based splitter. It is found that a metamaterial-based double-line antenna radiates a linearly polarized broadside beam across a wide frequency range, and a metamaterial-based open loop antenna radiates a dual-band counter circularly polarized wave. It is also found that a metamaterial-based two-arm spiral antenna shows different maximum gains during its dual-band operation. Similar behavior is revealed in a single-arm metamaterial-based curl antenna. An efficient implicit finite-difference time-domain method formulated in cylindrical coordinates and based on a locally one-dimensional scheme is devised to analyze the performance of a metasurface-based terahertz frequency splitter. The frequency splitting behavior at 1.0 and 1.5 THz is demonstrated with a radially polarized wave as an incident wave. The computation time for the analysis is reduced to approximately one-half of that for the explicit Finite-Difference Time-Domain (FDTD) method, while maintaining comparable accuracy.