A finite element based eigen-analysis of THz nanoantennas

The establishment of a rigorous full-wave eigenanalysis based on finite element method as numerical tool for the understanding and the revealing the characteristics of Terahertz nano-antennas, constitutes the scope of the current work. A tree-cotree splitting formulation method is incorporated for the suppression of all types of spurious modes. An indicative example of a gold nanodimer structure is studied by evaluating its eigenvalues and eigenvectors. First kind absorbing boundary conditions are adopted for the truncation of the infinite solution domain. To understand this nano-antenna behavior the same structure is analyzed when scaled down to the microwave frequencies. The numerical results obtained for the THz and microwave rigimes are compred between them while the THz ones are against related published results.