Engineering Approach to Modelling Frequency Dispersion Within Normal Metals at Room Temperature for THZ Applications

Abstract

Abstract-When compared to the over-simplified classical skin-effect model, the accurate classical relaxation-effect modelling approach for THz structures at room temperature can be mathematically cumbersome and not insightful. This paper introduces various interrelated electrical engineering concepts as tools for characterizing the intrinsic frequency dispersive nature of normal metals at room temperature. This engineering approach dramatically simplifies the otherwise complex analysis and allows for a much deeper insight to be gained into the classical relaxation-effect model. For example, it explains how wavelength can increase proportionally with frequency at higher terahertz frequencies. This is the first time that such an approach has been developed for the modelling of intrinsic frequency dispersion within a metal.While the focus has been on the characterization of normal metals (magnetic and non-magnetic) at room temperature, it is believed that the same methodology may be applied to metals operating in anomalous frequency-temperature regions, superconductors, semiconductors, carbon nanotubes and metamaterials.

Propagation Characteristics of Rectangular Waveguides at Terahertz Frequencies with Finite-Difference Frequency-Domain Method

“…Using an approximation, the metal could be treated like a free electron gas. When the frequency increases to the THz range, the frequency dispersion of the conductivity can be accurately described with the so-called Drude dispersion model [4] as:…”

“…At present there are many modeling methods available to characterize the transmission losses of hollow rectangular waveguides operating in the THz frequency range, which include the analytical perturbation method and numerical techniques [2,3]. However, the frequency dispersion of the finite conductivity at THz frequencies is often ignored in modeling metallic waveguides with these methods [4,5], which may result in drastic errors for the transmission losses. When considering the dispersion effect of conductivity with commercial EM solvers (e.g., Ansoft HFSS TM , CST Microwave Studio, etc.…”

“…In this paper, a hollow rectangular metallic waveguide and one with interior dielectric coatings have been analyzed at THz frequencies. The Drude dispersion model was employed for accurate modeling of the metal conductivity at THz frequencies [3,4,5]. By solving the Eigen equations consisting of six field components, the phase constant and attenuation constant can be found for a given frequency.…”

Improved ‘THz Torch’ technology for short-range wireless data transfer

“…With the latter, there is real motivation for finding ubiquitous applications to commercially exploit the 'THz gap'. To do this, improvements in our analytical [1][2] and numerical CAD [3] modelling techniques must be found, as well as in designing metal-pipe substrate integrated waveguides (SIWs) [4][5][6], antennas [7], terahertz multi-chip modules (T-MCMs) [8] and demonstrating new applications [9,10].…”