Dear there,
I'm wondering if it's always true that metal material has lower loss than dielectric material at THz frequencies. in other words, dielectric loss is higher than metal loss at higher frequencies.
Please provide me with some references or formulas to discuss.
Thanks in advance
Hai BQ
There are several dielectric materials that can be used at THz frequencies. Some examples include barium titanate, gallium arsenide (GaAs), zinc oxide (ZnO), and silicon carbide (SiC). These materials all have different properties, so it's important to do research to determine which material would best suit your application.
Dear Sagayaraj
thanks for your reply.
however, I'm still looking for that is metal material is the best one in terms of losses at THz band, or do these words look like a Bold sentence?
It is generally true that metal materials have lower loss than dielectric materials at terahertz (THz) frequencies. This is because the loss in metal materials is dominated by the skin effect, which causes the current to flow in a thin layer near the surface, reducing the amount of material that contributes to loss. In contrast, dielectric materials have a higher loss due to the absorption of THz radiation by the molecular vibrations of the material.
One way to quantify the loss of a material is by using its complex permittivity, which is defined as the ratio of the electric flux density to the electric field in a material. The real part of the complex permittivity represents the dielectric constant and the imaginary part represents the loss. The loss tangent is the ratio of the imaginary part of the permittivity to the real part.
Metal materials have a negative real part of the permittivity and a very small imaginary part at THz frequencies which results in a small loss tangent. On the other hand, dielectric materials have a positive real part of the permittivity and a larger imaginary part which results in a larger loss tangent.
It is worth noting that the loss of a material is also dependent on the frequency, the temperature, and the pressure. Some references that discuss this topic are "Terahertz spectroscopy of dielectrics" by S.A. Myslivets, "Dielectric properties of metals and semiconductors" by M.S. Shur and "Introduction to terahertz science and technology" by Y. Tanaka.
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