Inhibiting the TE1-mode diffraction losses in terahertz parallel-plate waveguides using concave plates

Area of Science:

• Physics
• Optics
• Waveguide Technology

Background:

• Terahertz (THz) radiation faces significant challenges in long-range transport due to diffraction losses.
• Parallel-plate waveguides (PPWGs) are a potential solution but are susceptible to these losses, particularly for the lowest order transverse electric (TE1) mode.

Purpose of the Study:

• To investigate methods for inhibiting diffraction losses in THz PPWGs.
• To explore the use of slightly concave plates as a means to enhance THz wave propagation.

Main Methods:

• Numerical simulations were performed to model wave propagation.
• Experimental validation was conducted to verify the simulation results.
• Analysis focused on the TE1 mode within the PPWG structure.

Main Results:

• A specific optimal radius of curvature for the concave plates was identified to effectively suppress diffraction losses.
• The introduction of curvature did not result in any additional group-velocity dispersion.
• The proposed method demonstrated the potential for significantly reducing signal degradation.

Conclusions:

• Slightly concave PPWG plates offer a viable strategy for inhibiting diffraction losses.
• This technique enables the potential for long-range transport of THz radiation using the TE1 mode.
• The findings pave the way for practical THz waveguide applications.