Higher Order Modes Propagation in Rectangular Waveguides Made from Anisotropic Material

Using Carbon Fiber Reinforced Polymer (CFRP) materials for high frequency structures introduces high amount of loss due to the limited anisotropic conductivity. This loss is critical for structures like waveguides which are normally used for high power transmissions. In this paper we analyze the loss mechanism in a rectangular waveguide made from anisotropic material. We show that mode conversion is the dominant loss mechanism factor in a waveguide made from anisotropic material and can be avoided by using the waveguide for higher order modes. Insertion loss of a WR-90 waveguide with anisotropic walls has been simulated for different propagation modes and it has been shown that the insertion loss is more than 26 dB lower when the waveguide is used for TM
₂₂
mode rather than TE
₁₀
.