Minimizing EHF waveguide losses

To minimize RF power transmission losses at high frequencies, rectangualr waveguide has become the standard transmission medium. At EHF frequencies, rectangular waveguide attenuation rises to unacceptably high levels. To minimize waveguide loss, length is minimized. Where this is not possible, a variety of alternatives exist, each having lower attenuation than standard rectangular waveguide and each with its own advantages and limitations. Square circular (modes TE11 and TE01), oversized rectangular, oversized circular (modes TE11 and TE01), and dielectric waveguides are addressed and categorized according to bendability. By choosing the technology with the lowest attenuation which meets the installation's bendability requirements, the optimum transmission method can be determined. Attenuations are calculated for comparison at 44 GHz, but the discussion is general enough to hold throughout the EHF frequency range.