Loss and dispersion characteristics of dielectric-coated metallic hollow waveguides are simulated for frequencies ranging from 140 GHz to 220 GHz. Results show that the dielectric layer coating cannot reduce the transmission loss in this frequency band when the operation wavelength is close to the inner diameter of the waveguide. However, the electric field profile of the model is distorted because the dielectric layer and dispersion of the waveguide switches from positive to negative. The dispersion variation and zero-dispersion position in dielectric-coated metallic hollow waveguides with different dielectric layer thicknesses are analyzed and summarized. Dispersion compensation methods and schemes for metal waveguides are proposed using waveguides with different dielectric layer thicknesses. The result shows that zero-dispersion can be achieved at different frequencies and flat and low dispersion over specific frequency bands can be realized. It guides structural design and fabrication parameter control for the waveguides used in this frequency band.