Millimeter waveguide fabrication to reduce transmission loss by diffusion bonding, light-curing resin or dielectric partially-filling

We have discussed the three types of millimeter waveguides for redusing the transmission loss. The diffusion-bonding hollow-waveguide array of copper achieves 60% antenna efficiency for 31.4dBi gain at 93.7GHz. The hollow wavequide of laser-curing resin with copper electroplating with 25mm lenght achieves −01.dB transmission at 94GHz. The dielectric half-filled parallel plate waveguide is expected to reduce the transmission loss by about 40% in 60GHz band.