Millimeter-Wave Double-Ridge Waveguide and Components

A 45-110-GHz double-ridge waveguide, denoted by WRD45110, is designed, fabricated, and tested. A detailed parametric study is carried out to develop a cross section with in-band attenuation for the straight line below 0.06 dB/cm and group delay below 0.06 ns/cm. Ridges are rounded so that the theoretical peak power handling is above 400 W. For practical characterization, various straight lines are built with the direct metal laser sintering (DMLS) 3-D printing process in aluminum and stainless steel. Precision, repeatability, mechanical strength, and electrical performance are then evaluated. A 90° twist, a 90° E-bend, a 90° H-bend, and an open termination load are also developed, 3-D printed, and measured. Good performance of all lines and components and ability to cascade functional pieces are demonstrated.