A 60 GHz branch line coupler fabricated using integrated rectangular coaxial lines

A 60 GHz branch line coupler is fabricated using rectangular coaxial transmission lines. The coupler was built using a new microfabrication process. To the authors' knowledge, this is the first V-Band demonstration of devices fabricated in this manner. The coupler has a measured insertion loss of 3.4-4.1 dB over the 57-63 GHz frequency range. The device was fabricated successfully in a single design pass. A comparison between the design simulations and the measured results are presented.