Substrate free G-band Vivaldi antenna array design, fabrication and testing

The antenna pattern of a linear Vivaldi antenna array fabricated for G-band (140-220 GHz) radar applications was measured to explore the performance of a novel fabrication technique that allows for miniature waveguide to 3D AirCoax transitions and small footprint millimeter wave RF networks without the need of a substrate. The array includes four Vivaldi elements fed through a 4:1 equal split power divider and two dummy elements at both edges. The array pitch is configured at lambda/2 (about 750 microns). The design allows for scaling into a 2D array for beam steering applications using miniature phase shifters, which are currently being developed. The fabrication technique, as well as measured beam patterns, are presented and opportunities as well as challenges are discussed.