Fabrication of waveguide butler matrix for short millimeter-wave using X-ray lithography

The microfabrication technique based on X-ray lithography has recently been applied to construct PTFE-based microstructures. This paper attempts to fabricate an integrated waveguide Butler matrix for short millimeter-wave using X-ray lithography. First, a cruciform 3-dB directional coupler and an intersection circuit are designed at 180 GHz. Then, a 4×4 butler matrix with horn antennas is designed and fabricated. Finally, the measured radiation patterns of the Butler matrix are shown.