An Air-Filled Double-Sided Gap Waveguide Based on Glass Packaging for mm-W Applications

This letter, for the first time, implements an air-filled glass-based double-sided gap waveguide (Glass-DS-GWG) using micropatterned adhesive bonding. This advanced bonding solves the challenge of uncertain gap height in conventional GWG-based devices. Meanwhile, the high-efficiency laser-induced wet etching (LIWE) removes most of the transmission medium. Extremely low-loss transmission and stable performance are obtained. Multiple $V$ -band transmission lines are fabricated in a 6-in glass wafer for demonstration. As the measured results, the transmission loss of 0.018–0.03 dB/mm, the average bend leakage of only 0.055 dB, and the isolation of better than 25 dB are achieved. Therefore, the proposed Glass-DS-GWG solution with the advantages of low loss, low cost, low profile, and high integration suits the fabrication and integration of radio frequency (RF) devices for millimeter-wave (mm-W) applications.