A Wideband and Wire-Bonding-Free Packaging Concept for Sub-Terahertz Active Devices

This letter proposes a novel wire-bonding-free packaging concept for sub-terahertz (sub-THz) active devices. The approach utilizes a quartz substrate with metal strips patterned on its bottom surface, termed flip-quartz, to achieve direct and broadband interconnection between the chip and planar transmission line. By eliminating traditional wire-bonding, the design significantly reduces parasitic effects and radiation losses, which are critical at sub-THz frequencies. To demonstrate the feasibility, a D-band (110-170 GHz) power amplifier (PA) module was designed, fabricated, and experimentally tested. The measured results exhibit good agreement with on-wafer measurements. Across the entire D-band, the measured small-signal gain is greater than 19 dB, the saturated output power exceeds 17 dBm, and the calculated average insertion loss remains below 1.2 dB. These results establish the proposed packaging concept as a promising solution for future sub-THz applications.