189-GHz-Bandwidth InP-HBT Baseband Amplifier Module With 0.5-mm Coaxial Connectors

This paper presents a 189-GHz-bandwidth InP-HBT-based baseband amplifier module employing 0.5-mm coaxial connectors. The amplifier IC, fabricated in a 250-nm InP-HBT technology, achieves a 3-dB bandwidth of 200 GHz with 7.2-dB gain peaking up to 160 GHz to compensate for assembly losses. The IC is flip-chip mounted on a printed circuit board using gold stud bumps to minimize parasitic effects. The module integrates DC-blocking functions at both input and output ports. The fabricated module demonstrates a 3-dB bandwidth of 189 GHz, with output 1-dB compression points of 4.1 dBm at 120 GHz and 3.0 dBm at 140 GHz. Wideband linear amplification is validated through time-domain measurements using a 224-GBd PAM-4 (448-Gb/s) signal. To the best of our knowledge, this work demonstrates the widest reported bandwidth for a baseband amplifier module and the first active module employing 0.5-mm coaxial connectors.