An over 110-GHz InP HEMT flip-chip distributed baseband amplifier with inverted microstrip line structure for optical transmission systems

We successfully developed state of the art InP HEMT distributed amplifiers by using inverted microstrip line technology. For one, we achieved a gain of 14.5 dB and a 94-GHz 3-dB bandwidth resulting in a gain-bandwidth product of 500 GHz, and for the other we achieved a gain of 7.5 dB and a 3-dB bandwidth of over 110 GHz. This technology also demonstrates the capability of fabricating ultra-broadband packaged ICs with flip-chip assembly for operation up to the W-band. To our knowledge, these results represent the highest gain bandwidth product and the widest bandwidth for distributed amplifiers reported to date.