A 70–170-GHz InP Differential Non-Uniform Distributed Amplifier Using Tapered Output Coupled Line for High Output Power

This paper presents a 70–170 GHz differential non-uniform distributed amplifier (NDA) with 20.9 dBm peak output power and 14.7 dB peak gain. A new wideband low-loss tapered output coupled line enables a wide characteristic impedance range to increase the NDA’s output power while maintaining a bandwidth covering W- and D-band. Moreover, the NDA’s low termination and load impedances boost the high-frequency forward currents propagating to the output, where a 1:1 balun effectively combines differential signals, rejects even harmonics, performs impedance transformation, and integrates DC biasing networks. The proposed techniques yield high output power, broadband gain, and a high 2nd harmonic rejection ratio (HRR) for the differential NDA. The prototype exhibits a peak gain of 14.7 dB over a 3-dB bandwidth of 80–160 GHz and maintains >10 dB gain over 70–170 GHz. The saturated power is >17.5 dBm, 3rd HRR is >27 dBc, and 2nd HRR is >40 dBc.