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 tapered output coupled line with high cutoff frequency and low insertion loss increases the NDA’s output current and output power while maintaining a bandwidth covering W- and D-band. Furthermore, low termination and load impedances improve the 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 with minor RF degradation. The proposed techniques yield high output power, broadband gain, and high 2nd harmonic rejection ratio (HRR) for the differential NDA. The prototype exhibits 14.7 dB peak gain over a 3-dB bandwidth of 80-160 GHz and maintains >10 dB gain over 70-170 GHz. The measured saturated power is >17.5 dBm, 3rd HRR is >27 dBc, and 2nd HRR is >40 dBc.