SiGe BiCMOS D-Band Heterodyne Power Mixer With Back-Off Efficiency Enhanced by Current Clamping

A D-band power upconverter in a 55-nm SiGe BiCMOS is presented. The low-output resistance of a switching quad is identified as a limiting factor to mixer power generation in D-band, and common-base transistors are stacked for output power enhancement. Moreover, the current clamping mechanism is exploited to scale the average supply current with output power, improving the efficiency in back-off. Experimental results demonstrate $ {P_{\mathrm{ sat}}}\,\,{=}$ 6.3 dBm and ${oP_{\mathrm{ 1dB}}}\,\,{=}$ 4.5 dBm at 140 GHz, with efficiency of 3.05% and 2.47%, respectively. The power consumption, from a 2-V supply, rises from 70 mW at the quiescent point to 140 mW at $ {P_{\mathrm{ sat}}}$ . The measured output power and efficiency compare favorably against previous works.