A 300-GHz Upconverter With 0-dBm P_sat and 44-GHz Bandwidth in 130-nm SiGe BiCMOS

A 300-GHz modified Gilbert upconverter with highoutput power and wide bandwidth (BW) in a 130-nm SiGe BiCMOS process is presented. A low-impedance transmission line (low-Z(0 )TL) is introduced to achieve impedance matchingbetween the mixer core and the RF/LO balun. This low-loss low-Z(0 )TL eliminates the need for lossy capacitors to groundat subterahertz frequency, thereby improving the output power and BW. The impedance transformation using the balun and low-Z(0 )TL is analyzed to achieve optimum impedance matching.A high-powerx6 frequency multiplier chain (x6 FMC) with a P(sat )of 8-9 dBm at 230-250 GHz is utilized to provide the LO source for the upconverter, further enhancing the output power.The proposed upconverter achieves a measured peak saturated output power (P-sat) of 0 dBm at 280 GHz with a maximum 3-dB BW of 44 GHz. The measured peak 1-dB output power of-3.6 dBm and conversion gain (CG) of-8.4 dB are obtained at 290 and 280 GHz, respectively. Moreover, to the best of our knowledge, the proposed upconverter exhibits the highest output power in silicon-based processes beyond 270 GHz.