This paper describes the design of a 140-GHz low-noise amplifier in 130-nm SiGe BiCMOS technology. The circuit is aimed for a high integration-density imaging radiometer, where several receivers are integrated on the same die. Thus, we particularly focus on minimizing the die area and power consumption. The two-stage amplifier is composed of cascode stages with gain boosting base resonators. The performance of a single cascode stage is optimized by correctly sizing the base resonator to avoid instability. The circuit features gain of 19 dB at 140 GHz, and noise figure of 7 dB, while consuming only 15 mW and occupying a die area of 0.1 mm².