This article presents the design and characterization of a real-time frequency-compensated power detector (PD), based on NMOS transistor, integrated in SiGe 55-nm BiCMOS technology from STMicroelectronics, and dedicated to on-chip power detection in the G-band frequencies. An innovative simple circuit (named attenuator) is designed in order to compensate the variation of the voltage sensitivity value with frequency, which is established by exhibiting lower attenuation (smaller real part impedance) at higher frequencies. As a result, the measured sensitivity value is compensated with a small variation (1800 V/W±10%) over the frequency band (140-220) GHz. To the best of the authors' knowledge, this detector is the first design which proposes a real-time frequency compensation at such high- and large-frequency bands. The attenuator was also designed to exhibit an inductive impedance (in the G-band) in order to compensate the capacitive effect of the NMOS, which helps to use smaller NMOS size and, therefore, obtain a higher sensitivity value. Compared to recent works, our detector exhibits a performance belong the current state-of-the-art with a very low noise equivalent power (NEP) value 4.56 pW/ √Hz and a relatively high voltage sensitivity value.