A Low-Power 136-GHz SiGe Total Power Radiometer With NETD of 0.25 K

This paper presents a low-noise SiGe radiometer at 136 GHz developed in an IBM 90-nm SiGe BiCMOS technology. The radiometer consists of a three-stage cascode low-noise amplifier with a gain of 36 dB, and a differential output square-law detector, all on a single chip. The detector results in responsivity of 11 kV/W and a noise equivalent power (NEP) of 0.6 pW/Hz
^1/2
at D-band frequencies. The radiometer chip consumes 45 mW and results in a minimum NEP of 1.4 fW/Hz
^1/2
with a peak responsivity of 52 MV/W at 136 GHz. The single-chip radiometer is suitable for high-resolution imaging systems having a noise bandwidth > 10 GHz and a low 1/f corner frequency . For an integration time of 3.125 mS (τ = 3.125 mS), the temperature resolution [noise equivalent temperature difference (NETD)] is determined to be 0.25 K using several different independent methods, and is the lowest NETD demonstrated in silicon technologies at D-band frequencies. This state-of-the-art performance is comparable to the best III-V imaging systems and proves that the advanced SiGe technology is a reliable option for imaging and radiometry applications.