[Formula Omitted]-Band Total Power Radiometer Performance Optimization in an SiGe HBT Technology

• Published in: IEEE transactions on microwave theory and techniques Vol. 60; no. 3; p. 813
• Main Authors: Dacquay, E, Tomkins, A, Yau, K. H. K, Laskin, E, Chevalier, Pascal, Chantre, A, Sautreuil, B, Voinigescu, S. P
• Format: Journal Article
• Language: English
• Published: New York The Institute of Electrical and Electronics Engineers, Inc. (IEEE) 01.03.2012
• Subjects: Noise
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2012.2184132

A [Formula Omitted]-band SiGe HBT total power radiometer is reported with a peak responsivity of 28 MV/W, a noise equivalent power (NEP) of 14-18 [Formula Omitted], and a temperature resolution better than 0.35 K for an integration time of 3.125 ms. The [Formula Omitted] noise corner of the radiometer is lower than 200 Hz. Fabricated in a developmental technology with 270-GHz [Formula Omitted] and 330-GHz [Formula Omitted], it includes a five-stage low-noise amplifier (LNA) with 4-7-GHz bandwidth and over 35 dB of gain centered at 165 GHz, along with a square-law detector with an NEP below 6 [Formula Omitted] up to 170 GHz. An average system noise temperature of 1645 K is obtained using the [Formula Omitted]-factor method and a noise bandwidth of 10 GHz calculated from the measured [Formula Omitted] characteristics of the radiometer. The reduced [Formula Omitted] noise corner frequency in the presence of the amplifier, compared to that of the detector, appears to indicate that, unlike in III-V radiometers, LNA gain fluctuations are not a problem in SiGe HBT radiometers. The circuit consumes 95 mW and occupies [Formula Omitted]. Wafer mapping of the radiometer sensitivity and of the amplifier gain was performed across different process splits. The mapping results demonstrate that the radiometer can be employed as a relatively simple and area-efficient transistor noise-measure monitor, useful in SiGe HBT vertical profile optimization.