University of Oulu

S. P. Singh, T. Rahkonen, M. E. Leinonen and A. Parssinen, "Design Aspects of Single-Ended and Differential SiGe Low-Noise Amplifiers Operating Above fmax/2in Sub-THz/THz Frequencies," in IEEE Journal of Solid-State Circuits, vol. 58, no. 9, pp. 2478-2488, Sept. 2023, doi: 10.1109/JSSC.2023.3264475.

Design aspects of single-ended and differential SiGe low-noise amplifiers operating above fmax/2 in Sub-THz/THz frequencies

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Author: Singh, Sumit Pratap1; Rahkonen, Timo2; Leinonen, Marko E.1;
Organizations: 1Center for Wireless Communications, University of Oulu, 90570 Oulu, Finland
2Circuits and Systems Research Unit, University of Oulu, 90570 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2023
Publish Date: 2023-11-06


This article presents a single-stage single-ended (SE) and a multistage pseudo-differential cascode low-noise amplifiers (D-LNA) with their center frequencies at 235 and 290 GHz, respectively. Both low-noise amplifiers (LNAs) are designed beyond half of the maximum frequency of oscillation (\(f_{\text {max}}\)) in 130-nm SiGe BiCMOS technology with \(f_{t}/f_{\text {max}}\) of 300 / 450 GHz. Implications of gain-boosting and noise reduction techniques in cascode structure are analyzed and it is observed that beyond \(f_{\text {max}}/2\), these techniques do not provide desired benefits. The single-stage SE LNA is designed to ascertain the theoretical analysis, and the same analysis is further implemented in staggered tuned four-stage LNA. Single-stage SE LNA provides a small signal gain of 7.8 dB at 235 GHz with 50 GHz of 3-dB bandwidth by consuming 18 mW of power. Four-stage differential LNA gives 12.9 dB of gain at center frequency 290 GHz and 11.2 dB at 300 GHz by drawing 68 mA current from the 2-V supply. The 3-dB bandwidth of differential LNA is measured to be 23 GHz. Noise figure measurements of both LNAs are performed using a gain-method technique with their measured noise figure values of 11 and 16 dB, respectively. This work successfully demonstrates the possibility of using a Si-based process to implement amplifiers beyond \(f_{\text {max}}/2\). To the authors’ best knowledge, the four-stage differential LNA achieves, without any gain-boosting technique, the highest gain at \(2/3(f_{\text {max}})\) with decent noise figure performance in SiGe technology.

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Series: IEEE journal of solid-state circuits
ISSN: 0018-9200
ISSN-E: 1558-173X
ISSN-L: 0018-9200
Volume: 58
Issue: 9
Pages: 2478 - 2488
DOI: 10.1109/JSSC.2023.3264475
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: This work was supported by the Academy of Finland through the 6G Flagship program under Grant 346208.
Academy of Finland Grant Number: 346208
Detailed Information: 346208 (Academy of Finland Funding decision)
Copyright information: © The Author(s) 2023. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see