Wideband and fast THz spectrometer using dual-frequency-comb on CMOS
Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2018
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| Online Access: | http://hdl.handle.net/1721.1/118025 |
| _version_ | 1826217767620050944 |
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| author | Wang, Cheng |
| author2 | Ruonan Han. |
| author_facet | Ruonan Han. Wang, Cheng |
| author_sort | Wang, Cheng |
| collection | MIT |
| description | Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018. |
| first_indexed | 2024-09-23T17:08:50Z |
| format | Thesis |
| id | mit-1721.1/118025 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T17:08:50Z |
| publishDate | 2018 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/1180252019-04-12T21:53:01Z Wideband and fast THz spectrometer using dual-frequency-comb on CMOS Wideband and fast Terahertz spectrometer using dual-frequency-comb on Complementary metal-oxide-semiconductor Wang, Cheng Ruonan Han. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science. Electrical Engineering and Computer Science. Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018. Cataloged from PDF version of thesis. Includes bibliographical references (pages 71-75). Millimeter-wave/terahertz rotational spectroscopy of polar gaseous molecules provides a powerful tool for complicated gas mixture analysis. Here, a 220-to-320 GHz dual-frequency-comb spectrometer in 65-nm bulk CMOS is presented, along with a systematic analysis on fundamental issues of rotational spectrometer, including the impacts of various noise mechanisms, gas cell, molecular properties, detection sensitivity, etc. The spectrometer utilizes two counter-propagating frequency-comb signals to seamlessly scan the broadband spectrum. The comb signal, with 10 equally-spaced frequency tones, is generated and detected by a chain of inter-locked transceivers on chip. Each transceiver is based on a multi-functional electromagnetic structure, which serves as frequency doubler, sub-harmonic mixer and on-chip radiator simultaneously. In particular, theory and design methodology of a dual transmission line feedback scheme are presented, which maximizes the transistor gain near its cut-off frequency fmax. The dual-frequency-comb scheme does not only improve the scanning speed by 20 x, but also reduces the overall energy consumption to 90 mJ/point with 1 Hz bandwidth (or 0.5 s integration time). With its channelized 100-GHz scanning range and sub-kHz specificity, wide range of molecules can be detected. In the measurements, state-of-the-art total radiated power of 5.2 mW and single sideband noise figure (NF) of 14.6~19.5 dB are achieved, which further boost the scanning speed and sensitivity. Lastly, spectroscopic measurements for carbonyl sulfide (OCS) and acetonitrile (CH3CN) are presented. With a path length of 70 cm and 1 Hz bandwidth, the measured minimum detectable absorption coefficient reaches [alpha] gas,min=7 .2 x 10-7 cm- 1 . For OCS, that enables a minimum detectable concentration of 11 ppm. The predicted sensitivity for some other molecules reaches ppm level (e.g. 3 ppm for hydrogen cyanide (HCN)), or 10 ppt level if gas pre-concentration with a typical gain of 10 5 is used. by Cheng Wang. S.M. 2018-09-17T15:54:19Z 2018-09-17T15:54:19Z 2018 2018 Thesis http://hdl.handle.net/1721.1/118025 1051458564 eng MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 75 pages application/pdf Massachusetts Institute of Technology |
| spellingShingle | Electrical Engineering and Computer Science. Wang, Cheng Wideband and fast THz spectrometer using dual-frequency-comb on CMOS |
| title | Wideband and fast THz spectrometer using dual-frequency-comb on CMOS |
| title_full | Wideband and fast THz spectrometer using dual-frequency-comb on CMOS |
| title_fullStr | Wideband and fast THz spectrometer using dual-frequency-comb on CMOS |
| title_full_unstemmed | Wideband and fast THz spectrometer using dual-frequency-comb on CMOS |
| title_short | Wideband and fast THz spectrometer using dual-frequency-comb on CMOS |
| title_sort | wideband and fast thz spectrometer using dual frequency comb on cmos |
| topic | Electrical Engineering and Computer Science. |
| url | http://hdl.handle.net/1721.1/118025 |
| work_keys_str_mv | AT wangcheng widebandandfastthzspectrometerusingdualfrequencycomboncmos AT wangcheng widebandandfastterahertzspectrometerusingdualfrequencycomboncomplementarymetaloxidesemiconductor |