Journal article
Molecular Spectroscopy With a Compact 557-GHz Heterodyne Receiver
German Aerospace Center1
Chalmers University of Technology2
Omnisys Instruments AB3
Fraunhofer-Gesellschaft4
Department of Electrical Engineering, Technical University of Denmark5
Electromagnetic Systems, Department of Electrical Engineering, Technical University of Denmark6
Wasa Millimeter Wave AB7
Ferdinand Braun Insitute8
We report on a heterodyne terahertz spectrometer based on a fully integrated 557-GHz receiver and a digital fast Fourier transform spectrometer. The receiver consists of a chain of multipliers and power amplifiers, followed by a heterostructure barrier varactor tripler that subharmonically pumps a membrane GaAs Schottky diode mixer.
All sub-components are newly developed and optimized with regard to the overall receiver performance such as noise temperature, power consumption, weight and physical size. The receiver works at room temperature, has a double sideband noise temperature as low as 2000 K at a maximum power consumption of 4.5 W with an Allan time of 10 s and a sideband gain ratio of 0.52.
The performance of the spectrometer is demonstrated by absorption spectroscopy of H2O and CH3OH with an instantaneous bandwidth of 1.5 GHz and a resolution of 183 kHz. Several pressure broadening parameters of methanol absorption lines were determined, that agree with other published data. Using the experimentally determined molecular parameters the CH3OH absorption spectrum could be modeled with very high precision.
| Language: | English |
|---|---|
| Publisher: | IEEE |
| Year: | 2014 |
| Pages: | 469-478 |
| ISSN: | 21563446 and 2156342x |
| Types: | Journal article |
| DOI: | 10.1109/TTHZ.2014.2326554 |
| ORCIDs: | Johansen, Tom Keinicke |
CH3OH MMICs Mixers Schottky diode heterostructure barrier varactors mHEMT methanol molecular spectroscopy power amplifiers terahertz
<formula formulatype="inline"> <tex Notation="TeX">${\hbox{CH}}_{3}{\hbox{OH}}$</tex></formula> Absorption Allan time Amplitude modulation CH<sub>3</sub>OH Fourier transform spectrometers GaAs H<sub>2</sub>O II-VI semiconductors Noise Receivers Schottky diode mixer Schottky diode mixers Spectroscopy Temperature measurement absorption spectroscopy absorption spectrum bandwidth 1.5 GHz compact heterodyne receiver digital fast Fourier transform spectrometer fast Fourier transforms frequency 183 kHz frequency 557 GHz gallium arsenide heterodyne receiver heterodyne terahertz spectrometer heterostructure barrier varactor tripler methanol absorption lines microwave measurement microwave receivers organic compounds power 4.5 W power amplifier sideband gain ratio terahertz spectroscopy time 10 s varactors
