Share Email Print
cover

Proceedings Paper

Gas spectroscopy system with 245 GHz transmitter and receiver in SiGe BiCMOS
Author(s): Klaus Schmalz; Nick Rothbart; Johannes Borngräber; Selahattin Berk Yilmaz; Dietmar Kissinger; Heinz-Wilhelm Hübers
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

The implementation of an integrated mm-wave transmitter (TX) and receiver (RX) in SiGe BiCMOS or CMOS technology offers a path towards a compact and low-cost system for gas spectroscopy. Previously, we have demonstrated TXs and RXs for spectroscopy at 238 -252 GHz and 495 - 497 GHz using external phase-locked loops (PLLs) with signal generators for the reference frequency ramps. Here, we present a more compact system by using two external fractional-N PLLs allowing frequency ramps for the TX and RX, and for TX with superimposed frequency shift keying (FSK) or reference frequency modulation realized by a direct digital synthesizer (DDS) or an arbitrary waveform generator. The 1.9 m folded gas absorption cell, the vacuum pumps, as well as the TX and RX are placed on a portable breadboard with dimensions of 75 cm x 45 cm. The system performance is evaluated by high-resolution absorption spectra of gaseous methanol at 13 Pa for 241 - 242 GHz. The 2f (second harmonic) content of the absorption spectrum of the methanol was obtained by detecting the IF power of RX using a diode power sensor connected to a lock-in amplifier. The reference frequency modulation reveals a higher SNR (signal-noise-ratio) of 98 within 32 s acquisition compared to 66 for FSK. The setup allows for jumping to preselected frequency regions according to the spectral signature thus reducing the acquisition time by up to one order of magnitude.

Paper Details

Date Published: 24 February 2017
PDF: 8 pages
Proc. SPIE 10103, Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications X, 101031L (24 February 2017); doi: 10.1117/12.2250030
Show Author Affiliations
Klaus Schmalz, IHP (Germany)
Nick Rothbart, Deutsches Zentrum für Luft- und Raumfahrt e.V. (Germany)
Humboldt-Univ. zu Berlin (Germany)
Johannes Borngräber, IHP (Germany)
Selahattin Berk Yilmaz, Silicon Radar (Germany)
Dietmar Kissinger, IHP (Germany)
Technische Univ. Berlin (Germany)
Heinz-Wilhelm Hübers, Deutsches Zentrum für Luft- und Raumfahrt e.V. (Germany)
Humboldt-Univ. zu Berlin (Germany)


Published in SPIE Proceedings Vol. 10103:
Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications X
Laurence P. Sadwick; Tianxin Yang, Editor(s)

© SPIE. Terms of Use
Back to Top