A Millimeter-wave Instrument for Use in a Synergistic, optical/millimeter-wave Approach to Pollution Monitoring
Date
1993-03Author
Bredow, Jonathan W.
Gibbs, D.
Fung, Adrian K.
Tjuatja, Saibun
Giradot, P.
Metadata
Show full item recordAbstract
A multisensor approach is being developed
at the University of Texas at Arlington (UTA) to
improve upon current capabilities in environmental
monitoring. These sensors consist of an FT-IR for
operation in the near to thermal infrared regions of
the spectrum, a long-path UV (LPUV) system and an
active/passive millimeter-wave instrument that will
operate over the 75-1 10 GHz window. This report
will discuss how we expect the synergistic capability
to work and will describe in some detail the design
of the millimeter-wave instrument. Field-portable
FT-IR instruments have been used effectively to
monitor a limited number of gaseous pollutants but
are limited by interference from CO2 and H20 and,
for longer hydrocarbon chains, by spectral overlap.
UV instruments, on the other hand, are much more
sensitive but many gases do not exhibit spectral
absorption (emission) in the UV. It is known that
various hydrocarbons, NO,, 03 and other gases have
rotational lines in the 75-1 10 GHz region, and
narrow-bandwidth millimeter-wave instruments are
now being effectively utilized to monitor trace gases
in the stratosphere. Use of a wide-bandwidth
millimeter-wave system is now being proposed for
environmental monitoring at lower altitudes.
are considered in this report include antenna and
front-end mixer selection, active/passive mode
selections and parallel/serial channel tradeoffs. For
this instrument 1200OK (cooled) effective noise is
expected.