NASA Technical Reports Server (NTRS) 20140002359: Transition-Edge Hot-Electron Microbolometers for Millimeter and Submillimeter Astrophysics

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by  NASA Technical Reports Server (NTRS)

coupling between the first and second the gain, with the upper bound limited This work was done by Timothy F.
microstrip antennas with and without often by the largest practical dimen- Kennedy, Patrick W. Fink, Andrew W. Chu,
the DFR. Typically, a DFR is designed for sions that can be tolerated for a given and Gregory Y. Lin of Johnson Space Center.
use at a particular frequency; however, application. The maximum theoretical Further information is contained in a TSP
testing of a DFR indicated a relatively im provement in gain for a single ring is (see page 1).
wide operational bandwidth of approxi- 9.5 dB. Experimental results are within This invention has been patented by NASA
mately 8.2%. Wider bandwidth opera- 0.9 dB of this theoretical value. Adding U.S. Patent No. 8,384,614. Inquiries con-
tion and multi-band operation are antic- rings increases gain, and theoretically, cerning nonexclusive or exclusive license for
ipated by extending the known art of improvements of 10 to 13 dB above its commercial development should be ad-
conventional Fresnel rings to the DFRs. that of the primary antenna gain can dressed to the Patent Counsel, Johnson Space
Increasing the number of rings used be achieved with two- and three-ring Center, (281) 483-1003. Refer to MSC-
to construct a DFR antenna increases versions. 24525-1.
Transition-Edge Hot-Electron Microbolometers for Millimeter
and Submillimeter Astrophysics
New instruments promise to expand the investigation of cosmic microwave background radia-
tion and its polarization to get better insight into the evolution of the universe.
Goddard Space Flight Center, Greenbelt, Maryland
The millimeter and the submillime- stegrated with antennas via microstrip tector dimensions to be much smaller
ter wavelengths of the electromagnetic transmission lines, and with SQUID (su- than a wavelength, so the technique can
spectrum hold a wealth of information perconducting quantum interference be extended across the entire mi-
about the evolution of the universe. In device) readouts. The small volume of crowave, millimeter, and submillimeter
particular, cosmic microwave back- the absorber and TES produces a short wavelength ranges. The circuits are fab-
ground (CMB) radiation and its polar- thermal time constant that facilitates ricated using standard microlitho-
ization carry the oldest information in rapid sky scanning. graphic techniques and are compatible
the universe, and provide the best test The THM consists of a thin-film metal with uniform, large array formats. Un-
of the inflationary paradigm available absorber overlapping a superconducting like traditional monolithic bolometers
to astronomy today. Detecting gravity TES. The absorber forms the termina- that make use of micromachined struc-
waves through their imprint on the tion of a superconducting microstripline tures, the THM employs the decoupling
CMB polarization would have extraor- that carries RF power from an antenna. between electrons and phonons at mil-
dinary repercussions for cosmology The purpose of forming a separate ab- likelvin temperatures to provide ther-
and physics. sorber and TES is to allow flexibility in mal isolation. There is no fragile mem-
A transition-edge hot-electron micro - the optimization of the two components. brane in the structure for thermal
bolometer (THM) consists of a super- In particular, the absorbing film’s im- isolation, which improves the fabrica-
conducting bilayer transition-edge sen- pedance can be chosen to match the an- tion yield.
sor (TES) with a thin-film absorber. tenna, while the TES impedance can be This work was done by Wen-Ting Hsieh,
Unlike traditional monolithic bolome- chosen to match to the readout SQUID Thomas Stevenson, Kongpop U-yen, and Ed-
ters that make use of micromachined amplifier. This scheme combines the ad- ward Wollack of Goddard Space Flight Cen-
structures, the THM em ploys the decou- vantages of the TES with the advantages ter; and Emily Barrentine of the University of
pling between electrons and phonons at of planar millimeter-wave transmission Wisconsin at Madison. Further information
millikelvin temperatures to provide ther- line circuits. is contained in a TSP (see page 1). GSC-
mal isolation. The devices are fabricated Antenna-coupling to the detectors via 16656-1
photolithographically and are easily in- planar transmission lines allows the de-
18 NASA Tech Briefs, January 2014