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CDL and Radio Astronomy

A History of Innovation

The Central Development Laboratory has played a key role in NRAO projects, dating back to the design of the Very Large Array (VLA), which was commissioned in 1980. At the time, the VLA was the most sophisticated radio telescope in the world and CDL designed its correlator, a special-purpose computer that processed the signals from the 27-antenna array to form a single, high-resolution image (i.e., interferometry). This correlator was used until the Expanded VLA (EVLA) was brought online in 2010.

Subsequently, CDL designed the correlator for the Observatory’s Very Long Baseline Array, another interferometric telescope commissioned in 1994 consisting of 10 identical antennas, separated by distances from 200 km to l8,600 km — truly a transcontinental telescope, with the longest baseline between Mauna Kea, Hawaii and St. Croix, Virgin Islands.

CDL personnel went on to lead an international team that designed, built, and installed the correlator for the Atacama Large Millimeter/submillimeter Array (ALMA), located at an elevation of 5000 m in the Atacama Desert of northern Chile and commissioned in 2011.

CDL has also made some of the highest-performing cryogenic low-noise amplifiers (CLNAs) ever produced. Low noise amplifiers set the performance of the overall receiver—a crucial role given the extraordinarily weak signals radio telescopes collect. The best CLNAs are designed to add very little noise to the system and have high amplification, and CDL has excelled at doing this. There are over a thousand of CDL’s CLNAs in radio telescopes around the world.

Investments in Radio Astronomy Technology

As a Federally Funded Research and Development Center (FFRDC) under the National Science Foundation (NSF), NRAO is encouraged to patent radio astronomy technology when appropriate and to find commercial partners for licensed production of products based on our patents that can enhance US industrial competitiveness and national security.

To this end, as part of its mission to improve the performance of radio astronomy receivers, CDL developed a novel technology called “Reflectionless Filters”, which were developed and patented in 2013 by CDL research engineer Dr. Matt Morgan. Reflectionless filters improve the performance of all sorts of electronic devices—not just radio astronomy receivers—and have been under licensed production with our industrial partner, Mini-Circuits of Brooklyn, NY for several years. Over one hundred companies have bought reflectionless filters for use in commercial and national security products, and royalties have been returned to NRAO as part of this licensing agreement.

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