Edwin L. Aguirre
UMass Lowell’s Submillimeter-Wave Technology Laboratory (STL) has received a renewal grant worth $23 million over five years from the U.S. Army’s National Ground Intelligence Center.
“This grant is a continuation of our program to assist the government in acquiring and analyzing surveillance radar imagery,” says Physics Prof. Robert Giles, who directs the STL. “It is a testament to and recognition of our high level of expertise in the field. Our research is focused on using terahertz frequency sources and receivers to scale the Army’s millimeter-wave and microwave airborne radar systems.”
For the past 30 years, the STL has been at the forefront of terahertz transmitter and receiver technologies and has pioneered the design and fabrication of broadband solid-state multiplier sources, high-power carbon dioxide and far-infrared lasers and laser/microwave hybrid systems. The Lab has developed and applied these technologies in the areas of military surveillance, homeland security, medical diagnostics and scientific and academic research.
represents scientists and engineers from every University discipline, and every aspect of our investigative studies requires interdisciplinary collaborations,” says Giles.
From the Lab to the Battlefield
In 1979, then-STL director (now science adviser) Prof. Jerry Waldman recognized that emerging terahertz source/receiver technologies could be used to simulate the military’s sophisticated microwave radar systems in the laboratory. These simulations could then be used to obtain characteristic radar fingerprints of aircraft, ships, tanks, trucks and other tactical vehicles at low cost and very high accuracy. Such radar fingerprints are useful for quickly identifying whether an incoming object in the battlefield is a friend or foe.
Researchers at STL spent more than a decade engineering and fabricating scale versions of the military radars and high-precision models of actual targets, as well as measuring and analyzing the resulting radar backscatter.
“As a member of ERADS, the Expert Radar Signature Solutions consortium developed by the National Ground Intelligence Center, we and our government sponsors are the only research program that uses terahertz-frequency measurement systems to collect real-world radar signature data,” says Giles in explaining the lab’s unique position.
ERADS also includes researchers at the Aberdeen Proving Grounds and the University of Virginia.
Today, scaling airborne radar imagery at terahertz frequencies requires that STL researchers build accurate models, even replicating non-metallic materials. The challenge also includes acquiring the images in laboratory-scale environments on desert, soil, asphalt, concrete or other terrains amid ground clutter found in actual military operations.
In addition to its work for the Army, the STL has used its unique capabilities to fulfill radar measurement requests from other Department of Defense agencies as well as defense-related laboratories and companies, including MIT Lincoln Lab, Boeing, Lockheed-Martin and Raytheon.
Diagnosing Cancer at Terahertz Wavelengths
STL’s efforts have also successfully spun-off to medical applications, especially in detecting non-melanoma skin cancer.
Non-melanoma skin cancer is the most common form of cancer, with approximately a million new cases diagnosed each year. It is also nearly 100 percent curable if diagnosed and treated in time. Currently, early detection of skin cancer is based on visual medical assessment and diagnosis requires a biopsy.
Terahertz imaging has the potential to offer a relatively safe, non-invasive medical imaging technique for detecting different types of human skin cancers. Unlike X-rays, terahertz rays are non-ionizing and have no known harmful effects on living tissue. Also, the fact that terahertz rays have a shorter wavelength than microwaves implies an inherently higher spatial resolution for imaging applications.
STL post-doctoral researcher Cecil Joseph has demonstrated that there is sufficient contrast between healthy and cancerous tissue at terahertz frequencies. This could lead to a simpler and more cost-effective diagnostic tool for treating skin cancer.
“With sufficient external funding, we are hoping to build the hardware required for clinical studies,” says Giles.