Advances in Holographic Impedance Surfaces for Antennas

  • Published
  • By Maria Callier
  • Air Force Office of Scientific Research
ARLINGTON, Va. --  Air Force-funded researchers at HRL Laboratories in Malibu, California are working on holographic impedance surfaces for antennas, which will give aircraft improved aerodynamics.

"We are using a design technique that is similar to how people make holograms," said Dr. Daniel F. Sievenpiper, lead researcher. "We can potentially make antennas that are completely flush with the surface of the aircraft, but have the same or better performance as those that protrude out of the aircraft using today's techniques," he said.

Sievenpiper and his team at HRL are building the surfaces out of metallic materials on a substrate. The structures perform similarly to an object covered with the surface impedance.

They have extended their work with funding from the Air Force Office of Scientific Research under the guidance of Program Manager, Dr. Arje Nachman.

"An equally attractive prospective benefit offered by these interesting surfaces is that if the tail of an aircraft obstructs the beam of an antenna (radar) then the tail can be covered by a suitably crafted impedance surface in such a way that the antenna beam "flows" around the tail as if the tail weren't there," said Nachman.

The HRL team is now trying to extend the capabilities of the electromagnetic impedance and enable practical implementations of it. They plan to create new kinds of unit cells and are also seeking new mapping techniques that allow those cells to be positioned over complex objects. To do that, they use a variety of simulations, large-scale electromagnetic calculations, and measurements.

Their next steps are to continue fundamental research and in Sievenpiper's case, collect honors for the work already completed. At a ceremony last month in Chicago, he received the International Union of Radio Science (URSI) Isaac Koga Gold Medal for outstanding contributions of a scientist under 35. Sievenpiper was honored "For contributions to the development of artificial impedance surfaces and conformal antennas." The award covers a range of work that included the early development of artificial magnetic conductors while Sievenpiper was a graduate student at the University of California at Los Angeles. It also covers the development of tunable impedance surface and holographic artificial impedance surfaces at HRL.

In his acceptance speech, Sievenpiper stated, "I am truly honored to accept the Isaac Koga Gold Medal, and I am humbled to be considered among the legacy that the URSI represents. In the many decades since its inception, this organization has played an important role in both the scientific and practical aspects of electromagnetics.