Two of Georgia Tech's software-defined, electronically reconfigurable Agile Aperture Antennas (A3) were demonstrated in an aircraft during flight tests. The low-power devices can change beam directions in a thousandth of a second. One device, looking up, maintained a satellite data connection as the aircraft changed headings, banked and rolled, while the other antenna looked down to track electromagnetic emitters on the ground.
In addition to rapidly altering its beam direction, the antenna's frequency and polarization can also be changed by switching active components. Beyond its ability to be easily reconfigured, the low power consumption and flat form make the A3 ideal for aircraft such as UAVs that have small power supplies and limited surface area for integrating antennas. Composed of printed circuit boards, the antenna components weigh just two or three pounds.
To track the satellite, the antenna uses an inertial measurement unit to provide information about the aircraft's pitch, roll and yaw — as well as its longitude, latitude, and altitude. That information is sent to a controller that turns elements off and on to the change the beam direction to maintain communication. Before takeoff, the researchers had programmed into the device the location of the commercial satellite with which it was communicating.