Keeping satellite communications secure is becoming more important as space becomes increasingly crowded.
Military and government satellites must continue sending and receiving information even when opponents try to block or intercept their signals.
Now, engineers at MIT Lincoln Laboratory have developed a new type of antenna that could provide stronger protection while using much less power, making it ideal for small satellites.
The new design is aimed at tactical satellite communications, which focus on maintaining reliable communications in hostile environments.
One growing challenge comes from the increasing number of satellites in low Earth orbit, where thousands of small satellites operate close to our planet.
Because these satellites are small, every gram of weight and every watt of power matters.
Traditional satellite antennas can struggle when signals are deliberately jammed or when other radio signals create interference.
One solution is to use adaptive antenna arrays. Instead of using a single antenna, these systems combine many small antennas that work together. They can quickly change the shape and direction of their radio beams to avoid interference or reduce the effect of jamming.
However, these advanced antenna systems are usually large, heavy, expensive, and require a lot of power. This makes them difficult to install on small satellites.
To solve this problem, the MIT team developed a new prototype called the Hosted Nimble Beamforming Anti-Jam Reflectarray, or HoNi BAJR.
Unlike traditional antenna arrays, the new system uses a flat surface made of many small reflective elements. When radio signals strike this surface, each tiny element slightly changes the signal before reflecting it.
By carefully controlling all of these elements together, the antenna can steer its communication beam in different directions and reduce interference.
One major advantage is its simple design. Traditional antenna arrays often need a separate amplifier for every antenna element, which increases cost, size, and power use.
The reflectarray design removes the need for hundreds of individual amplifiers by collecting signals through a separate feed antenna. As a result, the system uses about 95% less power than many conventional antenna arrays.
The prototype contains 256 small reflective elements and is designed to fit on a typical small satellite. During laboratory testing, it successfully received signals across a wide viewing angle and was able to split its communication beam to serve multiple users at the same time without noticeable signal loss.
The researchers also tested ways to protect communications from interference. Instead of blocking only one source of unwanted signals, the antenna can create larger protected areas where interference is greatly reduced. Although this approach showed promise, it still needs improvement because even small changes in the signals can affect performance.
The next major challenge is calibration. Calibration allows engineers to precisely measure and adjust how the antenna behaves so that all of its reflective elements work together accurately. Because scanning reflectarrays are still a new technology, there is very little previous research to guide this process.
The research team believes this new antenna has significant potential for future satellite networks.
With further improvements, it could provide secure, reliable communications for small satellites while reducing weight, power use, and cost. As more satellites are launched into low Earth orbit, technologies like this may become an important part of protecting communications in space.
