It is very likely to be that if you think about a space antenna, the image that appears in your mind is a parabola that sends electromagnetic waves toward the Earth or the deep space. An antenna, as it appears, is a metallic structure that captures and/or transmits radio electromagnetic waves. Antennas come in all shapes and sizes from little ones that can be found on your roof to watch TV to really big ones that capture signals from satellites millions of miles away (figure 1). The antennas that space satellites uses are a special bowl shaped antenna that focuses signals at a single point called a parabolic antenna. The bowl shape is what allows the antennas to both capture and transmit electromagnetic waves.
But what if this concept of capturing and/or transmitting electromagnetic waves would be performed in a slightly different way? Keeping in mind that a parabolic or shaped antennas exploits the geometric features of the reflecting surface to create a narrow and symmetric antenna beam, we can imagine to exploit another concept to perform this signal directivity.
The concept of a Reflect-Array is based on the fact that we want create this narrow and symmetric beam by using flat reflector, or we can say, flat antennas. This is the key point of the Reflect-Array technology. So, does not matter which kind of signal or for which application, a spacecraft would be equipped by a flat antenna. The simple geometric shape of this kind of antenna would allow to reduce the cost of manifacturing, would allow a more flexible allocation on the spacecraft, since it can be conceived foldable, it can be lighter (reduction of mass in Space satellite is very important) and, last but not the least, it can offer a very performing and smart technology for space application.
Another milestone concept of Reflect-Array is that it is constituted by a flat panel that is printed with several metallic patches. Electromagnetic waves can be reflected in different way if they imping of different surfaces, in this case on different patches. The way the signal is reflected by every single patch will determine an ensemble of small signals that interact, they sum up or erase each other. The result is a directive narrow signal as would be produced by a traditional shaped antenna.