Carbon nanotubes (CNTs) properties and applications are one of the most inno- vative and interesting research areas in physics and engineering. The electromagnetic behaviour of CNTs composites and plastic material such as PE and PMMA has been analized in several works. Recent works have highlighted how CNTs can be effectively applied in electromagnetic interference (EMI) as high shielding material. Basically, this is due to their high aspect ratio and their tunable conductivity, which allows the electrical percolation (with a little number of CNTs). It is crucial to understand and control the electromagnetic properties of these materials to apply them to devices design in several research fields. A buckypaper is a thin sheet made only with an aggregate of CNTs. A potential application is in shielding technology to protect electronic devices from electromagnetic interferences: for istance CNTs shields could be applied to avoid radar detection of militar aircrafts, or to prevent equipment damaging and unintended setting modication. At the same time, CNTs shields could be applied to avoid radar detection of militar aircrafts. Moreover, in the next years these structures could have a wide application in nano- and bio-science: potential application in the electromagnetical shielding concern nanoelectronis devices, nano-biomedical imaging and sensing or, in the near future, the protect medical equip- ments from high-frequency radiations. This paper studies the shielding efficiency of a buckypaper interposed between a multifrequency source and a electromagnetic waved detector. Our analysis is focused only on X Band frequencies.