Eavesdropping Measurements for Applications in Office Environments at Low THz Frequencies

Low terahertz (THz) frequencies are promising candidates for future wireless communication systems. Due to high path losses at those frequencies, highly directive antennas can be used to compensate the path losses thus making eavesdropping challenging. However, previous work has shown that eavesdropping is still possible even if antennas with pencil beams are used. In this article, eavesdropping possibilities are evaluated with respect to common objects in office environments–a coffee cup, a thermos, and a laptop–by investigating the scattering properties of these objects. For the coffee cup and the thermos, angle-independent reflection losses are given. The laptop has the lowest reflection losses of approximately 5 dB if it is placed to reflect the signal in a specular way. Furthermore, the results are analyzed in terms of secrecy capacity and blockage, revealing good eavesdropping opportunities when the thermos is used. If the object is placed outside of the line-of-sight path, the blockage drops down to zero. However, especially for the thermos the secrecy capacity is still below 0.8 in this case. For the other objects, a direct eavesdropping where Eve is directly oriented toward Alice results in a lower secrecy capacity in most of the cases.