Secure Pinching Antennas-Aided Wireless Communication System

In this paper, a robust pinching antenna-based scheme for ensuring secure wireless communication systems is proposed. In the presence of several malicious eavesdroppers targeting the legitimate signal of various genuine users, the designed approach exploits the spatial flexibility of a pinchingantennas system (PAS) composed of several waveguides and pinching antennas to provide secure communication to legitimate nodes. In particular, multiple pinching antennas can be positioned in each waveguide spanning a long distance, providing additional degrees of freedom and flexibility to adjust the channel response with respect to the various users and eavesdroppers. By virtue of semidefinite programming, an optimization problem aiming at optimizing the transmit beamforming to minimize the total transmit power, subject to secrecy constraints, is formulated and solved. The obtained results demonstrate the total transmit power reduction by increasing the number of antennas and waveguides subject to the same secrecy constraints. Furthermore, the proposed scheme outperforms the benchmark one, consisting of an array of co-located transmit antennas at the base station, when either a direct link from the latter to the users is blocked or when the eavesdroppers are located in the line of sight of the legitimate users.