  This paper introduces a multi-beam secure communication scheme for mixed
near-field and far-field (hNF) scenarios, primarily designed to address the
challenges faced by sixth-generation (6G) networks in simultaneously managing
near-field and far-field communications. This method significantly reduces the
signal quality at eavesdroppers(Eves) while ensuring high-quality reception for
legitimate users, effectively enhancing communication security. At the
transmitter, this study employs multi-beam symbol-level directional modulation
to ensure secure and reliable transmission in a mixed eavesdropping
environment. Given the uncertainty about eavesdropper information, the
transmission beamforming vectors are specially designed to meet specific
symbol-level constraints, thereby ensuring effective reception for legitimate
users. Experimental and simulation results demonstrate the effectiveness of our
approach in improving secrecy performance, reducing transmission power, and
enhancing energy efficiency, offering a practical solution to the security
challenges faced by future wireless networks.
