  In this correspondence, we propose an unmanned aerial vehicle (UAV)-enabled
integrated sensing and communication (ISAC) system, where a full-duplex UAV
equipped with uniform planar array (UPA) is adopted as a base station for the
multiuser downlink communications, while sensing and jamming a passive ground
eavesdropper. The goal of this work is to maximize the sum secrecy rate of
ground users subject to the constraints of sensing accuracy and UAV's
operational capability by jointly optimizing the transceiver beamforming and
UAV's trajectory. To this end, we develop the algorithmic solution based on
block coordinate descent (BCD) and semidefinite programming (SDP) relaxation
techniques, whose performance is verified via simulations indicating its
efficacy in improving communication security with the sufficient mission
period.
