  In this letter, we study the reconfigurable intelligent surfaces (RIS) aided
full-duplex (FD) communication system. By jointly designing the active
beamforming of two multi-antenna sources and passive beamforming of RIS, we aim
to maximize the energy efficiency of the system, where extra self-interference
cancellation power consumption in FD system is also considered. We divide the
optimization problem into active and passive beamforming design subproblems,
and adopt the alternative optimization framework to solve them iteratively.
Dinkelbach's method is used to tackle the fractional objective function in
active beamforming problem. Penalty method and successive convex approximation
are exploited for passive beamforming design. Simulation results show the
energy efficiency of our scheme outperforms other benchmarks.
