Different　from　the　conventional　phased　array　radar,　a　frequency　diverse　array　(FDA)　applies　additional　frequency　shift　across　the　array　elements,　yielding　a　range-angle-dependent　transmit　beampattern　that　provides　a　huge　potential　opportunity　for　target　estimation　and　range-dependent　clutter　and　interference　suppression.　Generally,　the　conventional　FDA　employs　a　linear　small　frequency　increment,　forming　a　time-varying　＂S＂-shape　range-angle　beampattern,　which　is　range-angle　coupled.　In　this　article,　a　range-angle　transmit　beampattern　synthesis　method　for　FDA　based　on　frequency　offset　optimization　is　proposed.　Particle　swarm　optimization　(PSO)　is　adopted　in　the　FDA　element　frequency　increment　design　to　achieve　a　dot-shaped　transmit　beampattern.　Meanwhile,　matched　weights　are　designed　for　time-modulation　compensation.　Numerical　simulation　results　demonstrate　that　the　proposed　approach　achieves　better　time-invariant　performance　over　other　FDA　frameworks.