The ripple modifier produces a concentric rippling effect in an object’s geometry. You can use either of the two different ripple effects of a combination of both. Ripple uses a standard gizmo and center, which you can transform to increase the number of ripple variations. The Ripple space warp has similar features.
Step1: create a plane.
Fig. 89
Step2: click on modify tab then select Ripple tool.
Fig.90
Step3: Specify amplitude and wave length.
Fig. 91