A sampling method and a data recovery circuit using the same are provided. The handle assembly includes a spindle and a handle. An inflation member receives airflow from the rescuer to inflate the inflatable portion. Each antenna element is connected to a multiplier with a single real-valued coefficient, which is determined by properly selecting number of points on a u-v plane defined for simplifying the design procedure according to the design algorithm of the present invention. A second portion of the second beam passes through a diffuser and onto a position detector which produces a first signal in response. The transmitting portion is provided between the exiting window and the surface light-emitting element, and the light passes through the transmitting portion.