Fast evaluation of the Sommerfeld integrals for the stratified media Green's function with field and source points in different layers

A novel idea is proposed and tested in the paper for fast Green's function calculation in the stratified media with the field and source points located in the different layers. A low pass filter window function is used to create an artificial steepest descent path (ASDP). This ASDP is then used to accelerate the Sommerfeld integration by which the Green's function can be obtained. Numerical experiments have been done to support the idea.