Quarter wavelength absorber

  • Eccosorb SF
  • Reflection off the front face is modified in amplitude and phase based upon the material properties.
  • Transmitted wave is modified in amplitude and phase by transmission through front face, propagation through material, reflection off backing surface and transmission back through front face.
  • When primary reflection and secondary reflection are identical in magnitude and 180 degrees out of phase, reflection minimum occurs. Phase cancellation occurs when thickness of material is ¼ wavelength. Hence Eccosorb SF or any other single layer homogeneous absorber is inherently narrowband.