Ultrafast multireflector physical-optics beam simulations for the HFI   instrument on the ESA PLANCK Surveyor
  We present the latest results of our fast physical optics simulations of the ESA PLANCK HFI beams. The main beams of both polarized and non-polarized channels have been computed with account of broad frequency bands for the final design and positions of the HFI horns. Gaussian fitting parameters of the broadband beams have been presented. Beam polarization characteristics and horn defocusing effects have been studied. 
Vladimir B. Yurchenko, John Anthony Murphy, and Jean-Michel Lamarre