“Phase Centers” of Far Infrared Multi-Moded Horn Antennas

摘要: Multi-moded horn antennas can be used as high efficiency feeds for bolometers when diffraction limited resolution is not required. For example, such horns are proposed the PLANCK Surveyor, a satellite telescope due to launched in 2007 make definite measurements of Cosmic Microwave Background. In previous paper we described an accurate approach involving electromagnetic modelling using rigorous mode matching technique obtain both aperture fields and corresponding far field radiation patterns. this extend description determine “phase center” on large reflecting telescopes. The ill defined individual spatially coherent making up pattern all appear come from different phase centers. best average center location therefore redefined terms virtual beam waist position behind at which focus should located order optimise angular on-axis gain sky. A number alternative techniques locating discussed detail thes paper.