Generalized Multimode Scattering Parameter and Antenna Far-Field Conversions

A general technique is presented to transform multimode and mixed-mode scattering parameters (S-parameters) between arbitrary sets of equivalent passive N-port networks, and transform antenna far-fields between N-port antennas with different sets of multimode or single-ended excitations. The technique makes use of simple transformation matrices, and makes provision for general multimode ports, coupled and uncoupled multiconductor transverse electromagnetic ports, and mixed-mode networks containing both differential ports and single-ended ports. A quadraxially fed multimodal antenna is analyzed as example.