ANALYSIS OF THE RADIATION FROM A CLASS OF FINITE-LENGTH STRUCTURES USING THE WIENER-HOPF FORMULATION - APPLICATION TO A MULTI-FILAR HELIX

An approximate procedure is proposed, to characterize the radiation fr om a class of open finite-length Wiener-Hopf (WH) structures, that is useful when a complete account of the direct feed radiation and of the open end effects is required, but the corresponding (exact) modified WH equation does not allow a closed-form evaluation. This procedure co nsiders the finite-length problem as an appropriate superposition of t wo related semi-infinite WH problems, each one leading to an exact sol ution. It takes into consideration the discrete modes and the continuo us spectrum waves launched at the feed end, and also at-the structure open-end. The usefulness of this procedure is tested in the case of a finite-length multi-filar helix, fed by the open-end of a circular wav eguide of the same diameter. Theoretical radiation patterns show a sat isfactory agreement with experimental results.