Ca. Fernandes et Am. Barbosa, ANALYSIS OF THE RADIATION FROM A CLASS OF FINITE-LENGTH STRUCTURES USING THE WIENER-HOPF FORMULATION - APPLICATION TO A MULTI-FILAR HELIX, Journal of electromagnetic waves and applications, 8(7), 1994, pp. 909-931
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.