A broad-banded folded monopole antenna

Electrically short folded monopole antennas with lumped mutual coupling between driven and folded sections are considered, showing that the input radiative impedance exhibits a resonance frequency depending upon the sign and magnitude of the coefficient of coupling. If extended to "
n
-folded" monopoles with separate lumped mutual couplings, the analysis shows the input radiative impedance will exhibit
n
staggered resonance frequencies and bandwidth broadening.