Reconfigurable top-loaded monopoles using stacked space-filling curves

Abstract

Metallic paths, structured after space-filling curves, are shown to be useful for the top-loading of electrically small monopolar elements, when utilized with shorting posts at the curvespsila end-points. When scaled versions of these top-loaded monopoles are stacked on top of each other, dual-band resonances can be achieved and these dual-bands can be designed through the proper scaling of the height and footprint dimensions. By allowing the posts to act as either open or closed switches, different modes can be excited such to provide either single-band or multi-band, vertically polarized performance and in certain configurations the polarization may be ldquoswitchedrdquo from vertical to horizontal polarization within the same frequency band. For its electrically small size, these top-loaded monopolar elements provide relatively wide-band characteristics yet when providing horizontal polarization, these elements are very narrow band due to the low-profile nature of the proximity-fed dipolar element. Further investigation into the different reconfigurable modes is currently being conducted, as well as the effects of utilizing switches in place of the shorting posts, as presented here. Such effects, as well as experimental validation will be included in the presentation.