The conventional wisdom in ham circles is that thicker elements result in broader bandwidth. That goes along nicely with structural stiffness, and thus most VHF Yagi-Uda antennae are made with their elements cut from tube instead of rod, for example.
I'm not sure which changes you made exactly, but I wouldn't be surprised if the end effect was thickening the relevant portions.
I'm not sure which changes you made exactly, but I wouldn't be surprised if the end effect was thickening the relevant portions.