Miniaturized lumped-distributed wideband balun using double-sided CPW structure

This paper presents a miniaturized wideband balun using CPW structure with lumped elements. Although a low frequency (low or mid-MHz) balun is considered hard to be physically small or to have wide bandwidth, the proposed design utilizes lumped elements to reduce the physical size while double-sided CPW structure provides wide bandwidth in low frequency band (470-630 MHz). Having the proposed balun fabricated with FR-4 board, both simulation and measured results are presented to illustrate its performance.