Wideband coupled-line ring hybrids are presented for high power-division ratios. For this, an equivalent circuit to make the characteristic impedance of a transmission-line section lower is firstly investigated, based on a ${\Pi}$ -type lumped-element equivalent circuits. Design formulas of four types of equivalent circuits ( ${L}_{{{\Pi}}}$ -, ${L}_{{T}}$ -, ${L}_{{S2}}$ -, and ${L}_{{S1}}$ -types) are then derived, and $N$ is introduced for more design flexibility and wideband performance. The ${L}_{{S}{{2}}}$ -type with $N= 1$ is composed of one transmission-line section and two identical series inductances at both ends, which cannot be used for the ring hybrids with the high power-division ratios. To avoid the problem, modified ${L}_{{S2}}$ -type ( ${ML}_{{S2}}$ -type) with $N$ is additionally suggested, and that with $N=1$ is intensively discussed. Using two of those, ${L}_{{S1}}$ -type with $N= 2$ and ${{ML}}_{{S2}}$ -type with $N=1$ , the coupled-line ring hybrids with 13- and 11-dB power-division ratios are fabricated. The measured results show good agreement with those predicted.