Characteristic strain (h_c) as a function of observed frequency (f). The upper panel shows a binary with ℳ ∼ 10^8.5 M_⊙ and the observed Keplerian frequency f_k ∼ 10⁻⁸ Hz; while the lower panel shows a binary of ℳ ∼ 10¹⁰ M_⊙ and f_k ∼ 10^−9.5 Hz outside the SKA PTA sensitivity curve. In each panel, blue, orange, and purple lines represent the root mean square of the sGWB generated by all the models with e₀ = 0, 0.5 and 0.9, respectively. The black line corresponds to the sensitivity curve of SKA PTA (white and red noise) 30-year data. The colored dots represent how the signal of an MBHB is distributed across different frequencies when the eccentricity is varied between 0, 0.5 and 0.9.