Comments on “Two-Section Broadband Couplers With Wide-Range Phase Differences and Power-Dividing Ratios”

It is shown that the two-section branch-line coupler proposed in Liu and Lin (2021) corresponds to the cascade connection of two conventional couplers. The design of the two-section coupler can be reduced to that of a conventional single-section branch-line coupler. The wide-range phase-differences of the two-section couplers become ineffective toward larger power-dividing ratios and the two-section couplers have a much-reduced range of power-dividing ratios as compared with the conventional single-section couplers.