A Novel Branch-Line Coupling Topology

This article presents a novel branch-line coupling topology, which offers superior performance to the conventional branch-line coupler. The structure of the proposed network is very simple; in fact, only one additional transmission line element is required to modify the ever-present branch-line coupler in such a way that the bandwidth is enhanced by roughly 25%. The proposed structure is analyzed using an even-odd analysis, and closed-form expressions for the dimensioning of the network parameters are given. The transmission-line impedances are equal or very close to the system's impedance, and there is no need for very low or high transmission-line impedances.

Automated summary

This article presents a novel branch-line coupling topology that outperforms the conventional branch-line coupler. The proposed network structure is simple, requiring only one additional transmission line element to enhance the bandwidth by approximately 25%. The analysis of the proposed structure is based on even-odd analysis, and closed-form expressions for dimensioning the network parameters are provided. The transmission-line impedances are equal or very close to the system's impedance, eliminating the need for very low or high transmission-line impedances.