Synthesis of conventional branch-line couplers with better electrical performance

This paper proposes a method for the synthesis of a Branch-Line coupler with improved bandwidth, in special the range where S21= (−3±1) dB, in relation to the conventional device without increasing its size and complexity. The structure of the proposed device keeps the same degree of simplicity of the conventional case, thereby it is also formed by four quarter-wave lines that, in this study, will be shown to have new and different numerical values for its normalized characteristics impedance when compared to the conventional structure.