Wideband power dividers with improved upper stopband using coupled lines

Three novel wideband microstrip power dividers with improved upper stopband using coupled lines are proposed in this study. Wide upper stopband can be obtained by the multiple transmission zeros realised by the stepped coupled lines. Isolation resistors are proposed to achieve wideband power division isolation for the power dividers. Three wideband microstrip power dividers with division bandwidths of 47% (1.76–2.84 GHz), 47% (1.75–2.83 GHz), and 47.8% (1.75–2.85 GHz) are designed and fabricated. The upper stopband for the last two power dividers can be extended up to five and six octaves.