a miniaturized nested double stage hybrid coupler

A miniaturized nested double-stage 3db broadband branch-line hybrid coupler proposed in this paper. the structure arrangement is so that at least 50% size reduction was been guaranteed. it is also consists of discontinuous microstrip lines and therefore distributed capacitors to miniaturize the physical size of the hybrid coupler. in previous articles use two stage of hybrid couplers in the form of next to each other to increase the band width but in this paper the discontinuous microstrip lines of second stage place within the empty space of the first stage of hybrid. generally two conventional single stage hybrid coupler are connected in series form for obtaining wide bandwidth, in this paper for considerable size reduction, two single-stage 3db hybrid have been connected in the nested form .the size reduction for a proposed topology is 57% in comparison with convntional double-stage branch-line coupler