Design of Dual-Band Four-Way LC-Ladder Dividers

In this paper, a four-way lumped-element power divider with in-phase output using LC-ladder circuits is described. We propose a four-way LC-ladder divider composed of 2-section LC-ladder circuits between input and output ports, and their output ports are connected through external circuits composed of an LC-ladder circuit and a series LR circuit to obtain satisfactory isolations. By designing the divider based on even-/odd-mode analysis techniques and a complex conjugate impedance matching theorem, the proposed four-way LC-ladder divider can achieve dual-band operation. To confirm the validity of the design method, the divider is designed and fabricated at a center frequency of 300MHz. As results of simulation and experiment, broadband characteristics with a relative bandwidth of about 43% can be obtained. Furthermore, measurement results of the fabricated power divider indicate low reflection, high isolation and extremely flat power division, and good agreement with simulation results.