This paper presents a lumped-element Wilkinson power divider (WPD) using LC-ladder circuits composed of a capacitor and an inductor, and a series LR/CR circuit. The proposed WPD has only seven elements. As a result of designing the divider based on an even/odd mode analysis technique, we theoretically show that broadband WPDs can be realized compared to lumped-element WPDs composed of Π/T-networks and an isolation resistor. By designing the WPD to match at two operating frequencies, the relative bandwidth of about 42% can be obtained. This value is larger than that of the conventional WPD based on the distributed circuit theory. Electromagnetic simulation and experiment are performed to verify the design procedure for the lumped-element WPD designed at a center frequency of 922.5MHz, and good agreement with both is shown.

In this paper, we propose a design method of compact multi-way Wilkinson power divider with a multiband operation for size reduction and band broadening. The proposed divider consists of multisection LC-ladder circuits in the division arms and isolation circuits between the output ports. To validate design procedures, we fabricated a trial divider at VHF band. The circuit layout of the trial divider was decided by using an electromagnetic simulator (Sonnet EM). Because the proposed divider consists of lumped element circuits, we can realize great miniaturization of a circuit area compared to that of the conventional Wilkinson power divider. The circuit size of the trial divider is 35 mm square. The measurement results for the trial divider by using a vector network analyzer indicates a relative bandwidth of about 60% under -17 dB reflection, flat power division within ±0.1 dB, and very low phase imbalances under 1.0 degree over the wide frequency range.