Modified Wilkinson power divider using coupled microstrip lines and shunt open-ended stubs

The design of a modified Wilkinson power divider for wideband applications is presented. Instead of using a T-junction at the input port of the traditional design, the proposed divider uses broadside-coupled microstrip to slotline configuration to extend the impedance matching bandwidth at the input port. Moreover, a coupled structure with two isolation resistors and two open-ended stubs is used to enhance isolation and matching of the output ports across a wide band. The device has an overall dimension of 40 × 70 mm using the substrate Rogers RO4003 (dielectric constant = 3.38 and thickness = 0.508 mm). The simulated and experimental results show more than 100% fractional bandwidth assuming 16 dB of isolation and 10 dB of return loss as the reference. The device has equal power division between the two output ports with <;0.2 dB amplitude imbalance and <;2° phase imbalance across the band 1-3 GHz.