Design of a planar ultra-wideband four-way power divider/combiner using defected ground structures

This work presents the design of a planar ultra-wideband (UWB) four-way power divider/combiner. A prototype has been fabricated on a printed circuit board and characterized. For achieving the frequency response required in UWB applications, each branch of the divider is conceived as a three-section Chebyshev impedance transformer. The defected ground structure (DGS) technique has been used to obtain the required high impedance lines. The power divider's insertion loss is 1 dB at 3.1 GHz and 2.9 dB at 10 GHz; the input reflection is lower than -10 dB, and the isolation between the output ports is better than 13 dB from 3 GHz to 10 GHz. A back-to-back configuration has been implemented as well. Its insertion loss is lower than 5 dB and its input reflection is lower than -10 dB over the UWB frequency range.