Rigorous Analysis and Investigation of the Bandwidth Broadening Mechanism in a Compact Power Divider With Physical Port Isolation

This paper proposes a compact power divider with simultaneous physical port isolation and wideband operation based on the simple Wilkinson power divider (WPD) configuration. Rigorous analysis based on the even- and odd-mode bisected networks has been performed to investigate the relationship between the design parameters and the overall performance. Theoretical analysis revealed that the impedance and isolation bandwidth are directly related to the reflection coefficients of the even- (
$\Gamma _{\text {e}}$
) and odd-mode (
$\Gamma _{\text {o}}$
) bisected networks. Simultaneous broadening of the impedance and isolation bandwidth is possible through the optimum choice of design parameters which confines the trajectories of the
$\Gamma _{\text {e}}$
and
$\Gamma _{\text {o}}$
in the low constant-Q region on the Smith Chart. Experimental verification by the prototype designed at 1 GHz exhibited the widest overall system bandwidth (43.2%) and the lowest total electrical length (140.8°) as compared to the previous state-of-the-art WPD’s with physical port isolation.