A novel wideband balun with a CPW power divider

This paper presents a wideband balun ranging from 1GHz to 2GHz, with a Wilkinson power divider and an inverted phase shifter on a coplanar waveguide (CPW) substrate. A novel structure is proposed with concentric circles. After a series elaborate designs and optimizations based on the software HFSS, The parameters S11, S22, S33 is nearly −20dB, isolation less than −20dB and phase flatness within ± 10° in the operation frequency range. The designs can also be applied to circuits with wideband and low-level requirements for phase. The S parameters are easily tested and the experimental results show that the characteristic is in accordance with simulation