Design of wideband bandpass power divider with high rejection level stopband

In order to reduce the size of communication system, a wideband filtering power divider with high rejection level in the lower and upper stopband is proposed in this paper. Two bandpass filters (BPF) are utilized to replace the quarter-wavelength transmission line in the traditional Wilkinson power divider. A resistor is adequately arranged for isolation and impedance matching. Even-and odd-mode method is applied to obtain design equations of the proposed circuit. Finally, a prototype power divider with central frequency of 2.97 GHz, and the fractional bandwidth (FBW) of 62% is designed and fabricated for verification. Measured results indicate the attenuation level is larger than 38.4 dB in the lower stopband, and larger than 31.4 dB (2.67 f₀).