A Miniaturized Filtering Power Divider With High Selectivity and Wide Stopband Based on 3-D Heterogeneous Integration Technology

Based on a novel circuit of the lumped filtering power divider (FPD), a miniaturized FPD with wide stopband, high selectivity and high isolation using 3D heterogeneous integration technology is proposed. The lumped circuit can realize the filtering characteristics of transmission zeros (TZs) controllable, bandwidth controllable, and rejection controllable. 3D heterogeneous integration technology in this brief is the integration of organic substrates and integrated passive device technology by the bump flip-chip technique. In this technology, planar inductors with low Q-factor are replaced by 3D inductors with organic substrates. The measured results show the proposed FPD at the center frequency f(0) of 3.75 GHz has a 26.7% 15-dB return loss fractional bandwidth (FBW). Its 20-dB and 30-dB upper stopband can be extended to 4.19 f(0) (15.71 GHz) and 3.84 f(0) (14.39 GHz). Its 25-dB lower stopband ranges from 0 to 2.74 GHz. And the volume of the proposed FPD is 0.037 x 0.02 x 0.0045 lambda(3)(0) , where lambda(0) is the air wavelength at f(0).