Bended Differential Line Routing Adaptive Designed by Periodic Nonuniform Structure With Ultrawideband Mode Conversion Noise Suppression

In this article, a periodic nonuniform transmission line adaptively optimized by whale optimization algorithm (WOA) is proposed to suppress the differential-to-common mode conversion noise of the differential pair. The phase difference between the inner and outer traces can be compensated by periodic nonuniform structure with slow wave effect, which can reduce the electric length and achieve wideband impedance matching. The proposed nonuniform structure is parameterized by cosine exponential function, while the function coefficients can be optimized by WOA with properties of swarm-based and meta-heuristic. Compared with conventional mode conversion methods, wideband, and steep noise suppression level can be observed with the presented design, Time domain analysis is also conducted to verify the transmission performances. A compensated differential transmission line is fabricated with a suppression level | S_{cd 21} | of −25 dB from dc to 15 GHz.