Differential to common mode conversion suppression using mushroom structure with asymmetric coupled line

Abstract

Right-angle bended differential line using mushroom structure with asymmetric coupled line (ACL) is proposed to suppress the differential to common mode conversion. The mushroom structure and ACL can compensate for self-capacitances and self-inductances of shorter inner line, respectively. Simulated results show that the differential to common mode noise conversion can be maintained under −20dB from DC to 5.96 GHz. Also, transient analysis is conducted to validate the performance of proposed design in time domain, and shows significant suppression of common mode noise. The common mode noise of proposed design is reduced from 129mV to 36mV as compared with conventional right-angle bended differential line. Furthermore, measured results are compared with simulated results and show good agreements.