Mitigation of common mode noise in bent differential transmission line using curved PBG unit cell

A curved photonic band gap (PBG) unit cell loaded bent differential line is proposed to suppress the differential-to-ommon mode conversion noise. The PBG unit cell, loaded at the bend is designed and optimized to provide the required delay characteristic on the inner transmission line of a differential line. An LC equivalent circuit of curved PBG unit cell is proposed and constituent lumped element parameters are calculated. The realized PBG loaded bent differential line exhibits a measured mode conversion noise below 220 dB from DC to 6 GHz demonstrating a common mode noise suppression of around 9 dB.