Common-Mode Noise Absorption Circuit Using Double-Sided Parallel-Strip Line

This letter presents a common-mode noise absorption (CMNA) circuit using the double-sided parallel-strip line (DSPSL). The circuit behaves as a pair of conventional transmission lines (TLs) under differential-mode (DM) excitation. The common-mode (CM) noise is suppressed and absorbed by the surface-mounted resistors between the two TLs. Based on analytical design equations, the values of the surface-mounted resistors can be calculated, and a high-efficiency CM absorption at the wide frequency band can be obtained. Finally, a practical CMNA circuit with wideband CM absorption is designed and fabricated to verify the design theory.