Far-End Crosstalk Suppression of Serpentine Delay Line Using High-Impedance Line

A high-impedance serpentine delay line (SDL) is proposed to eliminate the far-end crosstalk (FEXT) noise and impedance mismatch encountered in the nominal-impedance SDL in this article. The high-impedance SDL has a high value of characteristic impedance compared to the characteristic impedance of the nominal-impedance SDL. By comparing the FEXT noises of the nominal-impedance SDL and the high-impedance SDL, the high-impedance SDL significantly reduced the value of the FEXT noise from 0.00349 to 0.0009 V. It also reduced the value of the reflection coefficient from -10 to -18dB and decreased the value of the far-end coupling coefficient from -25 to -31dB. Furthermore, it restored the value of the characteristic impedance to the nominal value of 50 Ω. The nominal-impedance and high-impedance SDL were fabricated and measured to confirm the proposed idea. Excellent agreement between the simulation and measurement results proved that the idea is feasible.