A low cost capacitor approach for suppressing resonance in power distribution networks

Resonances in power distribution network are the major cause of voltage fluctuation and noise problems. In this paper, a new method that suppresses impedance peak is proposed. The proposed method uses a high series resistance (HSR) capacitor in parallel to regular bypass capacitors. By selecting the parameters so that the series resonance frequency of the HSR capacitor equals to the anti-resonance frequency of the bypass capacitors, current path will be formed through the HSR capacitor, suppressing the impedance peak. Relatively low required capacitance in this configuration enables low cost fabrication of the HSR capacitor. Experimental measurements using a double-side printed circuit board have shown that the proposed method lowers the peak impedance by 10-fold and reduces radiation noise by 10dB.