Study on noise reduction effect using the decoupling capacitor with resistor on power distribution line

The purpose of this study is to estimate the switching noise reduction effect by using the decoupling capacitor with resistor. By attaching several decoupling capacitors in parallel in the circuit, new anti-resonance peaks appear and it prevents the noise reduction effect. The use of decoupling capacitor with resistor can promise to reduce resonance effects. In this study, the effects of decoupling capacitor with resistor were investigated when it attached to the power-ground line. For the experimental convenience, microstrip line was employed as a power-ground line and input impedance and radiation of the line with the decoupling capacitors were calculated and measured. From the experimental results, though the impedance of decoupling capacitor with resistor is much higher than that of decoupling capacitor without resistor the radiation profile is almost same and peaks at resonant frequencies are dumped.