Ultrawideband Power-Noise Suppression Based on Lossy Capacitors With Low-Frequency Stopband Enhancement for Digital Systems

For most board-level digital systems, the power-noise interference covers a wide frequency range from near dc to several GHz. Current power-noise suppression methods can only selectively suppress low-frequency or high-frequency band-limited power noise. In this article, a novel plane pair embedded with lossy capacitors, each of which is formed by a conventional capacitor in series with a large resistor, is developed for ultrawideband power-noise suppression in high-speed digital systems, ranging from 10 kHz to several GHz. The noise suppression mechanism of the proposed structure is keeping the quality factor (
Q
-factor) of a plane pair to a very low level, say
Q
<4, by introducing lossy components to increase the equivalent conductivity of dielectric material between the plane pair. The stopband can be estimated by the
Q
-factor of a unit cell of the plane pair and adjusted by changing the physical parameters, such as series resistance, dielectric thickness, and period. The measured results show that the proposed plane pair embedded with lossy capacitors can achieve ultrawide −30-dB stopband, from 10 kHz to above 5 GHz.