Focus Research



Reducing the power distribution networks (PDN) noise has been becoming one of the major concerns for power integrity design for the high-speed circuits and mixed signal systems in recently few years. The challenge will be expected to increase in next decade as the electronic systems are driven in the direction of higher digital speed, higher integration with RF circuits, and higher throughput of data communication.

Applying electromagnetic bandgap structure (EBG) on the PDN has been shown effective for power noise suppression. We are the pioneer group to develop a new low-period coplanar electromagnetic bandgap (LPC-EBG) structure on the planar PDN. Keeping solid for the ground plane and designing LPC-EBG pattern on the power plane, the proposed structure omni-directionally behaves highly efficient suppression of power noise (over 50dB) within broadband frequency range (over 4GHz) [1]. Recently, two main research efforts are emphasized for the EBG structures applied in the PDN noise suppression. One is stopband bandwidth enhancement because of switching noise from digital circuits covering wide frequency band. The other is the miniaturization techniques due to the trend of system on package.

A photonic crystal power layer (PCPL), that periodically embeds high-DK rods between power and ground planes, has been demonstrated good noise suppression performance with size miniaturization. This approach keeps power and ground planes in continuous, and will improve both the power and signal integrity behavior [2]. The stopband can be enhanced by cascading two different configurations of PCPL that can cover different stopband range [3]. High fabrication and material cost are the challenges of this technique development. A ground surface perturbation lattice (GSPL) embedded between power and ground planes has been proposed with good noise isolation performance and also enhance the stopband by combining the coplanar L-bridged EBG power plane [4]. It is low cost without needing high-DK material. To our best knowledge, this idea has been demonstrated with widest stopband in terms of fractional bandwidth and very small unit-cell size compared to all published literatures.

  • [1] T.-L. Wu, Y.-H. Lin, T.-K. Wang, C.-C. Wang, and S.-T. Chen, “Electromagnetic bandgap power/ground planes for wideband suppression of ground bounce noise and radiated emission in high-speed circuits ,” IEEE Trans. Microw. Theory Tech., vol. 53, pp. 2935-2942, Sept. 2005.
  • [2] T.-L. Wu and S.-T. Chen, “A photonic crystal power/ground layer for eliminating simultaneously switching noise in high-speed circuit,” IEEE Trans. Microw. Theory Tech., vol. 54, no.8, pp. 3398-3406, Aug 2006.
  • [3] G.-Z. Wu, Y.-C. Chen, and T.-L. Wu, “Design and implementation of a novel hybrid photonic crystal power/bround layer for broadband power noise suppression,” IEEE Trans. Adv. Packag, May 2010.
  • [4] T.-K. Wang, C.-Y. Hsieh, H.-H. Chuang, and T.-L. Wu, “Design and modeling of a stopband-enhanced EBG structure using ground surface perturbation lattice for power/ ground noise suppression,” IEEE Trans. Microw. Theory Tech., vol. 57, pp. 2047-2054, Aug. 2009.