Compact ( $\lambda /45$ -Sized) Electromagnetic Bandgap Structures With Stacked Open-Circuit Lines

This letter introduces double layer layouts of open-circuit lines into the electromagnetic bandgap (EBG) structures to enable changing the shunt circuit of the parallel plate waveguide to inductance in compact spaces. That is, compact EBG structures were achieved. The EBG structures, fabricated using standard fabrication processes and using a low-cost substrate (flame retardant type 4), enable a 1-mm-order size for a 2.4-GHz BG. The size is less than 1/10 of the conventional mushroom structures and corresponds to 1/45 of a substrate wavelength. This compact as well as low-cost EBG structure is promising for noise suppression applications of power distribution networks, especially for wireless products with high-density circuit boards.