An improved miniaturized three-layer embedded electromagnetic bandgap structure

A miniaturized planar electromagnetic bandgap (EBG) structure with embedded meander line as bridge is proposed. The dimensions of the unit cell of the proposed EBG structure are 15 mm × 15 mm × 0.36 mm. Simulation and measurement of the noise transmission coefficient (S₂₁) have been performed for the structure. And good agreement can be seen. According to the measured results, the -30 dB noise suppression bandwidth ranges from 0.97 to 21.54 GHz, which cover almost the whole noise band in ultrawideband applications. However, difficulties arise when the EBG structure is put in a stripline-like environment; the embedded EBG structure loses the noise filtering function. This communication proposed a solution by interconnecting the top and bottom planes of the embedded EBG structure with vias. The bandwidth and depth of noise suppression of the embedded EBG structure can be improved by the location and number of the vias. Simulation and measurement results demonstrate that the proposed embedded EBG structure can be effective for the desired noise isolation, which proved the correctness of the design of the three-layer embedded EBG structure.