Structural modification of mushroom EBG for wider band gap, reduced design complexity and compactness

An attempt to reduce the size of printed patch antenna and arrays severely degrades antenna performance, and it results in increased side lobe level. Electromagnetic band gap (EBG) structure is used to suppress side lobe levels and is utilized to enhance such antenna performance, but it significantly enlarges overall antenna size. This paper proposes a modified EBG structure with wider band gap and compact size. The conventional mushroom EBG geometry is complex due to presence of many vias. The proposed structure is simple to fabricate due to less EBG patches and vias. Also substrate size is significantly reduced by 89.24% with even much better band-gap. Proposed EBG structure is scaled and tested for X-band applications. It has been observed that the new structure has 31.75% wider band gap as compared to the reference structure. The integration of proposed EBG with microstrip antenna array has shown significant improvement in antenna parameters like gain, directivity, side lobe level, and radiation efficiency.