Dual-band microstrip antenna array with a combination of mushroom, modified Minkowski and Sierpinski electromagnetic band gap structures

A novel concept involving a single-port dual-band microstrip antenna array (DbMSAA) incorporated with electromagnetic band gap (EBG) structures is reported. Three types of EBG structures are used in the designs, which include the mushroom EBG, a modified Minkowski EBG and Sierpinski EBG structures. These EBG structures operate like a band rejecter, separating the branch of feed lines feeding two different groups of arrays of patch antennas, thus making them operate individually at their particular frequencies, simultaneously. Initially, with the new DbMSAA model configuration, the possibilities of having uniform and controlled radiation patterns are quite complicated to achieve because of the single-port feeding technique used and developments of grating lobes at the higher band frequency. By incorporating the EBG structures, these problems are solved. The antenna´s performance improves with the radiation patterns of the dual-band antenna at both frequencies becoming more symmetrical and having increased gain.