In this paper, a novel design of compact 1 3 4 patch antenna array using electromagnetic band gap (EBG) for wideband operation is introduced. Three unequal arms fed by CPW-to-slotline through a coupling system of 100 X T-shaped slotline transitions are utilized for broadening the impedance bandwidth with multiple resonances. By adding two conventional mushroom-type EBG (CMT-EBG) structures on both sides of 100 X slotline transitions, dual wideband patch array is obtained. The proposed 1 3 4 patch array with CMTEBG includes two bands with the measured ranges (S11210 dB) of 6.71–6.97 GHz and 8.60–11.51 GHz. Moreover, more size reduction is achieved by using an edge-shorted mushroom-type EBG (ESM-EBG) for the proposed array. This design with the ESM-EBG indicates almost 37% size reduction compared with the proposed array without EBG. In this paper, an equivalent circuit model of the proposed 1 3 4 array with EBG is also introduced to describe the process of its bandwidth enhancement.
