Compact 1 × 4 patch antenna array by means of EBG structures with enhanced bandwidth

ABSTRACT In this paper, a novel design of compact 1 × 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 Ω 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 Ω slotline transitions, dual wideband patch array is obtained. The proposed 1 × 4 patch array with CMT‐EBG includes two bands with the measured ranges (S11≤−10 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 × 4 array with EBG is also introduced to describe the process of its bandwidth enhancement. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2983–2989, 2016