Bandwidth enhancement of microstrip patch antennas using Electromagnetic Bandgap (EBG) structures with square and circular unit cells

Abstract

Antenna is one of the important elements in the RF system for receiving or transmitting the radio wave signals from and into the air as a medium. The microstrip patch antenna is the most preferred for low cost and compact design. In this paper, a microstrip patch antenna mounted over a high impedance electromagnetic bandgap (EBG) substrate using square and circular shaped unit cells is proposed. A wide operating bandwidth of a microstrip patch antenna can be obtained by arranging EBG patches in two rows. The proposed antenna design is simulated on electromagnetic (EM) simulation software using FR-4 substrate with dielectric constant of 4.54 and thickness of 1.60mm. This antenna has a compact structure with a total size of 60x60mm square. The bandwidth of microstrip patch antenna is enhanced by replacing a conducting ground plane by a high impedance EBG layer. It is also found that the circular shaped EBG cells exhibits higher bandwidth than that of the square shaped EBG cells having same area. A novel design of this microstrip patch antenna is integrated with square and circular unit cells which exhibits significantly wider bandwidth than the conventional one. The bandwidth of microstrip patch antenna using square shaped unit cells is found to be 11.40% and that of circular shaped unit cells is 16.65% which is much higher than that of conventional antenna without EBG substrate whose bandwidth is calculated to be 4.28%. The simulated results show the good agreement with the proposed scheme.