Miniaturization and Gain Enhancement of Microstrip Patch Antenna Using Defected Ground with EBG Dhawan Singh 1,2 , Aditi Thakur 2 , and Viranjay M. Srivastava 1 1 Department of Electronic Engineering, Howard College, University of KwaZulu-Natal, Durban - 4041, South Africa 2 Department of Electronics and Communication, Eternal University, Baru Sahib, Sirmour-173101, India Email: dhawan_deor@ieee.org; aadditisharma@gmail.com; viranjay@ieee.org Abstract —In this research work, we have proposed an inset feed rectangular microstrip patch antenna operating at 2.45 GHz in the Industrial, Scientific and Medical (ISM) band for wireless communication. This conventional design of antenna has been modified with defected ground (DG) plane. When this is optimized back to 2.45 GHz, a miniaturization of 37.9 % of patch size has been achieved along with the enhancement in radiation performance. This design is then modified and loaded with mushroom-type Electronic Band-Gap (EBG) structure on the top of dielectric FR-4 substrates. This creates a band-gap region that suppresses the surface waves considerably, thus improves the overall performance and functionality of the proposed antenna. Radiation characteristics such as S-parameters, directivity, gain, efficiency, bandwidth, VSWR and Z 11 of microstrip antenna have been performed and compared. The simulated results show that the antenna gain has been increased throughout the entire bandgap of EBG operating in 2.25 to 4.25 GHz. Moreover, rest of radiation performances remain highly preserved. Index Terms—Dispersion, Electronic band-gap (EBG), Frequency selective surface (FSS), Metamaterial absorber (MMA), Radar Cross Section (RCS) I. INTRODUCTION The recent technological advancement and the latest research in metamaterials have pioneered the door to tremendous innovative antenna applications. A novel metamaterial structure efficiently manipulates the reflection and transmission of the impinging electromagnetic (EM) wave. By changing the physical and geometrical construction of metamaterial, one can demonstrate a pass-band and stop-band filter behavior. Some worthy of notice amelioration that can be impute to periodic metamaterial structures in antenna designing covers surface waves suppression [1]-[3], antenna size reduction [4], [5], enhancement of antenna efficiency [6], [7], mutual coupling reduction among exiting elements in antenna arrays [8], [9] and enhancement of stealth capability of antenna by lowering of radar cross section (RCS) [10]-[12]. A metamaterial absorber (MMA) periodic structure has been utilized efficiently to enhance the in-band stealth capability of the antenna by reducing its RCS [13]-[16]. Manuscript received February 15, 2018; revised November 21, 2018. Corresponding author email: dhawan_deor@ieee.org. doi:10.12720/jcm.13.12.730-736 (a) (b) Fig. 1. The geometry of EBG unit cell. (a) perspective view and (b) Dispersion curve with dimensions: S= 16 mm, g= 1 mm, h=1.5 mm, t= 0.035mm and via= 0.5 mm. On the other hand, it marginally degrades and affects the antenna radiation performance [17-18]. Similarly, a frequency selective surface (FSS) can act as a band-pass or band-stop filter in antenna radomes, artificial magnetic conductor (AMC) and find applications in lowering antenna’s RCS [19]-[22]. However, it also deteriorates antenna radiation performance [23]. Contrary to this defected ground structure (DGS) has been widely used for different applications such as radiation properties enhancement [24], bandwidth [25], mutual coupling reduction in antenna arrays [26] and antenna size reduction [27]. The DG plane is realized by etching off a shape in the ground plane. Depending on the geometry and dimensions of the defective shape, the impedance and surface current distribution get perturbed and this further Journal of Communications Vol. 13, No. 12, December 2018 ©2018 Journal of Communications 730