Electrical and Electronic Engineering 2014, 4(2): 31-35 DOI: 10.5923/j.eee.20140402.02 Microstrip X-band Antenna with Improvement in Performance Using DGS Amit Singh Bhadouria * , Mithilesh Kumar Electronics Engg. Department, University College of Engineering, Rajasthan Technical University, Kota, 324005, India Abstract Simple and new microstrip patch (MSP) antenna for dual operation in X-band using Defective Ground Structure (DGS) is proposed here. DGS structure is used for improving the performance of microstrip patch antenna. By using four rectangular slots in patch we achieved two frequency bands one (9.24-9.68GHz) and other band (11.63-11.87GHz) both are in X-band. And for improving parameter like return loss, bandwidth, gain and directivity of MSP antenna one rectangular slot is cut in ground plane. The proposed antenna is compact in size with dimension 10 x 10 x 1 mm 3 with the ground plane. For designing and fabrication of this structure FR-4 substrate of thickness 1 mm with Dielectric constant 4.9 is used. The parameters of proposed antenna like return loss; Voltage Standing Wave Ratio (VSWR), radiation pattern; gain and directivity are simulated and analyzed using commercial computer simulation technology microwave studio (CST MWS). A good agreement between simulated and measured results is obtained. The designed antenna structure is very simple, compact and occupies less space all these qualities make this antenna suitable for practical applications. The main application of proposed antenna is to make compatible with radiolocation, radio navigation and fixed satellite applications in X-band (8-12GHz). Keywords DGS (Defective Ground Structure), MSP (Microstrip Patch), PBG (Photonic Band Gap), RADAR (Radio Detection and Ranging), SIW (Substrate Integrated Waveguide), VSWR (Voltage Standing Wave Ratio), X-Band 1. Introduction According to IEEE standards X-band ranges from 8.0 to 12.0 GHz which belongs to the microwave radio region of the electromagnetic spectrum. The X-band has wide applications in radar engineering. This band is widely used or short range tracking, missile guidance, marine, radar, and airbone intercept [1]. Basically it is used for RADAR communication and RADAR is an electromagnetic system for the detection and location of reflecting objects such as aircraft, ships, spacecraft, vehicles, people and the natural environment. Due to increase in demand of small antennas for RADAR communication there was huge increment in interest of research work on compact microstrip antenna [2-4]. We use microstrip antenna as ideal choice for RADAR applications because of various advantages such as the small size, light weight, thin profile, low cost and ease of fabrication [5]. MSP has lots of advantages but it also has few disadvantages like low gain, narrow band width and low efficiency. There are various methods to overcome from these disadvantages few of them are: * Corresponding author: aamit05singh@gmail.com (Amit Singh Bhadouria) Published online at http://journal.sapub.org/eee Copyright © 2014 Scientific & Academic Publishing. All Rights Reserved 1. Array configuration [3] 2. Multilayered structure [6] 3. Change in shape of patch and adding different shaped slots in patch in proper position [1], [7]. 4. Using low dielectric constant of substrate or increase the thickness of substrate [8]. 5. Proper feeding [4] and using metamaterial structure [9]. 6. And use different structure like photonic band gap (PBG)[10-11], substrate integrated waveguide (SIW) [2], and Defective Ground Structure (DGS) [12]. Due to increasing demand for microstrip patch (MSP) performance enhancement in MSP antenna we used DGS structure. Using DGS we can add an extra degree of freedom in microwave circuit design which opens the door to a wide range of applications [12]. DGS structure is realized by etching simple shape from the ground plane [13]. DGS disturbs the shield current distribution in the ground plane cause the defect in the ground. Due to this disturbance there will be changes in characteristics of a transmission line such as capacitance and inductance [12]. In this paper a new simple, compact MSP antenna is designed using defective ground structure for radiolocation, radionavigation and fixed satellite applications in X-band. Feeding is provided in this MSP antenna using microstrip line feeding technique. The performance of this antenna is optimized by