Indonesian Journal of Electrical Engineering and Computer Science Vol. 11, No. 2, August 2018, pp. 429~436 ISSN: 2502-4752, DOI: 10.11591/ijeecs.v11.i2.pp429-436  429 Journal homepage: http://iaescore.com/journals/index.php/ijeecs Novel UWB Microstrip Antenna Structures with Defected Ground Structure S. Elajoumi 1 , A. Tajmouati 2 , J.Zbitou 3 , A. Errkik 4 , L. El Abdellaoui 5 A.M.Sanchez 6 1,2,3,4 Laboratory LMEET FST of Settat, University Hassan 1 st , Morocco 5,6 DICOM Laboratory, Cantabria University, Santander, Spain Article Info ABSTRACT Article history: Received Apr 1, 2018 Revised Jun 20, 2018 Accepted Jul 7, 2018 This paper presents the design of new compact printed antennas for Ultra Wide Band applications, fed with a microstrip-line. The proposed designs consist of a patch antenna with defected ground, which are fed by 50Ω microstrip transmission line. The frequency range is 3.1-10.6 GHz which is the Federal Communication Commission (FCC) band of UWB. The proposed antennas are easy for integration with microwave circuits. They are validated into simulation by using two electromagnetic solvers CST-MW and Ansoft HFSS. The simulated input impedance bandwidth ranging 3GHz to more than 14 GHz is obtained with return loss less -10dB, and exhibits good UWB characteristics. The measured parameters are good agreement with the simulation. Therefore these antennas offer excellent performance for UWB system. Keywords: WideBand (UWB) FCC Defected ground CST microwave studio Ansoft HFSS Copyright © 2018 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: S. Elajoumi, Laboratory LMEET FST of Settat, University Hassan 1 st , Morocco. Email: saida.elajoumi@gmail.com 1. INTRODUCTION Ultra-wide band (UWB) often considered as a recent technology in wireless communication UWB. In other word UWB transmission occupies an extremely wide bandwidth exceeding the minimum of 500 MHz or at least 20% of center frequency. UWB technology can be the most suitable technologies to immunity to patch interference and to revolutionize high data rate transmission. In February 2002 the Federal Communication Commission (FCC) officially released the regulation for UWB technology, with a given spectral mask for both indoor and outdoor applications in USA [1]. In accordance with the FCC regulations, the frequency band from 3.1GHz to 10.6 GHz can be used for short-range and high speed wireless communications systems. The FCC power spectral density (PSD) emission limit is -41.3dBm/MHz, so that power of UWB signal is considered as the noise for other wireless technologies. Therefore UWB communication technology became popular and extremely useful, due to various satisfying factures such as high data rate, high precision ranging, low cost and without inducing strong interference to wireless systems. UWB is regarded as very promising for vast array new applications in which it can used, for public safety, business and consumers in variety of application in wireless communication, sensor networking, radar, imaging and positioning systems. To satisfy such requirements, many research efforts around the world have been focused on the design of antenna operated in different frequencies for various wireless transmission functions, and operation bands. Several researchers exploring RF design of UWB applications [2-4]. The UWB antenna should have extremely wide impedance bandwidth, compact size, effective in transmitting, nearly omnidirectional radiation pattern and easy fabrication on printed circuit boards (PCBs). Finally these researches give a huge boost to the design of microstrip antennas for UWB applications. The main advantages of microstrip patches