WIDEBAND SINGLE PATCH E-SHAPED COMPACT MICROSTRIP ANTENNA FOR HIGH SPEED WIRELESS LOCAL AREA NETWORKS G. Purnachandra Rao 1 , Kshitiz Agarwal 1 , M. V. Kartikeyan 1 , M.K.Thumm 2, 3 1 Department of Electronics & Computer Engineering Indian Institute of Technology, Roorkee 247 667, Uttranchal, India 2 Forschungszentrum Karlsruthe,IHM,Postfach 3640, D76021 Karlsrthue, Germany 3 Universitat Karlsruthe, IHE, D76128 Karlsruhe, Germany Abstract— This paper presents a single wideband E-shaped compact microstrip antenna for high speed WLANs operating in the 5 – 6 GHz range. By using only single patch a high impedance bandwidth is achieved. The simulated impedance bandwidth (VSWR<2) is 25.9%, and measured bandwidth is approximately equal to 24.85%. This prototype antenna has a gain of 8.5 dB. The back radiation lobe is also > 20 dB. This antenna is fed by a co-axial probe feeding. In this paper, the effects of different parameter of antenna are also studied. Index Terms — E-shape microstrip antenna, wide- band, wire less local area networks, dual parallel slots. I. INTRODUCTION ICROSTRIP patch antennas are widely used because of their several advantages [1] such as light weight, low volume, low fabrication cost, and capability of dual and triple frequency operations. However microstrip antennas suffer from a number of disadvantages. Narrow bandwidth is a serious limitation of these microstrip patch antennas. Different techniques are used to overcome this narrow bandwidth limitation. These techniques include increasing the thickness of the dielectric substrate, decreasing dielectric constant [1], and using parasitic patches [2]. These techniques have limitations like, excitation of surface waves and increase in antenna size. In wireless local area networks the antenna used is in PCMCIA format where a small size, low volume antenna is required. A rectangular patch with a U slot [3] embedded in it has been found to be a broadband antenna, and a single E-shaped patch with a height of 15 mm provide bandwidth up to 30%. In this paper, we present a wideband single E-shaped microstrip patch antenna with compact size that provides a bandwidth (VSWR < 2) approximately equal to 26%. This bandwidth covers both the high speed WLAN frequency bands (5.15 - 5.35 GHz and 5.725 - 5.80 GHz). It is to be noted that the antenna height is less than 5mm, so this antenna can be conveniently used for WLAN adapter cards in PCMCIA format. II.E-SHAPED MICROSTRIP PATCH ANTENNA When two parallel slots are incorporated into the rectangular microstrip patch antenna, it becomes an E-shaped microstrip patch antenna. The E-shaped microstrip patch antenna is simpler in construction. The geometry is shown in Fig.1. Figure 1: Geometry of the E-shaped microstrip patch antenna M