Design of Compact Printed Wideband Antenna for 5.2/5.8 GHz WLAN and 3.5/5.5 GHz WiMAX Wireless USB Dongle Application Hrishikesh Narayan Tripathi School of Electronics and Commn. Engg. Shri Mata Vaishno Devi University Katra, India, 182320 hrishikesh.tripathi7@gmail.com Kumud Ranjan Jha School of Electronics and Commn. Engg. Shri Mata Vaishno Devi University Katra, India, 182320 jhakr@rediffmail.com Abstract— In This manuscript, a small reduced ground plane printed antenna to be used in WLAN/WiMax is analyzed. The reduced ground plane antenna is designed on the FR-4 substrate whose length width and thickness are 30 mm, 15 mm and 0.8 mm, respectively. The length and width of the antenna are 10 mm and 15 mm respectively. The compact antenna offers a wide bandwidth and may be used in WiMAX and WLAN Dongle applications. Keywords— Small antennas, Notch, slot, ultra wideband (UWB), Compact printed antenna, multiband. I. INTRODUCTION Wireless devices and systems based on ultra wideband (UWB) radio technology with the frequency allocation of 3.1–10.6 GHz, support low output power and high data rate (110–200 Mb/s) over the short ranges (4–10 m). It also supports an intelligent application which provides accurate location- tracking capabilities over the increased link range, i.e., over 30 m [1]. The design of UWB antennas is one of the major factors affecting the progress of UWB technology. As a result, researchers have shown the interest in the study of this kind of the antenna [2]. The compactness is the primary requirement of this kind of the antenna as UWB antennas need to be fitted in the USB Dongle. In the past, a few UWB USB antennas have been reported. These include the meandered strip type [3], the coplanar waveguide (CPW)-fed monopole types [4,5], the microstrip-fed patch types [6,7]etc. However, most of them have either a complex structure or a large size. In this paper, a novel compact printed antenna covering 5.2/5.8 GHz WLAN, 3.5/5.5 GHz WiMAX is proposed. II. ANTENNA CONFIGURATION The geometry of the synthesized UWB microstrip- fed patch antenna is shown in Fig. 1 which evolves from a rectangular patch. The patch is realized on the top of the 0.8 mm thick FR Substrate ( 018 . 0 tan , 4 . 4 = δ = ε r ) where the substrate length ( L sub ) and width (W sub ) are 30 mm and 15 mm, respectively. The ground plae is placed at the opposite face of the patch whose length (L g ) is 18. 4 mm and the width is same as of the substrate material. The antenna parameters are shown in Table 1. The length and width of the patch is indicated by (Lp) and (Wsub). A 50- microstrip line of width W1 and length L1 is used to feed the antenna. (a) (b) Fig.1. (a) Layout The front view of the primitive antenna, (b) the side view of the proposed antenna. TABLE 1. GEOMETRICAL PARAMETERS OF THE ANTENNA III. PARAMETRIC STUDY TO IMPROVE THE BANDWIDTH To improve the matching condition and to increase the bandwidth, two triangular notches consisting of sides P1, P2 and P3 are created in the patch. The effect of the variation of P3 on the impedance bandwidth is shown in Fig. 2 (a) where P1=4mm. When P3 is varied from 2 to 6 mm, the |S 11 | parameter improves due to reduction in the overall quality factor. In second case, P3 is fixed to 4.2 mm and P1 is varied from 2 to 7 mm as shown in Fig. 2 (b). As expected the similar change in the scattering parameter is noticed and this way these two parameters can be optimized to improve the -10 dB as well as -15 dB impedance bandwidth. However, the third parameter ‘g’ shows the different behavior. With the increase in ‘g’, the scattering parameter in upper pass band improves