RESEARCH PAPER International Journal of Recent Trends in Engineering, Vol 1, No. 3, May 2009 42 Parametric Study of Printed Rectangular Monopole Antennas Jyoti Ranjan Panda, and Rakhesh Singh Kshetrimayum Department of Electronics and Communication Engineering, Indian Institute of Technology, Guwahati, India Email: { j.panda, krs }@iitg.ernet.in Abstract— This paper demonstrates an exhaustive parametric study of the printed rectangular monopole antenna (PRMA). The effect of varying the feed gap, plate length, plate width, feed-line width, substrate width and dielectric constant of the substrate is studied. It is found that the lower start frequency of the bandwidth (f L ) is almost unaffected from the variation of the feed-line width, dielectric constant of the substrate and the substrate width, but decreases linearly with the increase of the feed gap, plate length and width. Index Terms— Monopole antenna, Wide-band antenna, Printed circuit antenna I. INTRODUCTION Printed monopole antennas are widely used in the wideband communication systems. They are lightweight, low cost, compact, planar and easy to fabricate. They are popular planar antennas for wireless communications because they provide wide impedance bandwidth and omni directional radiation patterns. Printed planar monopole antennas are used extensively in GSM 1800, PCS 1900, IMT 2000, WLAN and UWB systems [1-5]. Many novel techniques were adopted in the past to achieve wide bandwidth of printed monopole antennas such as beveling and shorted posts [6]. Because of ease of the integration with integrated circuits, monopole antennas are fabricated on the printed circuit boards [7]. Parametric study of printed circular monopole antenna has been presented in [8], where the antenna performance is calculated by varying the size of substrate, feed length and ground plane. In this paper, the printed rectangular monopole antenna (PRMA) studied provides an impedance bandwidth from 1.58 GHz to 6.50 GHz, which can be used for GSM 1800, PCS 1900, IMT 2000, WLANs and UWB communication systems. Various design parameters of the PRMA are varied such as dielectric constant of the substrate, feed gap, feed-line width, plate length, plate width, and substrate and ground plane width. During these parametric studies, the behavior of the lower start frequency (f L ) of the bandwidth and higher end frequency (f H ) of the bandwidth is studied. II. ANTENNA GEOMETRY AND SIMULATION The geometry of the printed rectangular monopole antenna (PRMA) is shown in the Fig. 1 below. The rectangular printed monopole antenna is printed on one side of the FR4 substrate and the ground plane is located on the other side of the substrate. The dimensions of the FR4 substrate are w=50 mm and h=90 mm. The dimensions of the ground plane are w=50 mm and h g =50 mm. The dimensions of the rectangular printed patch are W=20 mm and L=30 mm. The antenna plate is fed by a microstrip line of characteristic impedance 50 Ω having the width w f =2.5 mm. The printed plate is located at a feed gap h f =2 mm from the ground plane. The FR4 substrate is H=1.59 mm thick and the metal thickness is 35 µm. Figure 1. Geometry of the printed rectangular monopole antenna (PRMA) A. Simulation results The PRMA was simulated using IE3D simulation software. Fig. 2 shows the simulated return loss from 1 GHz to 10 GHz. The lower start frequency of the bandwidth (f L ) is 1.58 GHz and higher end frequency of the bandwidth (f H ) is 6.50 GHz. Hence bandwidth of the antenna is 4.92GHz. Fig. 3 shows the simulated VSWR vs frequency plot. At the frequencies 1.56 GHz and 6.56 GHz, the value of VSWRs are 2 and from the frequency band 1.56 GHz to 6.56 GHz, the value of VSWR remains below 2 (VSWR < 2) yielding the impedance bandwidth of 5 GHz, which is depicted in the plot shown in the Fig. 3. © 2009 ACADEMY PUBLISHER