A New Linear Micro strip Patch Antenna Array

In this paper the design of inset feed Linear Micro strip patch antenna array has been proposed. It has been observed for a printed antenna array at frequencies of 2.9GHz and 7.7GHz. The Ansoft HFSS 13.0 software is used to simulate the antenna array. The dimension of each patch antenna in the array of four antennas is 25mm×18mm. The characteristics of the antenna array are determined in terms of Return loss, VSWR and gain. The array produces a return loss of 15.70dB at 2.9GHz and a return loss of 18.92dB at 7.7GHz. The VSWR values are 1.39:1 at 2.9GHz & 1.25:1 at 7.7GHz. The overall obtained gain is around 3.8 dB. Keywords—Gain, Micro strip patch, Return loss, VSWR and Inset feed. I.INTRODUCTION In many of the modern applications like wireless communication system requires simple structure antennas with a low profile, light weight and high gain to give better reliability, mobility, and high efficiency characteristics [1, 2] Micro strip antennas are easy to fabricate and are light weight with low profile. The applications are limited by poor efficiency, gain and narrow impedance bandwidth [3]. these drawbacks occur due to the impedance mismatch and to overcome this feed should be given where the resonant resistance and feed-line resistance are equal. Micro strip structure design requires understanding of the mathematical relations and also its applications [3]. In many applications, in order to provide high efficiency the micro strip patch antenna is fed using either coaxial probe feed or insert micro strip line as both are direct contact methods [4]. If we consider a single antenna, it resembles a cavity backed antenna as proposed by saloon [5] which is nothing but a suspended antenna which is designed to get high bandwidth and gain. This proposed antenna suffers from impedance mismatch which can be overcome by the inset feed. The Inset-fed Micro strip antenna with a planar feed configuration provides a method for impedance control that is required. This antenna provides the advantages of printed circuit technology. These advantages of Micro strip antennas make them popular in many wireless communication applications such as satellite communication, radar, medical applications, etc. [6] Here we use an array of antennas instead of a single antenna in order to improve its gain. An array is one in which the current is spitted up in between the antennas in the array and here we use an array of four antennas. In many of the cases like high gain arrays we use an inset feed which provides high efficiency where the input impedance is determined by the inset length. In this paper we propose a method for designing the inset feed section of the array to reduce the mismatch between the patch and feed network. The input impedance of the inset feed micro strip patch antenna mainly depends on the inset distance ̳A‘ and to some extent on the inset width [7] and in some cases the inset gap is taken the same width as the feed line [8]. II. ANTENNA DESIGN The patch antenna was designed depending on the basics of the transmission line model (TLM). The width of the patch can be calculated by the formula √ A New Linear Micro strip Patch Antenna Array 2702 International Journal of Engineering Research & Technology (IJERT) Vol. 2 Issue 10, October 2013 IJ E R T IJ E R T ISSN: 2278-0181 www.ijert. org IJERTV2IS100668 Where ̳ ‘ is the substrate dielectric constant, ̳W‘ is the width of the patch and ̳h‘ is the height of the substrate. An effective dielectric constant εreff is used which is defined as the dielectric constant of the uniform dielectric material and given by,