Sudhir Bhaskar & Sachin Kumar Gupta / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 1, Jan-Feb.2012, pp. 334-338 334 | P a g e Bandwidth Improvement of Microstrip Patch Antenna Using H- Shaped Patch Sudhir Bhaskar 1* & Sachin Kumar Gupta 2 1*, 2 Department of Electronics Engineering, Institute of Technology Banaras Hindu University Varanasi - 221 005 (Uttar Pradesh), India ABSTRACT Despite the many advantages of microstrip patch antennas, they do have some considerable drawbacks. One of the main limitations with patch antennas is their inherently narrowband performance due to its resonant nature. With bandwidth as low as a few percent; broadband applications using conventional patch designs are limited. So for the antenna miniaturization and bandwidth improvement H-shaped microstrip patch antenna used. In this paper, authors cover two aspects of microstrip antenna designs. The first is the analysis of single element narrowband rectangular microstrip antenna which operates at the central frequency of 3.3 GHz. The second aspect is the analysis and design of slot cut H-shaped microstrip antenna. The simulation process has been done through high frequency structure simulator (HFSS). The properties of antenna such as bandwidth, S parameter, VSWR has been investigated and compared between a single element rectangular and H-shaped microstrip antenna. Keywords –MSA, HFSS, Bandwidth I. INTRODUCTION The need for antennas to cover very wide bandwidth is of continuing importance, particularly in the field of electronic warfare and wideband radar and measuring system. Although microstrip patch antennas have many very desirable features, they generally suffer from limited bandwidth. So the most important disadvantage of microstrip resonator antenna is their narrow bandwidth. To overcome this problem without disturbing their principal advantage (such as simple printed circuit structure, planar profile, light weight and cheapness), a number of methods and structures have recently been investigated. In this regard we can mention multilayer structures [1], broad folded flat dipoles [2], curved line and spiral antennas [3], impedance matched resonator antennas [4], resonator antennas with capacitive coupled parasitic patch element [5], log periodic structures [6,7], modified shaped patch antenna (H-shaped [8]). In the present paper H- shaped microstrip patch antenna analyzed and compared with rectangular patch antenna. The H-shaped patch antenna here has a size about half of the rectangular patch antenna with larger bandwidth. The larger bandwidth is because of a reduction in the quality factor (Q) of the patch resonator, which is due to less energy being stored beneath the patch. Consider figure 1 below, which shows a rectangular microstrip patch antenna of length L, width W resting on a substrate of height h. The co-ordinate axis is selected such that the length is along the x direction, width is along the y direction and the height is along the z direction. Fig1. Microstrip patch antenna II. ANALYSIS METHOD FOR MICROSTRIP ANTENNA The preferred models for the analysis of microstrip patch antennas are the transmission line model, cavity model, and full wave model (which include primarily integral equations/Moment Method). The transmission line model is the simplest of all and it gives good physical insight. I. TRANSMISSION LINE MODEL This model represents the microstrip antenna by two slots of width W and height h, separated by a transmission line of length L. The microstrip is essentially a nonhomogeneous line of two dielectrics, typically the substrate and air. Fig.2 Electric field lines between patch and ground plane.