International Journal of Modern Engineering Research (IJMER) www.ijmer.com Vol.2, Issue.3, May-June 2012 pp-811-815 ISSN: 2249-6645 www.ijmer.com 811 | Page Govardhani.Immadi 1 , M.Venkata Narayana 2 M.S.R.S Tejaswi 3 , N.Anil Babu 3 , V.Vamsi Krishna 3 , M. Sagar Babu 3 , N.Ravi Teja 3 1. Woman Scientist, Department of ECE, K L University, India 2. Assoc. professor, Department of ECE, K L University, India 3. Project students, Department of ECE, K L University, India ABSTRACT In this paper a novel design of small sized, low profile coaxial fed microstrip patch antenna is proposed for terrestrial DTV signal reception applications in the UHF band frequency range of 540-890MHz. Designed model was spiral slot microstrip patch antenna using shorting plates for size reduction. Different parameters like return loss, VSWR, gain along θ, Ø directions, radiation pattern in 2D & 3D , axial ratio, E & H field distributions, current distributions are simulated using HFSS 13.0. The measured parameters satisfy required limits hence making the proposed antenna suitable for DTV reception applications in the UHF band. Keywords- coaxial fed, DTV, FR4, UHF 1. INTRODUCTION Conventionally, Yagi antenna has been used together with a TV receiver system to capture the electromagnetic wave energy broadcasted from a TV broadcasting station. This antenna has become more popular among the people living both in urban or rural. The popularity of Yagi antenna is not only due to the excellent characteristics such as gain and directivity but also other benefits like easiness in the process of design/ construction/fabrication, installation, maintenance and inexpensive [5]. Apart from these advantages and ease of practical application, this type of antenna has some limitations in terms of the flexibility of use. If there are 2 to 3 sets of TV receiver device in one house, it will take more towers to install them. The negative impact raised in the environmental issue and the crowded arrangement of the antenna installation where it occupies large space. As the position of the TV receiver changed in the building the configuration of cable connection must be reinstalled. Also the gain insufficiency for remote applications, appearance of grating lobes makes the Yagi disadvantageous. Nowadays, there is a Yagi antenna for indoor applications widely available in the market place which can be connected to the TV receiver to replace the outdoor one. But in terms of size and model it would require the proper arrangement of the room/space so that the quality of signal reception cannot be interfered due to the mobility of moving objects/people and the influence of interference from electronic devices in the vicinity[3]. For applications in other communication systems to access various DVB services such as from mobile phones, laptops/notebooks and PDAs the newest research and innovations concerning the construction of the internal antenna are very important to conduct. The antenna design must fits perfectly integrated inside a communication device. Some research activities to discover a new internal antenna have been published [6-10]. The results of investigations on a number of the internal antenna designed to be integrated with digital TV receiver has been proposed[4]. The choice of monoplole[16],printed monopole[11-12],dipole antennas[13- 14] improve the bandwidth to a greater extent. But, monopole antennas are of large size and difficult to build and integrate. Printed monopole antennas also have numerous advantages like low profile, small size, easy integration but has disadvantage of low broad impedance bandwidth and low omnidirectional radiation pattern. The dipole antennas have large input impedance. So, an impedance matching transformer or balun coil at feed point is required which increases the size of antenna[2][16-20]. Due to the numerous advantages of patch antenna[2][17-20] and in view of various techniques to improve the performance of microstrip patch antenna mentioned in [2], a C-slot to enhance the bandwidth of proposed antenna is proposed[1]. To reduce the dimensions of this antenna shorting plates are placed and slots are increased for the antenna to operate at multiple frequencies thereby receiving multiple band of channels. In this paper, a compact size patch antenna is proposed with dielectric substrate as FR4 with εr=4.4 and dimensions are base on resonant frequency. Various attempts are made to adjust the dimensions of the patch to impove the parameters like return loss, VSWR, gain along θ, Ø directions, radiation pattern in 2-D and 3-D, axial ratio, E and H Field Distributions, Current Distributions using HFSS 13.0 which is a high performance full wave EM field simulator for arbitarary 3D volumetric passive device modelling that takes advantage of the familiar Microsoft Windows graphical user interface. It integrates simulation, visualization, solid modelling, and automation in an easy to learn environment where solutions to your 3D EM problems are quickly and accurate obtained. Ansoft HFSS employs the Finite Element Method (FEM), adaptive meshing, and brilliant graphics to give you unparalleled performance and insight to all of the 3D EM problems. Design of Coaxial fed Spiral-Slot Microstrip Patch Antenna for DTV Reception with Shorting Plates