http://www.iaeme.com/IJECET/index.asp 14 editor@iaeme.com International Journal of Electronics and Communication Engineering and Technology (IJECET) Volume 7, Issue 6, November-December 2016, pp. 14–21, Article ID: IJECET_07_06_002 Available online at http://www.iaeme.com/IJECET/issues.asp?JType=IJECET&VType=7&IType=6 Journal Impact Factor (2016): 8.2691 (Calculated by GISI) www.jifactor.com ISSN Print: 0976-6464 and ISSN Online: 0976-6472 © IAEME Publication DESIGN OF ANTIPODAL VIVALDI ANTENNA WITH PERIODIC CROSS SLOTS FOR IMPROVING GAIN PERFORMANCE L. Sree Lakshmi Sowjanya, G. Veerendra Nath Department of ECE, VR Siddhartha Engineering College, Vijayawada, A.P., India ABSTRACT In this paper a printed antipodal Vivaldi antenna with pairs of cross slots is proposed to improve the antenna gain by reducing the side lobe levels of the radiation pattern. This is a new approach for applications like radar and ultra-wide band (UWB). While designing the proposed antenna with slots, initially an antipodal Vivaldi antenna is presented. Further proposed antenna designed by introducing periodic cross slots, which results in improvement in gain significantly along with increased directivity. To describe effectiveness of the proposed antenna the results are simulated and compared. Simulation results show that the proposed antenna has a return loss |S11| < -10 dB, with a range from 6 to 18 GHz with a compact size 60(L)×30(W)×1.6(h)mm3. Good unidirectional radiation characteristic also achieved with the proposed antenna. Key words: Tapered Slot Antenna (TSA), Ultra-Wide Band (UWB), Antipodal Vivaldi Antenna (AVA) and Periodic Cross Slots (PCS). Cite this Article: L. Sree Lakshmi Sowjanya and G. Veerendra Nath, Design of Antipodal Vivaldi Antenna with Periodic Cross Slots for Improving Gain Performance, International Journal of Electronics and Communication Engineering and Technology, 7(6), 2016, pp. 14–21. http://www.iaeme.com/IJECET/issues.asp?JType=IJECET&VType=7&IType=6 1. INTRODUCTION Wideband antennas are desired for different applications including satellite communications, microwave imaging systems, remote sensing systems, radars, electronic warfare, and telescopes. By using directional antennas, the co-channel interference and multipath effects of wireless communication systems can be reduced [2–4]. In recent years, the ultra-wideband technologies have received extensive attention. From antenna theory two types of antennas are used for this purpose. One is horn antennas but these are too bulky to use and to be integrated with the rest and result high fabrication costs. So there is need of broadband antennas with compact sizes. Some of wide band antennas have attained a lot of importance because of their advantages like compact structure, small size and ease of integration. Gibson invented Vivaldi antenna also called Tapered slot antenna [1], which comes under this and has been widely used in antenna research [2], [3] and in phased arrays for wide band systems [5, 6]. Because of their end fire directional patterns and good gain over a very broad operating frequency range these are good for multifunction communication applications. In Vivaldi antennas there are mainly 3 types. First one