Biconical Patch Antenna with Inscribed Fractal Sierpinsky Gasket for Low Range Wireless Communication Systems GENARO HERNANDEZ-VALDEZ, MARIO REYES-AYALA, SAMUEL I. VALDES-CRUZ, IVAN R. GONZALEZ-RANGEL, J. R. MIRANDA-TELLO, EDGAR A. ANDRADE-GONZALEZ Electronics Department Universidad Autónoma Metropolitan Av. San Pablo 180, Reynosa Tamaulipas, Azcapotzalco 02200, Mexico City MEXICO ghv@correo.azc.uam.mx http://www.uam.mx Abstract: - In this paper, a biconical patch antenna with inscribed third iteration fractal Sierpinsky gasket is designed and optimized for operating at unlicensed ISM frequency bands. A circular split ring resonator (CSRR) is used as a defected ground-plane structure for improving antenna matching. The initial design step of the proposed antenna is based on the design methodology of multi-resonant Sierpinsky fractal patch antennas with inscribed triangular fractal geometry. Building on this, a simulation tool for high frequency electromagnetic structures is employed to optimize antenna performance. The experimental prototype is built and characterized using an antenna pattern measurement equipment and a network analyzer. Experimental results shown that the built antenna presents return losses of -23 dB, coupling bandwidth percentage of 10 %, antenna gain of 6.8 dBi, and VSWR of 1.14 at the 2.4 GHz resonant frequency. The corresponding values at the 5.9 GHz resonant frequency are -33 dB, 9 %, 8.7 dBi, and 1.043, respectively. These results show that the proposed antenna presents suitable characteristics for low range wireless communications such as WiFi (wireless LAN), Bluetooth, and ZigBee technologies. Key-Words: - Patch Biconical Antenna, Sierpinsky Gasket, Fractal Geometry, Multiband Antennas. 1 Introduction Due to the increasing demand of wireless communication applications requiring high data rates, five generations (5G) technologies will be introduced in the near future developed to achieve superior performance over nowadays wireless and mobile communication systems [1]. In these scenarios, the development of high performance antennas will be of paramount importance. In this research direction, patch antennas have been developed to achieve requirements such as miniaturization, low profile, compatibility with electronic circuits, easy design methodologies, among others [1]-[2]. On the other hand, multi-band antennas are required in cognitive radio networks; also wideband antennas are required in ultra wideband systems. To solve this requirements, a diversity of fractal geometries (such as the Sierpinsky gasket, Hilbert curve, snowshape of Knoch, hexagonal, “E”, “T” and “U” shapes, among others) has been combined with the patch technologies to improve antenna performance in terms of multiband and wideband characteristics [3]-[13]. Also, several fractal patch antennas with multiband behavior have been proposed for wireless local area network (WLAN) applications. Among these antennas, we found the biconical (also known as bowtie) patch one. The multi-band behavior of the biconcal antenna has been improved by the use of the Sierpinsky gasket fractal geometry [9]-[11]. On the other hand the coupling efficiency of the bowtie antenna has been improved by the use of ground-plane defects [11]-[16]. In this paper, we propose the use of both patch and ground-plane defects in the structure of the biconical patch antenna to improve both multi-band behavior and return losses. In particular, patch defects are introduced by means of the Sierpinsky gasket geometry [6]-[8], while ground-plane defects are incorporated by means of the circular split ring resonator (CSRR) technique [14]-[16]. The rest of the paper is organized as follows. In Section 2, the methodology for the initial WSEAS TRANSACTIONS on COMMUNICATIONS Genaro Hernandez-Valdez, Mario Reyes-Ayala, Samuel I. Valdes-Cruz, Ivan R. Gonzalez-Rangel, J. R. Miranda-Tello, Edgar A. Andrade-Gonzalez E-ISSN: 2224-2864 35 Volume 17, 2018