BROADBAND PATCH ANTENNAS BIO-INSPIRED IN THE ELLIPTICAL LEAF DEVELOPED WITH THE RIEMANN TRANSFORMATION FOR WLAN AND 5G APPLICATIONS *1 Tales A. C. de Barros, Paulo H. F. Silva, 1 Lamarks T. C. Cavalcanti, 2 Rodrigo C. F. da Silva, 2 Pedro Carlos de Assis Júnior, 3 Paulo F. Silva Junior, 3 Ewaldo E. C. Santana and 4 Elder Eldervitch Carneiro de Oliveira 1 Electrical Engineering Department, Federal Institute of Paraíba, João Pessoa – PB, Brasil 2 Phisics department, State University of Paraíba, Patos – PB, Brasil ³Graduate of Computer Engineeringand Systems, University State of Maranhão, São Luís – MA, Brasil 4 CCBSA Center, State University of Paraíba, João Pessoa – PB, Brasil ARTICLE INFO ABSTRACT This paper describes the development of broadband patch antennas using Riemann conformal transformation, on the square in the Argand-Gauss plane for wireless local area network (2.4 GHz and 5 GHz), and 5G band in 3.5 GHz. For this work was projected three antennas with the bio- inspired shape of the elliptical leaf(MPA R1, MPA R2, and MPA R3), using Riemann conformal transformation, for an increase of the bandwidth of the narrowband antenna (square patch antenna), fractional bandwidth of 3%, to broadband antennas, with fractional bandwidth greater than 5%. The project of the antennas was generated in MATLAB, simulated in the commercial software ANSYS, and built in low-cost material, fiberglass dielectric substrate. The measured results of the bio-inspired antennas patch antennas, with Riemann transformation, operation in the 2.4 GHz, 3.5 GHz and 5.8 GHz bands, with absolute bandwidth of 135 MHz (MPA R1), 220 MHz (MPA R2) and 440 MHz (MPA R3), fractal bandwidth of 5.6% (MPA R1), 220 MHz 6.3%(MPA R2) and 440 MHz 7.6%(MPA R3), the simulated maximum gain of 6.67 dBi (MPA R1), and a half-power beamwidth of 108 degrees (MPA R2). Copyright © 2020, Tales A. C. de Barros et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. INTRODUCTION The microstrip patch antennas (MPA) have characteristics of construction and operation that have been widely used in several civil and military applications (Kumar et al., 2003). In terms of operation, a conventional MPA antenna features a broadside radiation diagram with a good beam width, with a directional gain of around 6 dBi, with resonant properties of a narrowband antenna, with a percentage bandwidth between 1% and 3%, as (Balanis, 1997; Chen et al., 2005). These characteristics, reduced the gain and narrow bandwidth, often limit its applications in wireless systems and devices. However, the gain of an MPA antenna can be increased, for example, with the use of an arrangement of these antennasaccording to (Stuzman and Thiele, 2013). A review of techniques used to increase the bandwidth of MPA antennas can be found in (Ajay et al., 2012), and include: the modified shape patch, multiresonator technique, multilayered technique and stacked multilayered technique. Using these techniques, one can easily obtain percentage bandwidths above 10% for modified MPA antennas. The broadband technique, which modifies the patch format, was chosen for this study because it preserves most of the characteristics and advantages of a conventional MPA antenna. Some examples, which use this approach, have been reported in the literature and include the use of conventional patches (rectangular and circular) with slits (Jui-Han Lu, 2003; Deshmukh et al., 2013; Jeffrey et al., 2016; Ata et al., 2018). Generally, the shapes of the slots are letters, E, H and U according to the works (Aravindraj et al., 2017; Nitin et al., 2018) and (Ibrahim, 2019), these are the most used formats for improving the bandwidth, as well as for multiband applications. Antennas with U-shaped slots and fed ISSN: 2230-9926 International Journal of Development Research Vol. 10, Issue, 06, pp. 36776-36781, June, 2020 https://doi.org/10.37118/ijdr.19040.06.2020 Article History: Received xxxxxx, 2019 Received in revised form xxxxxxxx, 2019 Accepted xxxxxxxxx, 2019 Published online xxxxx, 2019 Available online at http://www.journalijdr.com Citation: Tales A. C. de Barros, Paulo H. F. Silva, Lamarks T. C. Cavalcanti, Rodrigo C. F. da Silva, Pedro Carlos de Assis Júnior et al. “Broadband patch antennas bio-inspired in the elliptical leaf developed with the riemann transformation for wlan and 5g applications”, International Journal of Development Research, 10, (06), 36776-36781. RESEARCH ARTICLE OPEN ACCESS Article History: Received 17 th March, 2020 Received in revised form 08 th April, 2020 Accepted 06 th May, 2020 Published online 29 th June, 2020 Key Words: CAD, Conformal mapping, Broadband antennas, Microstrip patch antennas, Wireless applications. *Corresponding author: Tales A. C. de Barros,