Multiband Array Antenna towards Microstrip Patch antenna using Resonant Frequency for s band Application Nivedita Mishra Department of Electronics and communication Engineering Integral university, Lucknow nivimini01@gmail.com Dr Saima Beg Department of Electronics and communication Engineering Integral university, Lucknow saimabeg@iul.ac.in Preeti Singh Department of Electronics and communication Engineering UIET, CSJMU, Kanpur preeti.12kec@gmail.com Abstract— In today's world, requirement for lower-weight, low-cost, low-profile, and effective-use transmitters is growing by the day. For addressing these parameters in a variety of applications, microstrip patch antennas are more popular than other antennas. The main issue with these types of microstirp patch antennas is that they have a high return loss, VSWR, and bandwidth, but these issues can be rectified utilising a design technique. The method of design was to use mirror image layouts, which was a simple and easy way to improve performance. The efficiency of a simple patch cannot be influenced by any single structure that lacks a mirror reflection. In this study, the two +- shaped constructions are used, and the results are in good agreement. In today's world, these antennas have a variety of uses, including WLAN and s band applications. In future, various frameworks will be used to improve the results that have been produced thus far. Keywords— Bandwidth, Rectangular Microstrip patch Antenna(RMPA), Return Loss, Ground Plane, FR4 ,Resonant frequency. 1.Introduction In recent years, advancements in communications networks have necessitated the creation of low-cost, light-weight, low-profile antennas capable of delivering great performance across a broad frequency band. The goal of prospective personal communication device development will be to allow image, voice, and data communications at any moment and from everywhere on the planet. To adequately cover the available operating bands, new communication endpoint transmitters must meet criteria of multi-band or wideband activities. The manufactured transmitter performance was measured and matched to modeling findings. In addition, we've discussed how to use FR4 for a variety of objectives, including antenna area diminution and other mode alteration-related tasks. The efficiency of rectangular patch transmitter built on FR4 substrate has been compared to that of similar antenna built on a standard FR4 substrate. Microstrip patch antennas are extensively employed in wireless devices in modern wireless communication networks. As a result, transmitter shrinking has become a critical challenge in lowering the overall size of the communication system. Microstrip patch antennas are extensively employed in wireless devices in contemporary wireless communication networks. The suggested Antenna's advantages, such as light weight, lower profile, lower cost, easy integration with innovation and engineering, and considerably simple production, are driving demand in commercial and military wireless systems. All of these antennas may be manufactured with the help of IE3D simulation software and have extremely crisp features. Because of its lower profile and tiny size, suggested RMPA can be employed in a wide range of wireless communication technologies. Due to its lower profile and smaller weight, microstrip antennas are widely utilized in radio communication technologies A Microstrip, Patch transmitter in its most basic form, contains a transmitting patch on one end of dielectric substrate with a grounding plane on other. The patch is typically made of conductive metals like gold or copper and may be manufactured into any shape. The transmitting patch and feed lines is normally photo etched on Journal of University of Shanghai for Science and Technology ISSN: 1007-6735 Volume 23, Issue 7, July - 2021 Page -995