Progress In Electromagnetics Research B, Vol. 101, 63–84, 2023 Performance Improvement of Antenna Using Metasurface: An Overview Naresh C. Naik, Nibash K. Sahu * , Bijay K. Ekka, and Tapas K. Patra Abstract—This paper presents an in-depth review of the performance improvement of antennas using metasurface. Metasurface is a periodic arrangement of perfect electric conductors (PECs) on a metal- backed dielectric substrate that do not exist in nature and are able to manipulate the behavior of electromagnetic (EM) waves incident on it. The manipulations of EM waves improve the performances in terms of impedance bandwidth, gain, size, specific absorption rate (SAR), radar-cross-section (RCS), and polarization conversions. Consequently, numerous recent works on metasurface-inspired antenna design and their theoretical perspectives on performance enhancements are discussed. By adopting the discussed theories, novel metasurfaces are developed and proposed that analyze impedance-bandwidth enhancement, gain enhancement, and SAR reduction. For designing the metasurfaces, initially a conventional rectangular unit cell (CRUC) is theoretically developed using transmission line model at 2.45GHz. Following that, the CRUC-based metasurface is incorporated with a monopole antenna, which enhanced the impedance-bandwidth from 140 MHz to 320 MHz and the gain from 2.5 dB to 7.4 dB. On the body, the presence of the metasurface retains all the performances as free space, with a reduced 1 g SAR of 0.034 and 10 g SAR of 0.024 W/kg. 1. INTRODUCTION In the modern era of technology, academics, researchers, and engineers are increasingly focusing on the development of unique metasurfaces due to their extensive use in wireless communication at microwave frequencies [1–3]. Metasurface is a form of metamaterial [4–13] where metallic unit cells are arranged on the surface of metal-backed two-dimensional dielectric substrates. These arrangements, along with the specific shape, geometry, and size of the structures, can influence EM manipulation and possess certain beneficial characteristics that do not occur in nature. The beneficial characteristics include the blocking, absorbing, and bending of EM waves for a certain range of frequencies, which is not possible using conventional materials. These metasurface functionalities classify metasurface as an artificial magnetic conductor (AMC) [14–16], high impedance surface (HIS) [17, 18], and electromagnetic band gap (EBG) [19, 20]. AMC and HIS possess the same type of characteristics, which are perfect magnetic conductor (PMC) behaviors, whereas the EBG possesses not only PMC-like behavior but also suppresses the surface wave flowing on it over a certain range of frequencies known as band gap. The above metasurface may use metallic vias between the ground plane and unit-cell through the dielectric substrate to increase inductance. This type of structure is known as a mushroom-like structure. The absence of metallic vias is known as via-free metasurface or uni-planar metasurface [3]. The manipulation of propagation of EM wave by the metasurface enhances the antenna performances. To summarize the application of metasurfaces and their development for performance improvement, researchers have proposed review articles [21,22]. These articles have addressed the Received 5 May 2023, Accepted 22 June 2023, Scheduled 9 July 2023 * Corresponding author: Nibash Kumar Sahu (nibash11@gmail.com). The authors are with the Department of Electronics & Instrumentation Engineering, Odisha University of Technology and Research, Bhubaneswar, Odisha, India.