This paper focuses on enhancing the bandwidth and gain of a coaxially fed microstrip patch antenna using Near Zero Refractive Index (NZRI) Metasurface. A metasurface comprising closely spaced 4 × 4 concentric circular rings is proposed to generate a wideband NZRI surface. The proposed metasurface provides µ_eff = 0.0018 and ϵ_eff = 4.4, making its refractive index near zero (i.e. – η_eff = 0.09) at 2.4 GHz. It is a wideband structure with an effective refractive index of less than 0.14 in 1–3 GHz. The metasurface is arranged over a coaxially fed microstrip square patch antenna to enhance its gain and bandwidth. The antenna and metasurface are printed on FR4 substrate of thickness 1.6 mm and dielectric constant 4.4 to verify its performance. A patch antenna is designed to operate near 2.4 GHz. A prototype of size (0.72λ × 0.72λ × 0.048λ) is fabricated and tested. The metasurface can improve the gain of the developed patch antenna by 4.3 dB and bandwidth by 11.5% (i.e. 45 to 320 MHz) at 2.4 GHz. 1 dB gain bandwidth is the same as that of impedance bandwidth.