The objective of this paper is to investigate the performance of a Rectangular patch antenna, in terms of its bandwidth, gain and directivity, operating in the X-band (8-12) GHz. The introduction of a composite structure having simultaneous negative permittivity and negative permeability, called double negative metamaterial or left handed material (LHM) as a superstrate layer above an antenna will affect the antenna's basic performance characteristics, such as gain, Bandwidth, directivity and radiation efficiency. The LHM structure used is a single unit cell, which is a combination of a Hexagonal Split Ring Resonator (H-SRR) and a Capacitive Loaded Strip (CLS). The range of resonant frequencies and the corresponding negative values of permeability (μr) and permittivity (εr) is observed. The incorporation of a 9 × 9 array LHM structure with a single Rectangular patch Antenna, enhanced the Antenna's performance characteristics. Simulated numerical results indicate an increasing gain with a value of 6.53 dB and directivity of 8.129 dBi. The bandwidth of the proposed antenna is measured to be 4.65%. © 2018 Electromagnetics Academy. All rights reserved.