Non-Uniform Metasurface-Based Omnidirectional Patch Antenna Using Characteristic Mode Analysis

This paper proposes a non-uniform metasurface (MTS) omnidirectional patch antenna for WLAN applications. The antenna configuration is characterized by using characteristic mode analysis (CMA). The proposed non-uniform MTS-based patch antenna comprised a single-layer FR-4 substrate. Non-uniform square-shaped MTS unit cells were present in the upper-substrate layer. The lower-substrate layer is a circular-shaped ground plane. Besides, the excitation method of the proposed non-uniform MTS-based antenna is a single-probe-fed method. The use of a non-uniform square-shaped MTS structure achieved wide frequency resonance, resulting in wide impedance bandwidth. In addition, the circularly rotated direction of current distributions and magnetic fields on the non-uniform MTS structure can generate omnidirectional radiation by Mode 1 at 2.4 GHz (center frequency). The simulated IBW at 2.4 GHz is 26.67% (2.26 - 2.9 GHz). The optimum gain is 4.13 dBic at 2.8 GHz. The proposed antenna exhibits omni-directional radiation characteristics, making it well-suited for wireless communication applications.