Miniaturized ENG-Metamaterial Inspired Conformal Antenna with Modified Partial and Backed Ground-Plane for Wearable Applications

In this paper, Epsilon-negative (ENG) metamaterial inspired conformal antenna has been designed at zeroth-order resonance (ZOR) with a stable dipolar type of radiation pattern. The proposed antenna shows an impedance bandwidth of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$9.6 \%(2.38 \text{GHz})$</tex> and operates from 2.27 GHz to 2.5 GHz. The ZOR property has been utilized to miniaturize the size of the antenna with dimensions of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.15 \lambda 0 \times 0.1 \lambda 0 \times 0.008 \lambda 0(13 \text{mm} \times 19 \text{mm} \times 1 \text{mm}$</tex>) where <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda 0$</tex> is the centre frequency. The ZOR has been excited with radial stub-1 acts as a virtual ground, and a meander line provides shunt inductance. The additional radial stub-2 placed in the ground which improves the virtual ground performance and shunt capacitance. The antenna demonstrates the broadside gain of 2 dB and its flexible nature can be beneficial for wearable applications.