High-Gain Electrically Small Modified Antipodal Vivaldi Self-Matched Rectenna for n77/n78/n79 Sub 6 GHz 5G Narrow Dual-Band Wirelessly Powering IoT Devices

This article presents a dual-band, high gain electrically small hexagonal-shaped modified antipodal selfmatched Vivaldi antenna for n77 (3.3-4.2 GHz), n78 (3.3-3.8 GHz), and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{n} 79(4.4-5 \text{GHz})$</tex> applications. By etching dual slots on the radiating patch, the high gain characteristics, viz. 5.19 dBi at 3.74 GHz and 4.97 dBi at 4.9 GHz are achieved. The antenna size is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pi \times\left(\lambda_{0} / 8\right)^{2,}$</tex> and thickness <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda_{0} / 157 (\lambda_{0}$</tex> at 3.74 GHz), and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$k_{0} a=0.8$</tex>, satisfying the condition of an electrically small antenna (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{ka} \leq 1$</tex>). It is designed on a circular-shaped copper-clad substrate, providing dual impedance bandwidth, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3.72-3.78 \text{GHz}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4.86-4.95 \text{GHz}$</tex>, for covering <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{n} 77 / \mathbf{n} 78 / \mathbf{n} 79$</tex> applications. For the rectification purpose, a shunt-diode rectifier circuit topology is executed. For validation, the antenna and rectifier circuit are fabricated and characterized. The power conversion efficiency (PCE) performance is 58.5 % and 63 % at 3.74 and 4.9 GHz, respectively, for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{P}_{\text{in}}=5 \text{dBm}$</tex>.