Novel miniaturized folded UWB microstrip antenna‐based metamaterial for RF energy harvesting

Abstract

Summary This paper presents a design of an ultra‐wideband (UWB) cylindrical metamaterial (MTM) antenna for radio frequency (RF) energy harvesting to suit the fields of Internet of Things (IoT) applications. The patch circuitry is based on 3×5 Hilbert‐shaped MTM unit cells array to enhance the antenna bandwidth. While, the antenna ground plane is defected with an electromagnetic band gap structure to enhance the gain. The antenna is mounted on a polytetrafluoroethylene cylindrical substrate of an outer diameter of 15 mm and length of 32 mm with 1 mm in thickness. The substrate relative permittivity is 2.04, and the loss tangent is 0.0002. The antenna patch and the ground plane structures are printed with silver nanoparticles ink using a 2.5D CNC plotter machine. The fabricated prototype provides an UWB over the frequency range from 3.77 up to 13.89 GHz with a first separate resonant mode at 3 GHz. The antenna performance is tested numerically using two different software packages of CST MWS and HFSS. Then, an experimental validation is conducted to realize the performance of the proposed antenna in harvesting the RF energy. Excellent conversion efficiency, about 90%, is achieved at 5.8 GHz. Finally, the antenna radiation patterns and S11 spectrum are measured and compared against their simulated results to achieve good agreements.

Further realization of a flexible metamaterial-based antenna on indium nickel oxide polymerized palm fiber substrates for RF energy harvesting

“…From the obtained results, the INP prototype shows excellent immunity against bending effects in comparison to the one based on FR4 substrate that is attributed to μ r component of the INP substrate [14]. In another word, the advantage in using INP material is the magnetic field energy can be stored in the INP substrate to help the antenna to radiate regardless the value of the bending angle [20].…”

“…A multi-resonant fractal MTM antenna based on a CPW excitation was developed in [19]. A rectangular MTM array patch mounted on a substrate layer of a defected ground plane was invented in [20] for UWB applications.…”

“…Recently, the performance of microstrip antennas has been enhanced with the introduction of metamaterial (MTM) structures [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For instance, split-ring resonator arrays were applied in printed circuit microwave devices for size reduction [5] with increasing the gain-bandwidth products [6].…”

Further investigation on solant–rectenna‐based flexible Hilbert‐shaped metamaterials

“…As seen in Fig. 14, the RF harvester with an HSMS 2860 Schottky diode chip as a matching circuit [27] between the solant load and the circuit rectifier impedance is connected. The measurement setup, in free space open field environments, involves a printed omni directional vertically polarised dipole antenna with a realised gain of 1.56 dBi at 0.915 GHz located at 20 m from the proposed rectenna.…”

“…As seen in Fig. 14, the RF harvester with an HSMS 2860 Schottky diode chip as a matching circuit [27] between the solant load and the circuit rectifier impedance is connected. The measurement setup, in free space…”