A dual‐band optically transparent antenna based on a slotted interconnected ring resonator as an efficient radiating element is proposed. The compact radiating element and partial ground plane are structured on a plexiglass substrate with Silver Tin Oxide as transparent conducting material. The radiation disadvantage of OTAs due to the low conductivity of conductive oxides has been overcome with the gain improvement technique of 2 × 1 antenna array design. The overall sizes of the proposed single element and 2 × 1 two element array antennas are λ/2.5 × λ/2.5 and λ/1.19 × λ/2.08 at the lower resonance frequency of 2.4 GHz, respectively. The operation bands of both OTA prototypes cover WLAN and WiMAX frequency bands with permissible bandwidth and sufficient gain therefore the 2 × 1 antenna array is utilized as one of two dual‐band antennas of a 2 × 2 MIMO transceiver system for WLAN and WiMAX band operations.
An ultrathin dual-layer flexible metamaterial absorber with triple-band for RF energy harvesting applications has been reported in this article. The sub-wavelength unit cell of the proposed absorber is composed of six distinct concentric annular having outer circumference of ring and octagonal inner circumference. The metallic resonators are constructed from copper foil self-adhesive tape which are affixed on flexible neoprene rubber sheet terminated by metal ground plate. The proposed absorber prototype is ultrathin and compact with the thickness less than 0.037λ 0 and cell size less than 0.2λ 0 at the lower absorption frequency of 1.75 GHz. Flexible dual-layer absorber exhibits triple absorption peaks of 96.91%, 96.41% and 90.12% at 1.75 GHz, 2.17 GHz and 2.6 GHz with full width at half maximum (FWHM) bandwidth of about~6.5%. The RF performance of proposed absorber is numerically computed for different polarization and incidence angle variations. The absorption value is above 76% for the oblique incidence angle up to 45 in TE mode operation, whereas the absorption value is 94% for oblique incidence angle up to 60 in TM mode operation. The measured outcomes are in agreement with the numerically calculated results. The energy harvesting potential of the proposed absorber structure is numerically confirmed by the resulting improved RF absorption value in dependence to different resistive loading of the polarization insensitive unit cells. K E Y W O R D S energy harvesting, metamaterial, metamaterial absorber
This article proposes a novel rectenna design based on modified Hilbert fractal shaped microstrip antenna and Villard voltage doubler rectifying circuit for RF energy harvesting applications operating at Global System for Mobile Communications (GSM) 900 MHz band. The energy harvesting antenna is numerically optimized and fabricated on a Rogers RO4003 substrate of thickness 1.52 mm with a compact overall physical sizes of 80 mm × 82 mm (λ 0 /4.16 × λ 0 /4.06). Various geometric parameters and circuit component values of the proposed energy harvesting system are optimized in order to achieve a matched input impedance with good radiation performance of high gain for the input power level less than −20 dBm. The numerical and experimental results point out the technical potential of the proposed rectenna design to be utilized in DC power supply modules of low voltage, low power electronic devices. K E Y W O R D S fractal antenna, RF energy harvesting system, Villard voltage doubler
This paper proposes a novel rectenna design for the compact RF energy harvesting system operating at 900 MHz. The rectenna design is based on a probe fed split-ring resonator on an elliptical slotted ground plane and an RF-DC rectifying circuit in the form of Villard voltage doubler circuit. The energy harvesting antenna is numerically modeled and fabricated on a 1.524 mm thick Rogers RO4003C substrate with a compact overall size of 81.25 mm 87.5 mm (λ 0 /4.1 λ 0 /3.8). The measured reflection coefficient indicates the proposed energy harvesting antenna to operate at 890 MHz with 51.3 MHz bandwidth covering GSM 900 band. As an RF-DC rectifying electronic circuit, a one stage voltage doubler circuit based on zero bias Schottky barrier diode in conjunction with the inductive impedance matching and λ/4 impedance transformer circuits has been designed. The DC voltage of nonlinear RF rectifier circuit is obtained as 1.7 V at the output load for-11 dBm input power level. The measured and simulated results confirm the proposed rectenna system to have a technical potential for the operation of low power and low voltage electronic devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.