Radio frequency (RF) energy transfer and harvesting techniques have recently become alternative methods to power the next-generation wireless networks As this emerging technology enables proactive energy replenishment of wireless devices, it is advantageous in supporting applications with quality-of-service requirements In this paper, we present a comprehensive literature review on the research progresses in wireless networks with RF energy harvesting capability, which is referred to as RF energy harvesting networks (RF-EHNs) First, we present an overview of the RF-EHNs including system architecture, RF energy harvesting techniques, and existing applications Then, we present the background in circuit design as well as the state-of-the-art circuitry implementations and review the communication protocols specially designed for RF-EHNs We also explore various key design issues in the development of RF-EHNs according to the network types, ie, single-hop networks, multiantenna networks, relay networks, and cognitive radio networks Finally, we envision some open research directions

Wireless Networks With RF Energy Harvesting: A Contemporary Survey

Look to this new, cutting-edge microstrip antenna book for the first exhaustive coverage of broadband techniques, including the most up-to-date information to help you choose and design the optimum broadband microstrip antenna configurations for your applications, without sacrificing other antenna parameters. The book shows you how to take advantage of the lightweight, low volume benefits of these antennas, by providing clear explanations of the various configurations and simple design equations that help you analyze and design microstrip antennas with speed and confidence. This practical resource offers you a comprehensive understanding of the radiation mechanism and characteristic of microstrip antennas, and provides guidance in designing new types of planar monopole antennas with multi-octave bandwidth. You learn how to select and design proper broadband microstrip antenna configurations for compact, tunable, dual-band and circular polarization applications. Moreover, the book compares all the broadband techniques and suggests the most attractive configuration. Extensively referenced with over 300 illustrations and 140 equations.

Broadband Microstrip Antennas

This paper presents a novel single-patch wide-band microstrip antenna: the E-shaped patch antenna. Two parallel slots are incorporated into the patch of a microstrip antenna to expand it bandwidth. The wide-band mechanism is explored by investigating the behavior of the currents on the patch. The slot length, width, and position are optimized to achieve a wide bandwidth. The validity of the design concept is demonstrated by two examples with 21.2% and 32.3% bandwidths. Finally, a 30.3% E-shaped patch antenna, resonating at wireless communication frequencies of 1.9 and 2.4 GHz, is designed, fabricated and measured. The radiation pattern and directivity are also presented.

Wide-band E-shaped patch antennas for wireless communications

This paper presents a study of a novel monopole antenna for ultrawide-band (UWB) applications. Printed on a dielectric substrate and fed by a 50 /spl Omega/ microstrip line, a planar circular disc monopole has been demonstrated to provide an ultra wide 10 dB return loss bandwidth with satisfactory radiation properties. The parameters which affect the performance of the antenna in terms of its frequency domain characteristics are investigated. A good agreement is achieved between the simulation and the experiment. In addition, the time domain performance of the proposed antenna is also evaluated in simulations.

Study of a printed circular disc monopole antenna for UWB systems

Review on the criteria anticipated for the fabrication of highly efficient ZnO-based visible-light-driven photocatalysts

In this paper, a broadband dumbbell shape slot antenna in the frequency range of 5.21-8.46 GHz and double elliptical shape slot in the frequency range of 4.49-8.7 GHz are designed. Dumbbell slot provides 47.5% bandwidth (BW) for $\vert \mathrm{S}_{11}\vert \leq-10\ \text{dB}$ and maximum gain of 3.2 dBi at 6.56 GHz and double elliptical slot provides 63.8% BW for $\vert \mathrm{S}_{11}\vert \leq-10\ \text{dB}$ with maximum gain of 6.8 dBi at 5.1 GHz. Dumbbell Slot has dimensions of 0.52\lambda_{0}\times 1.17\lambda_{0}$ and double elliptical has dimensions of 0.38\lambda_{0}\times 0.88\lambda_{0}$ at 5.8 GHz. The designed antennas are fabricated and simulated results are validated with measured results.

Dumbbell and Double elliptical printed slot antennas for wideband applications

In this paper, broadband linearly polarized rectangular microstrip antenna with U-slot in S-Band frequency is designed. The antenna has been analyzed using the FEM-based HFSS software. The characteristics of an individual antenna and antenna system have been studied by placing them on a cylindrical surface of 400mm diameter to get omni-directional coverage. These antennas are flush to the surface of the cylindrical body whichfer zero aerodynamic drag. The antenna requires dielectric cover over the radiating element to protect from heat, physical damage and environmental constraints. The 10dB return loss bandwidth is around 100 MHz at 2.25 GHz. The single antenna mounted on cylindrical body has a minimum gain of 6dBi over the bandwidth. The HPBW of antenna is 72° in roll plane and 94° in its orthogonal plane. The antenna system with two antennas mounted on diametric opposite side of cylindrical body gives coverage better than 85% for dip in the pattern upto −10dB.

Broad Band Omni Directional Antenna System for Onboard Telemetry Applications

A 2nd order bandpass filter using tapped-fed λ/2 hairpin resonators with unequal-length arms is presented. The proposed filter geometry introduces a transmission zero (TZ) in the upper and lower stopbands simultaneously. The frequencies of the TZs can be controlled by changing the lengths of the resonator arms. A single stub matching network is proposed to improve impedance matching after the TZs are re-configured. The proposed matching network introduces an additional configurable TZ in the upper stopband. The design offers several degrees of freedom to alter the passband and stopband performance. The overall dimensions of filter are 0.18λ × 0.3λ.

A Simple Technique for Multiple Configurable Transmission Zeros in λ/2 Resonator Filters

This paper presents design of a wideband bandpass filter exhibiting high passband selectivity and ultra-wide stop-band with high rejection levels. The design is based on mixed lumped and distributed elements. A wideband cell, consisting of two series LC tank circuits coupled through an open-ended microstrip stub, provides a quasi-elliptic passband with wide bandwidth. The tank circuits suppress the harmonic passbands of the open stub to a certain extent, which is enhanced by integrating sharp-rejection low-pass sections at the access ports of the wideband cell. The novel design of the low-pass sections enable achieving high out-of-band rejection levels. The composite filter exhibits ultra-wide stopband on account of multiple transmission zeros introduced by the constituent circuits. A prototype filter, designed at the center frequency of 0.528 GHz with 3-dB bandwidth of 72.5%, shows rejection better than 42 dB from 1.12 GHz to 6.2 GHz (138.8 %). The measured selectivity factor, defined as the ratio of 3-dB to 30-dB bandwidths, is 0.735. The size of the filter is 0.128 by 0.096 times the wavelength at the center frequency.

High-Selectivity Wideband Filter With Ultra-Wide High-Attenuation Stopband Region Using Mixed Lumped-Distributed Circuits

Ridge waveguide transitions have been used in the high power couplers of many ongoing high intensity proton accelerator projects worldwide. Because of their smaller size and high energy densities, they require strict dimensional tolerances during fabrication and operating conditions. In order to study their electromagnetic characteristics, two different types of transitions with a straight ridge and a tapered ridge are compared using full wave simulations. Apart from the return loss and resonant frequency variation with dimensions, comparative studies on the phase shift, insertion losses, electric and magnetic field distributions and multipacting are also reported. This analysis will be useful in selecting the appropriate ridge waveguide transition for the RF couplers of accelerator cavities.

Girish Kumar

Papers

Dumbbell and Double elliptical printed slot antennas for wideband applications

Broad Band Omni Directional Antenna System for Onboard Telemetry Applications

A Simple Technique for Multiple Configurable Transmission Zeros in λ/2 Resonator Filters

High-Selectivity Wideband Filter With Ultra-Wide High-Attenuation Stopband Region Using Mixed Lumped-Distributed Circuits

Comparative electromagnetic analysis of ridge waveguide transitions for RF power couplers