dBm Input Power Research Articles

Capacitive coupled circular patch antenna based rectenna systems for 5.8 GHz wireless power transfer applications

This paper, a two- and four-element linear array of capacitively coupled microstrip patch antenna have been presented for 5.8 GHz wireless power transfer application. Initially, a 5.8 GHz matched rectifier has been designed that produces maximum 1.54 V output voltage across a 1.8 kΩ load for 4 dBm input power. The maximum calculated efficiency is found to be 52.70%. The rectifier was then connected with a spurious free antenna to form a rectenna, which provided 0.39 V output voltage across the load and maximum 34.34% efficiency for received power of 0.246 mw. Since efficiency was found low, next, an attempt has been made to increase the efficiency by increasing antenna gain. To do this, a two-element and a four-element linear array of the antenna have been formed and connected with the rectifier to form the rectennas. To suppress spurious responses of arrays C-shaped slot etched on ground and U-shaped stub is placed at microstrip feed line. The two- and four-element array showed 11.4 dB and 15 dB gain, respectively, at 5.8 GHz (compared to 4.17 dB of the single element antenna). Maximum output voltages and efficiencies of the rectenna formed using two and four-element arrays are 0.83 V, 0.915 V and 45.06%, 52.55% respectively.

A High-Efficient Wireless Power Receiver for Hybrid Energy-Harvesting Sources

This article presents a power-efficient hybrid energy-harvesting system that scavenges energy from solar, vibration, and radio frequency (RF) energy sources and converts into regulated output dc voltage courtesy buck–boost dc–dc converter. The proposed architecture incorporates tetra-paths for maintaining high power conversion efficiency (PCE) over extended input power range (−10 to 30 dBm). A time-domain maximum power point tracking technique is proposed for solar energy harvester. A high-efficiency full wave rectifier is designed for triboelectric rectifier. A 5.8-GHz RF-dc converter with adaptive matching is proposed to increase dynamic range of the input power. The chip is implemented in 0.18-µm bipolar-CMOS-DMOS process. The die area of the chip is 2.8 mm × 5.0 mm, including the pads. The solar and triboelectric energy harvesters achieve a measured peak efficiencies of 75.4% and 92.3%, respectively. The high-power 5.8-GHz RF-dc converter achieves measured PCE of 76% at 30 dBm input power. The low-power dual-band RF-dc converter operating at 900 MHz and 2.4 GHz obtains measured peak efficiencies of 73% and 71.9% at 0 dBm input, respectively. The buck–boost dc–dc converter employed in the proposed hybrid energy harvesting system achieves a measured peak PCE of 94.5%.

Theoretical study on ultra-broadband gain and low noise characteristics of PbS quantum dots-doped silica fiber amplifier

To study the performance of the PbS quantum dots (QDs)-doped silica fiber amplifier (PQDFA), here, a model of PQDFA with ultra-broadband gain and low noise is theoretically proposed. Based on this model, the impact of fiber structure, pump/signal power, and PbS QDs properties on the noise figure (NF) of PQDFA is investigated. The simulation results show that pump/signal light power changes the NF of PQDFA by affecting the population inversion level. Besides, the Stokes-shift and doping concentration proportion of QDs also affect the performance of fiber amplifiers. In addition, the gain and NF spectrum of single- and multi-sized PQDFA are simulated and compared. The simulation results show that the working band of PQDFA is determined by the QDs’ emission spectra, and wavelength tunability can be achieved by changing the QDs’ distribution in fiber. For the multi-sized PQDFA proposed in this paper, under −10 dBm input signal power, the 3 dB bandwidth, highest gain, and lowest NF in 1300–1500 nm band are 107 nm, 29 dB, and 3.84 dB, respectively.

Optimization of Rectifying Circuit for RF Energy Scavenging

This paper studies a rectifier design for radio frequency energy scavenging at 2.45 Ghz ISM band. The designs of a voltage doubler rectifier that enable RF to DC conversion consists of two units of Schottky diode. This paper also covers the analysis of six zero bias Schottky diodes. The Schottky rectifier is widely used due to their switching speeds that can approach zero time and give very small forward voltage drops. It does allow the circuit to operates at very high frequency and very low power input signals. The rectifying circuit is designed, simulated and measured in this study by using Agilent Advanced Design System (ADS) at 2.45 GHz. The conversion efficiency of proposed rectifier with HSCH-9161 diode gives 31.16%. The rectifier reaches the highest efficiency at 20 dBm input power, which reliable to commercial Wi-Fi access point that operates at 10 to 25 dBm. The higher output voltage is 10.32 V at 20 dBm.

RF Small and large signal characterization of a 3D integrated GaN/RF-SOI SPST switch

AbstractThis paper presents the radio frequency (RF) measurements of an SPST switch realized in gallium nitride (GaN)/RF-SOI technology compared to its GaN/silicon (Si) equivalent. The samples are built with an innovative 3D heterogeneous integration technique. The RF switch transistors are GaN-based and the substrate is RF-SOI. The insertion loss obtained is below 0.4 dB up to 30 GHz while being 1 dB lower than its GaN/Si equivalent. This difference comes from the vertical capacitive coupling reduction of the transistor to the substrate. This reduction is estimated to 59% based on a RC network model fitted to S-parameters measurements. In large signal, the linearity study of the substrate through coplanar waveguide transmission line characterization shows the reduction of the average power level of H2 and H3 of 30 dB up to 38 dBm of input power. The large signal characterization of the SPST shows no compression up to 38 dBm and the H2 and H3 rejection levels at 38 dBm are respectively, 68 and 75 dBc.

Modified Class-F power amplifier design with fundamental frequency output impedance load

A modified Class-F power amplifier with medium output power at 433 MHz was designed, simulated and implemented in this paper. The design process used a load condition of 1) output impedance of the amplifier at the fundamental frequency, 2) short-circuit loads at the even harmonics and 3) open-circuit loads at the odd harmonics. By biasing the circuit to be a typical Class-F, the circuit yielded moderate efficiency as the load condition was different from the optimum one. By strongly biasing the circuit toward that of Class-A, the load condition approached the optimum, but the circuit still yielded moderate efficiency due to the low efficiency nature of a Class-A amplifier. By proper choice of the operating point in Class-AB, a prototype circuit, with 9 dBm input power, yielded a maximum PAE of 68.5% with output power 21.8 dBm. Furthermore, at 11 dBm input power, the prototype yielded a better PAE 79.6% with 23.2 dBm output power. Our design procedure did not need expensive load-pull equipment.

5G Visible Light Communication - OCDMA Setup using Catenated-OFDM Modulation Method

This paper demonstrates a new high-speed architecture of visible light communication (VLC) system combining with zero cross correlation (ZCC) code of optical code division multiplexing (OCDMA) and novel catenated-OFDM modulation scheme. In order to achieved high spectral efficiency and higher bit rate system for 5G application, we embedded multiband catenated-OFDM modulation technique and OCDMA in VLC design system. Moreover, by employing visible laser diode (VLD) in designing VLC system, we achieved 10 Gbps bit rate at 2.5 dBm input power. We investigate this new combination system design to analyze the bit rate and bit error rate (BER) in 3 m indoor VLC channel propagation.

High birefringence and broadband dispersion compensation photonic crystal fiber

Abstract We propose a perfectly square lattice photonic crystal fiber (PCF) which shows high birefringence and negative dispersion. To set up high asymmetry in the core, dual line imperfection is considered where the fill fraction ratio and defect air hole diameter exhibit significant impact on dispersion and birefringence. Numerical analyses of guiding properties of the proposed PCF are done using finite element method with perfectly matched layer boundary condition from 1.2 to 1.8 μm wavelength. The optimized square lattice PCF presents high birefringence of 2.48 × 10−2 and dispersion of −777.66 (ps/nm.km) at 1.55 μm wavelength. In addition, the proposed PCF offers ultra-low confinement and insertion loss at 1.55 μm wavelength. Moreover, −0.45 (ps/nm2.km) dispersion slope and 0.0045 nm−1 relative dispersion slope are observed at 1.55 μm wavelength. Additionally, the proposed PCF maintains dispersion and birefringence variation of ±30 (ps/nm.km) and ±0.00001 between 1.5 and 1.6 μm wavelength ranges, respectively. Furthermore, the proposed PCF shows high quality factor and low bit error rate at 10 dBm input power. We believe the proposed square lattice PCF can be deployed in wavelength division multiplexing based optical fiber transmission system for wide-band dispersion compensation.

Design of a Rectenna in 2.45 GHz Band Frequency for Energy Harvesting

There are several sources of energy recovery in the ambient environment. The radiofrequency energy harvesting system is used to harvest the electromagnetic energy in the air by processing energy sources to charge low-power electronic devices. Rectenna termed as a rectifying antenna is a device that is used to convert electromagnetic waves in the air into direct electric current. In this work, we have designed firstly the patch antenna with a small size printed on the FR4 substrate (40 mm × 47.5 mm × 1.6 mm) and then the rectifier circuit. This rectenna is capable of working at a frequency range of 2.45 GHz. The antenna was designed using High Frequency Structure Simulator (HFSS) 13.0 software with the result of working frequency of 2.453 GHz, S11 (Return Loss) -52 dB, Voltage Standing Wave Ratio (VSWR) 1.036, gain 3.48 dB and bandwidth 150 MHz. The efficiency of rectifier design on Advanced Design System (ADS) 2011 software is 54% at the input power of 0 dBm at 2.45 GHz. The resulting system is capable of producing electrical energy to power low-power electronic equipment at a DC voltage of 732 mV.

Design and Analysis of Wideband Rectenna for IoT Applications

This work addresses the design analysis of a wideband rectifier for the broadband frequencies at 1GHz to 5GHz. In the paper, a new broadband antenna with a compact rectifier circuit is analyzed. Here, two types of rectifier circuits are analyzed: First rectifier circuit with HSMS series HSMS 270B Schottky diode and Second circuit with MOTOROLA series 5456a diode. Comparative analysis of both the circuit is also shown. Dual diode topology is introduced to enhance the performance of rectenna (Antenna with Rect ifier) in terms of power conversion efficiency (PCE). According to the simulation it shows, the second rectifier circuit with a proposed antenna shows a better efficiency response. From this device observed RF power at the output is 16.599dBm, 45.7mW, and 70.58% PCE at 0dBm input power. The proposed rectenna enables the power supply of low-power IoT devices that require the minimum power required to operate.

Simple Adaptive Rectifier with High Efficiency over a Range of 21 dBm Input Power for RF Energy Harvesting Applications

This paper presents a novel simple adaptive and efficient rectifier for Radio Frequency (RF) energy harvesting applications. Traditional rectifiers have maximum RF-DC Power Conversion Efficiency (PCE) over a narrow range of RF input power due to diode breakdown voltage restrictions. The proposed adaptive design helps to extend the PCE over a wider range of RF input power at 2.45GHz using a simple design. Two alternative paths arecontrolled depending on the RF input power level. Low input power levels activate the first path connected to a single rectifier; low power levels make the diode operate below its breakdown voltage and therefore avoiding PCE degradation. High input power levels activate the second path dividing it into three rectifiers. This keeps input power at each rectifier at a low power level to avoid exceeding the diode break down voltage. Simulated PCE of this work is kept above 50% over a range of 21.4 dBm input power from -0.8dBm to 20.6dBm.

Transmission Lines-Based Impedance Matching Technique for Broadband Rectifier

A high-efficiency compact broadband rectifier is developed for wireless energy harvesting. A novel three-stage impedance matching technique is utilized in a broadband rectifier design to achieve high conversion efficiency with a compact size. In the rectifier, a low loss impedance matching technique is initiated by employing a linearly tapered transmission line for controlling the impedance curve at the required input power level, followed by two stages to make a circular impedance curve for wideband impedance matching. Both theoretical analysis and numerical simulations of the proposed rectifier are performed. For validation, a prototype is fabricated and demonstrated a broadband performance with a fractional bandwidth (FBW) of 74% (from 1.12 to 2.43 GHz) and power conversion efficiency of more than 50% at a 5 dBm input power level. Moreover, the rectifier can reach an efficiency of more than 50% extending from 0.97 to 2.55 GHz (FBW = 90%) at the input power of 10 dBm, which is the highest bandwidth reported under this condition. This low complexity design is suitable for realizing broadband rectifiers for wireless energy harvesting (WEH) applications.

Compact Rectifiers With Ultra-wide Input Power Range Based on Nonlinear Impedance Characteristics of Schottky Diodes

Two high-efficiency radio-frequency (RF) rectifiers with extended input power range are proposed by taking the advantage of nonlinear impedance characteristics of diodes. Each rectifier consists of two subrectifiers that operates at high- and low-power levels, respectively. A nonlinear power division strategy is applied to the input power level without any power dividers or couplers. A λ/8 transmission line is introduced to compensate the imaginary part of diode impedance. A λ/4 transmission line is applied to reverse the diode impedance variation with respect to the input power. Two rectifiers operating at 2.45 GHz are fabricated and measured. Rectifier I shows a RF-dc power conversion efficiency exceeding 50% over an input power range of 23.3 dB (from 6.5 to 29.8 dBm), with maximum efficiency 74.5% at 27 dBm input power. Rectifier II shows an input power range exceeding 50% over 31 dB (-1 to 30 dBm) with maximum efficiency of 68.5% at 28 dBm.

Performance analysis of high speed backward compatible TWDM-PON with hybrid WDM–OCDMA PON using different OCDMA codes

In this paper, a backward compatible bidirectional 160/40 Gbps time and wavelength division multiplexing-passive optical network with hybrid wavelength division multiplexing optical code division multiple access PON (WDM–OCDMA PON) has been proposed. Six OCDMA codes have been used to enhance the security and users’ ability to access shared bandwidth of an optical network. In this “pay-as-you-grow” supported system, the fiber impairment effects have been effectively reduced. The performance of the proposed system has been analyzed for variable input power (4–19 dBm) and transmission distance (10–70 km) supporting 120 active users under the influence of fiber nonlinearities, attenuation, dispersion and noise. Based on the numerical calculations, the proposed system using modified quadratic congruence (MQC) code is shown to provide better performance compared to multi diagonal, hadamard, zero cross-correlation (ZCC), shift ZCC and flexible cross-correlation codes. To validate the numerical analysis, the simulation of the proposed system at 160/40 Gbps data rate for 70 km downstream and greater than 70 km upstream fiber link transmission at 10−9 BER limit for 68 active users have been successfully demonstrated. Also, it has been shown that MQC code provides optimum results at 10 dBm input power over 55 km distance and supports more than 120 active users with high gain of − 1.97 dB and low noise figure of 2 dB. Further, the comparative performance of the proposed system with the previous latest works in literature reveals a superior performance of the system.

Compact Rectifier Circuit Design for Harvesting GSM/900 Ambient Energy

In this paper, a compact rectifier, capable of harvesting ambient radio frequency (RF) power is proposed. The total size of the rectifier is 45.4 mm × 7.8 mm × 1.6 mm, designed on FR-4 substrate using a single-stage voltage multiplier at 900 MHz. GSM/900 is among the favorable RF Energy Harvesting (RFEH) energy sources that span over a wide range with minimal path loss and high input power. The proposed RFEH rectifier achieves measured and simulated RF-to-dc (RF to direct current) power conversion efficiency (PCE) of 43.6% and 44.3% for 0 dBm input power, respectively. Additionally, the rectifier attained 3.1 V DC output voltage across 2 kΩ load terminal for 14 dBm and is capable of sensing low input power at −20 dBm. The work presents a compact rectifier to harvest RF energy at 900 MHz, making it a good candidate for low powered wireless communication systems as compares to the other state of the art rectifier.

Design of L-S band broadband power amplifier using microstip lines

This contribution introduces a novel broadband power amplifier design, operating in the frequency band ranging from 1.5 GHz to 3 GHz which cover the mainstream applications running in L and S bands. Both matching and biasing networks are synthesized by using microstrip transmission lines. In order to provide a wide bandwidth, two broadband matching techniques are deployed for this purpose, the first technique is an approximate transformation of a previously designed lumped elements matching networks into microstrip matching circuits, and the second technique is a binomial multi-sections quarter wave impedance transformer. The proposed work is based on ATF-13786 active device. The simulation results depict a maximum power gain of 16.40 dB with an excellent input and output matching across 1.5 GHz ~ 3 GHz. At 2.2 GHz, the introduced BPA achieves a saturated output power of 16.26 dBm with a PAE of 21.74%, and a 1-dB compression point of 4.5 dBm input power level. The whole circuitry is unconditionally stable over the overall bandwidth. By considering the broadband matching, the proposed design compares positively with the most recently published BPA.

RF Energy Harvesting using Cross-couple Rectifier and DTMOS on SOTB with Phase Effect of Paired RF Inputs

In this paper, the design and evaluations of a cross-couple rectifier (CCR) with floating sub-circuit using Dynamic Threshold MOSFET (DTMOS) for RF energy harvesting is presented. The circuit is fabricated using 65nm Silicon on Thin Buried Box (SOTB) CMOS technology. The measurement result shows that circuit exceeds 1000 mV DC output at -14 dBm input power and obtains 48 % power conversion efficiency (PCE) at a level of -10 dBm input power. The proposed circuit generated 0.9 μW DC output power at a level of -21 dBm input power which equivalent to 10.6 % PCE when harvesting the 950 MHz LTE signal in the ambient environment. The study also indicates the effect of phase difference between the two RF input signals on the DC output voltage in CMOS CCR. The DC output voltage depends on the phase of the two RF input signals and reaches a maximum when the phase difference between the two RF signals is π. Experimental results demonstrate that the output voltage changes from 950 mV to -100 mV when the phase difference varies from π to 0 at an RF input power of -10 dBm. When the rectifier receives an RF signal from the environment at an input power of -21 dBm, the DC output voltage changes from 300 mV to -50 mV when the phase changes from π to 0.

An ultra‐wideband rectenna using optically transparent Vivaldi antenna for radio frequency energy harvesting

This paper presents a novel ultra-wideband rectenna which consists of a transparent Vivaldi antenna and a wideband rectifying circuit for radio frequency energy harvesting. The antenna is realized on a 2.2-mm-thick soda-lime glass substrate coated with fluorine-doped tin oxide of thickness 650 nm. It provides an optical transmittance greater than 80% in the visible region. The rectifying circuit with a cascaded matching network and the Greinacher doubler circuit are fabricated on an FR4 substrate with a thickness of 0.8 mm. The antenna provides the best matching characteristics and the realized peak gain is 3.2 dBi. The designed matching network enables maximum power transfer from the antenna to the rectifier. The rectenna provides a peak power conversion efficiency of 69% for −10 dBm input power. The proposed antenna can be realized on the windscreen of automobiles and glass windows without causing any obstruction to normal view.

A 2.45 GHz High Efficiency CMOS RF Energy Harvester with Adaptive Path Control

In this research work, a reconfigurable 2.45-GHz RF-DC converter realized in a 180-nm complementary metal-oxide semiconductor (CMOS) technology is proposed to efficiently harvest electromagnetic energy. The proposed circuit is composed of a low-power path rectifier, a high-power path rectifier, and an adaptive path control (APC) circuit. The APC circuit is made-up of a comparator, two switches, and an inverter. The APC circuit senses the output voltages of the low-power path and the high-power path rectifiers and generates a control signal to automatically switch the proposed circuit between the lower-power path and the high-power path operation depending upon RF input power level. The proposed circuit obtains more than 20% measured power conversion efficiency (PCE) from −6 dBm to 11 dBm input power range with maximum efficiencies of 41% and 45% at 1 and 6 dBm input powers, respectively, for 5 kΩ load resistance. In addition, the proposed circuit shows excellent performance at 900 MHz and 5.8 GHz frequencies.

Quad-Band 3D Rectenna Array for Ambient RF Energy Harvesting

This paper presents a quad-band, 3D mountable rectenna module for ambient energy harvesting. With the aim of powering up Internet of Things (IoT) nodes in practical ambient environments, a hybrid approach of combining power, both at RF and DC, is adopted using 98 MHz FM band, GSM900 (Global System for Mobile Communications), GSM1800, and Wi-Fi 2.4 GHz band. A dual polarized cross-dipole antenna featuring asymmetric slots as well as central ring structure enables multiband response and improved matching at the higher three frequency bands, whereas a loaded monopole wire antenna is used at the lower FM band. Four identical multiband antennas are placed in a 3D cubic arrangement that houses a 4-to-1 power combiner and matching circuits on the inside and the FM antenna on the top. In order to maintain stable rectenna output at varying input power levels and load resistances, a novel transmission line based matching network using closed form equations is proposed. Integrated in form of a 10 × 10 × 10 cm3 cube using standard FR4 substrate, the rectenna generates a peak output voltage of 2.38 V at −10 dBm input power. The RF to DC conversion efficiency is 70.28%, 41.7%, 33.37%, and 27.69% at 98 MHz, 0.9 GHz, 1.8 GHz, and 2.4 GHz, respectively, at −6 dBm. The rectenna also exhibits a measured conversion efficiency of 31.3% at −15 dBm for multitone inputs in ambient environment. The promising results in both indoor and outdoor settings are suitable to power low power IoT devices.