Sachin Agrawal

Realization of efficient RF energy harvesting circuits employing different matching technique

Power management and charging of batteries for wireless sensors become a problem when using them in the field applications. In this paper, we present RF energy harvesting circuit with three different approaches: resonator, number of multiplier stages and low pass filter (LPF). Resonator provide 30 times improvement in amplitude of input (100 mV) AC signal. In proposed circuit L type network, between input power source and rectifier, works as resonator as well as matching network at resonant frequency. It results in maximum efficiency 79% with 50kO load at -10 dBm input power. We also present the effect of multiplier stages on output voltage and RF to DC conversion efficiency. Optimum efficiency of approximately 80% is achieved with Dickson topology in input power region 0 to 10dBm for 3rd, 5th and 7th stages, respectively. Application of LPF is also introduced with an existing circuit. It provides 140 mV improvement in output voltage with input power -10dBm. It also shows that maximum efficiency 75% and 64% is possible with dielectric constant (er=9) and substrate height (H=0.0004m), for microstrip line of matching circuit at -10 dBm input power with 10 kO load.

Broadband Rectenna for Radio Frequency Energy Harvesting Application

Abstract A microstrip feed, double-sided printed monopole antenna is presented for radio frequency (RF) energy harvesting application. The antenna structure consists of a circular patch with a truncated ground plane. The ground plane consists of a rectangular notch right below the feed line, which helps to increase the bandwidth of the antenna. In addition, using a rectangular patch in the ground plane increases the effective area of the radiator due to loading effect, which leads to downshifting the lower cut-off frequency, and subsequently bandwidth enhancement. It is found that the ground patch provides the total antenna size reduction of 35.2% along with bandwidth and gain enhancement of 34.7% and 2.03 dBi at 0.9 GHz, respectively. The measured result shows that the proposed antenna offers an impedance bandwidth of 144.5% (0.89–5.53 GHz) with a peak gain of 4.3 dBi. Later, a rectenna system was designed and tested using the developed antenna for a wide range of frequencies. The rectenna system offers the maximum efficiency of 62.5% at 1.8 GHz at the load impedance of 5 kΩ.

Exact Performance Evaluation of RF Energy Harvesting with Different Circuit's Elements

ABSTRACT This paper focuses on various design constraints of radio frequency energy harvesting circuit (RFEHC). Matching networks such as L- and Π-type are used to investigate the RFEHC performance. The simulation results show that the harvesting circuit yields improved output voltage while using a Π-type matching network of high-Q value. Further, a theoretical analysis of matching efficiency and voltage gain under different load conditions and lumped element values is discussed. A tradeoff between the maximum bandwidth and the maximum voltage gain is observed for a given load impedance. Moreover, the influence of various diodes parasitic on the RFEHC bandwidth is also discussed. This analysis shows that low series resistance, high junction capacitance, and high junction resistance of diode are the essential parameters to achieve wide bandwidth. In addition, a microstrip-fed monopole antenna is proposed for ambient RF harvesting. The output voltage varying between 750–800 mV has been obtained by capturing the ambient RF power from the nearby cell tower in the institute.

Calculation of Channel Capacity Considering the Effect of Different Seasons for Higher Altitude Platform System

This paper presents effect of the weather impairments on a high altitude platform (HAP) broadband wireless communication system. It is shown that attenuation due to oxygen, water vapor, fog, cloud, and rain has significant effect on a radio link which is operating in a millimeter frequency range. Channel capacity is calculated for different seasons using Shannon’s channel capacity theorem. The location of HAP is taken to be Delhi (India). Further, it is considered that a user and the HAP platform are stationary.

A dual-band RF energy harvesting circuit using 4th order dual-band matching network

A novel compact rectifier for dual-band operation in the RF energy harvesting is presented. The circuit comprises a 4th order dual-band impedance matching and a single-series circuit with one double diode, both are integrating into a compact shape to occupy a small area of . The merit of the proposed rectifier circuit is that it can be extended to n number of the frequency band by using only matching elements. To validate the design method experimentally, a prototype of a dual-band rectifier is fabricated for two public telecommunication bands of GSM-900 and 1800. In order to reduce the circuit complexity and sensitivity arising due to lumped elements, the meander line and the open stub are used to realize the proposed circuit. A good agreement is obtained between the simulation and the measurement. The measured results show that the proposed rectifier circuit exhibits the conversion efficiency of 25.7 and 65% for an input power of and 0 dBm, respectively. In addition, diode nonlinearity which affects the performance of the rectifier in terms of impedance matching is also investigated.

A Design of Compact Planar Active-Integrated Inverted-F Antenna (AI-PIFA) for Mobile Handsets

A class-E power amplifier integrated with a rectangular ring planar inverted-F antenna (PIFA) is presented in this paper. The proposed PIFA is very compact and occupying less volume 16 × 10 × 5.5 mm3. The measured result shows that the proposed PIFA offers an impedance bandwidth of 250 MHz from 2.3–2.55 GHz, which is useful for LTE band 40 and WLAN (2.4–2.48 GHz). The maximum power-added efficiency (PAE) of class-E power amplifier is found to be 70% at 2.3 GHz. Further, the proposed PIFA is integrated with the class-E power amplifier to design an active-integrated antenna. The simulated results of the active-integrated antenna are presented. It is found that the gain of the active-integrated antenna system is increased from 2.4 dBi (passive) to 17.2 dBi (active).

Design and analysis of an efficient energy harvester using reactance compensation technique for GSM-900

In this paper, impact of diodes nonlinearity on the harvesting circuit performance is studied using LSSP simulation. Based on this study, two reactance compensation techniques are developed for a single band harvesting circuit. These techniques compensate the capacitive reactance of the circuit and thus sustain its resonance for a specific power range (−20dBm to 10dBm). Both circuits have been fabricated and tested. The measured results are compared with simulated results to validate our proposed techniques. A good agreement is obtained. The measured output voltage of the proposed harvesting circuit is found to be 1.5V for an input of −5dBm.

Notice of Violation of IEEE Publication Principles A wideband LNA design based on body bias suitable for low voltage and low power application

A wideband low noise amplifier (LNA) based on body bias technique suitable for low voltage and low power application is presented. Total transconductance of MOS transistor is increased by using body bias technique. Forward body bias (FBB) technique reduces Vth and it solves the problem of low voltage design. In designing LNA, the main concerns are high gain and low noise figure with small return loss. The reported LNA exhibits the best noise and gain performance when compared with existing circuits. The proposed LNA operates in wideband (1-11 GHz) and dissipates power of 19.3 mW from 0.75V supply voltage. The power gain S21, noise figure (NF), input and output reflection coefficients are 10-32 dB, 0.1-1.5 dB, S11 <;-10 dB and S22 <;-15 dB, respectively. A standard 90 nm CMOS process is used for simulation.

A 0.1dB NF, 2GHz low power CMOS low noise amplifier

Short range applications find significant usage in different areas such as industrial process automation and environmental monitoring. Power consumption and noise figure are important constraint for short range application as it carries limited and irreplaceable power sources. This paper describes a CMOS low noise amplifier (LNA) suitable for low voltage short range application. The reported LNA exhibits the best noise performance when compared with existing circuits. The proposed LNA operates at 2 GHz with noise figure (NF) of 0.1 dB, input and output reflection coefficients are S11, S22 <;-10 dB, power gain S21=16 dB and power dissipation of approximately 8 mW from 0.8 V power supply. A standard 90 nm PTM CMOS process is used for simulation.

Calculation of Channel Capacity and Rician Factor in the Presence of Vegetation in Higher Altitude Platforms Communication Systems

Iris-based biometric system is gaining its importance in several applications. However, existing methods of detecting boundary between pupil and iris, which is the first task in any iris-based biometric identification methods are computationally expensive. Further, existing methods are not able to detect pupil boundary accurately and hence leading to errors in identification process. In this paper, we address these two problems and propose a technique to detect pupil boundary efficiently and accurately. We propose scaling and power transform followed by edge detection and circle finding. Scaling reduces the search space significantly and power transform is helpful for image thresholding. Experiments on CASIA iris database reveal that with the proposed approach, we able to detect pupil almost 100% accurately.