RF-Based Wireless Charging and Energy Harvesting - Coursework Example

WIRELESS RF ENERGY HARVESTER By RF-based Wireless Charging and Energy Harvesting is a process based on modern technologies and aids in improving the design of the product. The technology is currently used in broadcasting several transmitters of radios in the entire world. It is used in hand-held radios, mobile phones, radio and television broadcasting stations as well as mobile base stations among others. The application is capable of allowing the charging of wireless devices through dedicated or ambient sources. In this paper, I am going to discuss about my final project that will consist the design of Rectenna by using the OrCAD Capture CIS Lite for the simulation of the circuit. Contents Abstract 2 Contents 3 INTRODUCTION 4 Background of RF Energy Harvester 4 Aims and objectives of the Project 5 Structure of the report 5 Reason for choosing the Project 6 HARVESTING PROCESS (CIRCUIT) 6 CIRCUIT SIMULATION 8 LITERATURE REVIEW OF THE PROJECT 9 PLANNING 12 References 15 INTRODUCTION Background of RF Energy Harvester The designing of Rectena device is undertaken via the use of OrCAD Capture CIS Lite process. Rectena is a device that is capable of using capturing microwave by using power supply that is wireless and then converts the power to DC in order to produce other related devices or circuits that are placed on a chip. OrCAD capture is a device with schematic solutions that can generate and document electric circuits. Placed together with the OrCAD CIS it can be seen to be a powerful tool of designing environment in generating the current worlds products generation to production from concepts. The project uses Capture CIS that almost looks alike with the OrCAD tool. The function of the CIS (Component Information System) is to link the component information with the symbol of the circuit found in the schematic. Components information linked includes printed circuit board, simulation behavior data as well as package footprint data among others. The transfer of information from CIS usually happens to the OrCAD design tool. This can lead to most of the circuit elements being linked to the footprints especially when schematic tools are exported to the circuit board layout. Through Capture CIS, a simulation configuration file can be exported and the simulation toolbar can allow for its accessibility. Netlists can also be exported by the CIS Capture which is open simulation utility of the OrCAD (PSpice). The currently opened hardware description that is either in Verilog or VHDL can also be exported by the Capture. Netlists from various layouts utilities can also be exported by Capture, and they include OrCAD layout, Allegro among others. Circuit board footprints can also be linked to these netlist especially when combined with CIS. This are the features that can make the simulation and design of Rectena easier (MASUD p55 2013). However, there are various problems associated with the design of Rectenna. The first problem is that it can be impossible in designing a rectenna capable of producing an intensity enhancement of a maximum near field. Another problem is the incapability of designing and fabrication of a THZ Rectenna which has a higher efficiency of converting high AC to DC that also needs to benefit from the enhancement of the filed by placing it on a hot spot. Finally, the third problem encountered is the production of a match of good impedance between the antenna and the Rectenna through lowering Rectenna’s high resistance (Masud, 2013, pp.167-189). Aims and objectives of the Project The design of Rectenna’s is majorly conducted to design the Rectenna that is capable of rectifying the incoming electromagnetic waves into Direct Current power (DC). This will consequently aids in designing of wireless power transmissions and the transmission of space solar power. The project aims at designing a Rectenna based on communication and detection, which will be capable of working in terahertz and can brig the gap between the modern and traditional Rectennas. With their high speed, they can also be used in transmitting data that travels at high speeds since there will be several terahertz of communication bandwidth. Designing of a Terahertz Rectenna is based on imaging. Design of an imager works approximately between a terahertz of 4 and 32 THz and is applicable in night imaging utilizing the infrared goggles and cameras. Structure of the report The report starts from by giving brief background of the wire RF energy harvester using OrCAD Capture CIS Lite coupled with the Rectena, which converts the power to DC, which produce other related devices within the chip. This encompasses outlining of all the aims and objectives and the reason for choosing the project. Throughout the tasks, which were, completed tested Thermoelectric Generator was utilized in determining the capacities of the quantity of cooling required and the corresponding loading. This was followed by analysis of the Simulation results and programing and debugging microcontroller in order to monitor voltage levels. The body of the report will give detailed information concerning harvesting process, simulation process, detailed literature review and the work plan of the entire report. The report will be crowned by giving brief conclusion of the topic and its underlying uses. Reason for choosing the Project Being an engineer, I saw it interesting in conducting this project so that I could use the application of Rectenna in coming up with new innovations and products. I prefer on creating new cameras as well goggles that will use this application for the transmission of data. Also am interested in the project mainly because to harness the power energy into Direct Current energy commonly used. I also prefer in creating cost-effective Rectennas that will be affordable to most people so that majority could enjoy the benefits of this products. HARVESTING PROCESS (CIRCUIT) Because energy harvesting circuit entails diodes, which are normally nonlinear devices thus making the circuit to exhibits nonlinearity. This depicts that the prevailing impedance of the energy harvesting circuit fluctuates with the existing amount of power received from the corresponding antenna. Moreover, since the underlying maximum power transfer occurs when the circuit matched with the underlying antenna, the resultant impedance matching is normally undertaken at certain input power. The impedance matching network undertakes impedance transformation to ensure that there is maximum power delivery. The matching circuit functions at 950MHz and corresponding input impedance of 50Ω coupled with the load resistance of 100k Ω. Figure 1. Matching circuit Harvesting wireless energy using Rectennas has proven to be the most successful method ever. The Rectenna combines the antenna and a rectifier. The paper will mainly present wireless delivery approach in power delivery for sensors that uses low power and uses no battery. The two orthogonal wave polarizations that are rectified and received by Rectenna arrays of Broadband multifrequency are responsible for providing DC power within a multipath environment and characterized with decreased variations (Priya & Inman, 2008, pp.145-178). There is a high power processing circuit that manage the DC power generated from the 2-19 GHz electromagnetic Radiation. The Rectenna is composed of a receiving antenna and a circuit responsible for rectification. Through these devices, a DC power can be generated from a microwave or RF power. The antenna will receive incident waves that are that are within the range of certain spectra. These waves are then coupled to either a rectifying device that can be diode or any other rectifying device. There is also Low-Pass filter that will ensure that the circuit of power management does not allow any RF into it. Power management circuit will receive inputs through the control of a controller and thereby enabling for the storage of received power for a given period. The power management circuit is also responsible for the delivery of Direct Power whenever it is required. The low-pass filter is also responsible for blocking the harmonics of the high order that are produced by the diode. This will allow for the achievement of the most important parameter known as high-energy conversion efficiency (Priya & Inman, 2008, pp.123-189).  There are narrow-band and wide-band Rectennas. The most desirable Rectannas for the harvesting of wireless energy are the few broadband rectennas. This rectannas are capable of generating energy from systems that usually operates at different frequencies in order to generate or have a maximum power at various locations. Nevertheless, to generate the maximum power needed, there must be a match with rectifier diode and the antenna impedance. On the other hand, to generate a varying input power, then there must be a quantification of resultant DC for every source impedance. The optimal source region is the one responsible for optimizing the design of antenna required for the matching of the diode impedance. CIRCUIT SIMULATION The characteristics of the voltage doubler rectifier based RF energy harvesting circuit by simulated graphs. These underlying characteristics are mainly categorized in three parts. The first part depicts the effect of Grainacher voltage-doubler circuit on the input and out voltage whilst the part depicts effect of different load resistance values on output dc power. The final part depends on the selected load the output dc power against received RF power characteristics. a. Effect of Voltage-Doubler Rectifier The input voltage characteristics curve across the capacitor C2 depicts the input voltage level escalates gradually with respect to the escalation the received incident RF power. Same input power level depicts the output voltage across the capacitor C3, which is twice the output power. Depending on the received on the input power, the input voltage is mainly varied from the lowest 0.3V to highest 1.0V. b. Effect of load resistance In measuring the output dc power, a resistive load is attached parallel to capacitor C3 since without any resistive load no current cannot be drawn at the output terminal. To measure the output dc power characteristics against the altering of load resistance R1. Four fixed values from sweeping parameter of input RF power are -15dBm, -10dBm, -5dBm and 0 dBm. The parameter of the load resistance is swept from 1Ω to 10 K Ω. For the -5dBm the harvested dc power has been reached to the maximum value of the output dc power is the microwatt range. Moreover, the average harvested dc power will be optimum in case there 5K Ω load to output terminal of the rectifier circuit. c. Output dc Power Characteristics at Selected Load After selection of the resistive load of 5K Ω output dc power characteristics with respect to the input RF power. Harvested power increases slowly as the underlying received RF power escalates. For the received RF power varying from the -15dBm to corresponding 0 dBm, the output dc power fluctuates from 9. 2uW to 356.5uW (Priya & Inman, 2008, pp.145-178) LITERATURE REVIEW OF THE PROJECT RF wireless powering is an energy harvesting method that entails the use of an inductive connection amidst tow resonant systems. An external electrical power source is utilized to propel a primary coil loop, which coupled RF energy into corresponding secondary loop via magnetic coupling (Masud, 2013, pp. 178-199). This is very different from the corresponding inductive based vibration energy harvesting method, which normally converts mechanical energy imposed on a magnet moving via a coil into the underlying electrical current. RF wireless powering has become imminent due to its advanced application encompassing embedded biomedical systems for the vivo diagnostic devices. These devices have secondary coil implanted in human tissue and receives the RF power from corresponding external coil. Wireless energy powering transmission takes place through electromagnetic waves for the RF radiation. The concept uses two diverse RF energy sources namely the ambient and controlled RF sources. This depicts that the underlying electronics could effectively capture ambient RF radiation and converts them to fundamental electricity. According to Priya and Inman (2008), the charge of cellular phone battery takes place via collection of ambient 915MHz RF energy. Electronics with the ultra-low power consumption might be propelled through this approach, but the quantity of harvested power is very low, ideally in the range of a few microwatts. Thus, the method received the fundamental attention is the controlled RF sources. The approach of controlled RF sources is mainly based on the RF connection, which encompasses of primary and corresponding secondary coils. When the prevailing two coils are close to every other and well centered-aligned, the input AC power is wirelessly transferred from primary coil to the corresponding secondary coil through the inductive connection (Masud, 2013, pp. 178-199). Another controlled microwave transmission is the beamed RF sources, which is a source antenna microwaves across the prevailing atmosphere or corresponding space to the underlying receiver. The receiver can either be a typical antenna having a rectifying circuitry to convert the microwaves to the DC power or antenna that mainly assimilates the technology to receive and directly convert the microwaves into the DC conversion accomplishment. The usage of rectennas efficiencies is in the range of 50% to 80% for DC to the DC conversion accomplishment. Important testing is undertaken across long distance and with the underlying kW power levels, a RF wireless energy distribution system for the underground gas or oil recovery pipes (Masud, 2013, pp. 178-199). RF energy generation occurs on the surface then travel via the conductive pipe that acts as an antenna or waveguide. The sensor module within the bottom of the pipe captured the energy and powered the underlying electrical equipment Comparison of Power Density of Energy Harvesting Methods Energy Source Power Density & Performance Sources of information Acoustic Noise 0.003 μW/cm3 @ 75Db 0.96 μW/cm3 @ 100Db Rabaey, Ammer, Da Silva Jr, Patel, & Roundy, 2000) Temperature Variation 10 μW/cm3 (Roundy, Steingart, Fréchette, Wright, Rabaey, 2004) Ambient Radio Frequency 1 μW/cm2 (Yeatman, 2004) Ambient Light 100 mW/cm2 (direct sun)  100 _W/cm2 (illuminated office) Available Thermoelectric 60 _W/cm2 (Stevens, 1999) Vibration  (micro generator) 4 _W/cm3 (human motion Hz)  800 _W/cm3 (machines kHz) (Mitcheson, Green, Yeatman,  & Holmes, 2004) Vibrations (Piezoelectric) 200 μW/cm3 (Roundy, Wright, & Pister, 2002) Airflow 1 μW/cm2 (Holmes, 2004) Push buttons 50 _J/N (Paradiso & Feldmeier, 2001) Shoe Inserts 330 μW/cm2 (Shenck & Paradiso, 2001) Hand generators 30 W/kg (Starner & Paradiso, 2004) Heel strike 7 W/cm2 (Yaglioglu, 2002)  (Shenck & Paradiso, 2001) Nevertheless, the table does not comprehensively give large range of potentials that can be utilized in harvesting energy via the use of ambient energy sources. It depicts that lights is an important sources of light even though it still largely depend on the experience and applications of the underlying devices. Due to the differences of temperature variations across the chip, thermal energy is perceived to be limited ( Priya & Inman, 2008, pp. 256-267). According to Torres and Rincon-Mora (2005) research, the variation of energy alone cannot generate much energy as it rely on particular applications. PLANNING Planning of the project is the most important part of this specific project requires the use of “Planning Gantt Chart” that will indicate the progress of the selected project. Project Planning using Gannt Chat First, the project plan is to draft a listing down every requirement in the plan. The drafted plan will run from November 10, 2014 to January 20, 2014. The plans entail research on more circuits, comparison of the underlying circuits, improvements of the circuits, ordering of the existing parts of circuits, going for Christmas vacation, building of the circuit, testing the circuit and documentation of the whole circuit. The first ten days from November 10 to November 20 will be undertaking more research on the underlying circuits to determine their feasibility and viability. This will helps in determining various circuits that exist and their advantages and disadvantages regarding the present design. This will be followed by comparison of the existing circuits concerning their functionality, merits, demerits, reliability, cost and usability and it will take places from 20th November to 30th November. Comparison of the circuits will enable choosing of appropriate circuit that will be design for wireless RF energy harvester. Planning entails a comparison of the best places to purchase the best and in good quality devices. Improvement of the circuit will mainly focus on the purchases of software and hardware devices for harvesting energy from ambient sources. It will purely entail purchase of the device in the month of November that is from 30th November to 10th December. Ordering of the parts of the suitable selected circuit will takes place between 10th December to 20th December. This is entail installation and wiring of the circuit device to ensure effective operation devoid of compromising quality of the results. At this stage, there will be proper analysis of the Rectinna device suitable for the project. This will be followed by Christmas vacation for ten days. Thus, the project will be embarked on 9th January 2015. The final phase of developing the project is building and testing of the circuit. This is the section that that should eliminate every fault in the device and come up with innovations to use to make it better. The development part should also include assembling of the spare parts for the device just in case there might be a problem, and then the spare parts to be used as an alternative. The design will be tested to know their functionality and suitability, which will take place between 9th to 19th January 2015. After testing and ensuring that, the design circuit is properly functioning and reliability, documentation of the whole design will be undertaken. Documentation is the assembly of the whole design project of the wireless RF energy harvester having appropriate parts and properly functioning. CONCLUSION Harvesting energy can be performed by the use of several external sources including thermal energy, wind energy, gradients of salinity among others. The energy is captured and stored for devices that are extremely small such as those used in wireless sensor networks as well as wearable electronics. In addition, there is very low power for electronics that uses energy from the Energy harvesters, the only source present for energy is the ambient or environmental source and is naturally free. For instance, the gradient of temperature exists in the engines of combustions as well in towns or urban centers. The presence of radio and television broadcasting has led to the increase of electromagnetic energy in the environment. References Priya, S., & Inman, D. J. (2008). Energy harvesting technologies. New York, Springer. http://public.eblib.com/choice/publicfullrecord.aspx?p=417906 Penella-López, M. T., & Gasulla Forner, M. (2011). Powering autonomous sensors: an integral approach with focus on solar and RF energy harvesting. Dordrecht [Netherlands], Springer. Beeby, S., & White, N. (2010). Energy harvesting for autonomous systems. Norwood, MA, Artech House. Gwuogo, J. (2012). On-demand energy harvesting techniques - a system level perspective. Waterloo, Ont, University of Waterloo. Masud, P. M. (2013). A methodology for designing 2.45 GHz wireless rectenna system utilizing dickson charge pump with optimized power efficiency. Waterloo, Ont, University of Waterloo. Read More