Wireless Charging Of Mobile Phones

Wireless Charging Of Mobile Phones Abstract -With mobile phones becoming a basic part of life, the recharging of mobile phone batteries has always been a problem. The mobile phones vary in their talk time and battery standby according to their manufacturer and batteries. All these phones irrespective of their manufacturer and batteries have to be put to recharge after the battery has drained out. The main objective of their manufacturer and battery make. In this paper a new proposal has been made so as to make the recharging of the mobile phones is done automatically as you talk in your mobile phone! This is done by use of microwaves. The microwave signal is transmitted from the transmitter along with the message signal using special kind of antennas called slotted wave guide antenna at a frequency of 2.45GHz. There are minimal additions, which have to be made in the mobile handsets, which are the addition of a sensor, a rectenna and a filter. With the above setup, the need for separate chargers for mobile phones is e liminated and makes charging universal. Thus the more you talk, the more is your mobile phone charged! With this proposal the manufacturers would be able to remove the talk time and battery standby from their phone specifications! INTRODUCTION THE ELECTROMAGNETIC SPECTRUM To start with, to know what a spectrum is: when white light is shone through a prism it is separated out into all the colours of the rainbow; this is the visible spectrum. So white light is a mixture of all colours. Black is NOT a colour; it is what you get when all the light is taken away. Some physicists pretend that light consists of tiny particles which they call photons. They travel at the speed of light (what a surprise). The speed of light is about 300,000,000 meters per second. When they hit something they might bounce off, go right through or get absorbed. What happens depends a bit on how much energy they have. If they bounce off something and then go into your eye you will see the thing they have bounced off. Some things like glass and Perspex will let them go through; these materials are transparent. Black objects absorb the photons so you should not be able to see black things: you will have to think about this one. These poor old physicists get a little bit confused when they try to explain why some photons go through a leaf, some are reflected, and some are absorbed. They say that it is because they have different amounts of energy. Other physicists pretend that light is made of waves. These physicists measure the length of the waves and this helps them to explain what happens when light hits leaves. The light with the longest wavelength (red) is absorbed by the green stuff (chlorophyll) in the leaves. So is the light with the shortest wavelength (blue). In between these two colours there is green light, this is allowed to pass right through or is reflected. (Indigo and violet have shorter wavelengths than blue light.) Well it is easy to explain some of the properties of light by pretending that it is made of tiny particles called photons and it is easy to explain other properties of light by pretending that it is some kind of wave. The visible spectrum is just one small part of the electromagnetic spectrum. These electromagnetic waves are made up of two parts. The first part is an electric field. The second part is a magnetic field. So that is why they are called electromagnetic waves. The two fields are at right angles to each other. THE MICROWAVE REGION Microwave wavelengths range from approximately one millimeter (the thickness of a pencil lead) to thirty centimeter (about twelve inches). In a microwave oven, the radio waves generated are tuned to frequencies that can be absorbed by the food. The food absorbs the energy and gets warmer. The dish holding the food doesnt absorb a significant amount of energy and stays much cooler. Microwaves are emitted from the Earth, from objects such as cars and planes, and from another because microwave energy can penetrate haze, the atmosphere. These microwaves can be detected to give information, such as the temperature of the object that emitted the microwaves. Microwaves have wavelengths that can be measured in centimeter! The longer microwaves, those closer to a foot in length, are the waves which heat our food in a microwave oven. Microwaves are good for transmitting information from one place to light rain and snow, clouds, and smoke. Shorter microwaves are used in remote sensing. These mi crowaves are used for radar like the Doppler radar used in weather forecasts. Microwaves, used for radar, are just a few inches long. Because microwaves can penetrate haze, light rain and snow, clouds and smoke, these waves are good for viewing the Earth from space Microwave waves are used in the communication industry and in the kitchen as a way to cook foods. Microwave radiation is still associated with energy levels that are usually considered harmless except for people with pace makers. Here we are going to use the S band of the Microwave Spectrum. Microwave frequency bands Designation Frequency range K Band 18 to 26 GHz Ka Band 26 to 40 GHz Q Band 30 to 50 GHz U Band 40 to 60 GHz V Band 46 to 56 GHz W Band 56 to 100 GHz L Band 1 to 2 GHz S Band 2 to 4 GHz C Band 4 to 8 GHz X Band 8 to 12 GHz Ku Band 12 to 18 GHz The frequency selection is another important aspect in transmission. Here we have selected the license free 2.45 GHz ISM band for our purpose. The Industrial, Scientific and Medical (ISM) radio bands were originally reserved internationally for non-commercial use of RF electromagnetic fields for industrial, scientific and medical purposes. The ISM bands are defined by the ITU-T in S5.138 and S5.150 of the Radio Regulations. Individual countries use of the bands designated in these sections may differ due to variations in national radio regulations. In recent years they have also been used for license-free error-tolerant communications applications such as wireless LANs and Bluetooth: 900 MHz band (33.3 cm) ( also GSM communication in India )2.45 GHz band (12.2 cm) IEEE 802.11b wireless Ethernet also operates on the 2.45 GHz band. TRANSMITTER DESIGN The MAGNETRON (A), is a self-contained microwave oscillator that operates differently from the linear-beam tubes, such as the TWT and the klystron. View fig(1) is a simplified drawing of the magnetron. CROSSED-ELECTRON and MAGNETIC fields are used in the magnetron to produce the high-power output required in radar and communications equipment. The magnetron is classed as a diode because it has no grid. A magnetic field located in the space between the plate (anode) and the cathode serves as a grid. The plate of a magnetron does not have the same physical appearance as the plate of an ordinary electron tube. Since conventional inductive-capacitive (LC) networks become impractical at microwave frequencies, the plate is fabricated into a cylindrical copper block containing resonant cavities that serve as tuned circuits. The magnetron base differs considerably from the conventional tube base. The magnetron base is short in length and has large diameter leads that are carefully sealed into the tube and shielded. The cathode and filament are at the centre of the tube and are supported by the filament leads. The filament leads are large and rigid enough to keep the cathode and filament structure fixed in position. The output lead is usually a probe or loop extending into one of the tuned cavities and coupled into a waveguide or c oaxial line. The plate structure, shown in fig(1), is a solid block of copper. The cylindrical holes around its circumference are resonant cavities. A narrow slot runs from each cavity into the central portion of the tube dividing the inner structure into as many segments as there are cavities. Alternate segments are strapped together to put the cavities in parallel with regard to the output. The cavities control the output frequency. The straps are circular, metal bands that are placed across the top of the block at the entrance slots to the cavities. Since the cathode must operate at high power, it must be fairly large and must also be able to withstand high operating temperatures. It must also have good emission characteristics, particularly under return bombardment by the electrons. This is because most of the output power is provided by the large number of electrons that are emitted when high-velocity electrons return to strike the cathode. The cathode is indirectly heated and is constructed of a high-emission material. The open space between the plate and the cathode is called the INTERACTION SPACE. In this space the electric and magnetic fields interact to exert force upon the electrons. Fig (1) The magnetron structure RECEIVER DESIGN The basic addition to the mobile phone is going to be the rectenna. A rectenna is a rectifying antenna, a special type of antenna that is used to directly convert microwave energy into DC electricity. Its elements are usually arranged in a mesh pattern, giving it a distinct appearance from most antenna .A simple rectenna can be constructed from a schottky diode placed between antenna dipoles. The diode rectifies the current induced in the antenna by the microwaves. Rectennae are highly efficient at converting microwave energy to electricity. In laboratory environments, efficiencies above 90% have been observed with regularity. Some experimentation has been done with inverse rectennae, converting electricity into microwave energy, but efficiencies are much loweronly in the area of 1%. With the advent of nanotechnology and MEMS the size of these devices can be brought down to molecular level. It has been theorized that similar devices, scaled down to the proportions used in nanotechnology, could be used to convert light into electricity at much greater efficiencies than what is currently possible with solar cells. This type of device is called an optical rectenna. Theoretically, high efficiencies can be maintained as the device shrinks, but experiments funded by the United States National Renewable Energy Laboratory have so far only obtained roughly 1% efficiency while using infrared light. Another important part of our receiver circuitry is a simple sensor. This is simply used to identify when the mobile phone user is talking. As our main objective is to charge the mobile phone with the transmitted microwave after rectifying it by the rectenna, the sensor plays an important role. The whole setup looks something like this. THE PROCESS OF RECTIFICATION Studies on various microwave power rectifier configurations show that a bridge configuration is better than a single diode one. But the dimensions and the cost of that kind of solution do not meet our objective. This study consists in designing and simulating a single diode power rectifier in hybrid technology with improved sensitivity at low power levels. We achieved good matching between simulation results and measurements thanks to the optimisation of the packaging of the Schottky diode. Microwave energy transmitted from space to earth apparently has the potential to provide environmentally clean electric power on a very large scale. The key to improve transmission efficiency is the rectifying circuit. The aim of this study is to make a low cost power rectifier for low and high power levels at a frequency of 2.45 GHz with good efficiency of rectifying operation. The objective also is to increase the detection sensitivity at low levels of power. Different configurations can be used to convert the electromagnetic wave into DC signal, the study done in showed that the use of a bridge is better than a single diode, but the purpose of this study is to achieve a low cost microwave rectifier with single Schottky diode for low and high power levels that has a good performances. This study is divided on two kind of technologies the first is the hybrid technology and the second is the monolithic one. The goal of this investigation is the development of a hybrid microwave recti fier with single Schottky diode. The first study of this circuit is based on the optimization of the rectifier in order to have a good matching of the input impedance at the desired frequency 2.45GHz. Besides, the aim of the second study is the increasing of the detection sensitivity at low levels of power. SENSOR CIRCUITRY The sensor circuitry is a simple circuit, which detects if the mobile phone receives any message signal. This is required, as the phone has to be charged as long as the user is talking. Thus a simple F to V converter would serve our purpose. In India the operating frequency of the mobile phone operators is generally 900MHz or 1800MHz for the GSM system for mobile communication. Thus the usage of simple F to V converters would act as switches to trigger the rectenna circuit to on. A simple yet powerful F to V converter is LM2907. Using LM2907 would greatly serve our purpose. It acts as a switch for triggering the rectenna circuitry. The general block diagram for the LM2907 is given below. Thus on the reception of the signal the sensor circuitry directs the rectenna circuit to ON and the mobile phone begins to charge using the microwave power. CONCLUSION Thus this paper successfully demonstrates a novel method of using the power of the microwave to charge the mobile phones without the use of wired chargers. Thus this method provides great advantage to the mobile phone users to carry their phones anywhere even if the place is devoid of facilities for charging. A novel use of the rectenna and a sensor in a mobile phone could provide a new dimension in the revelation of mobile phone.

Functional Life Skills Approach

1. Educating children with special and/or behavioral needs effectively demands respect for individuals and for individuality. Not all persons with special needs have the same needs. The students come from a variety of backgrounds, demonstrate a variety of talents, strengths, and weaknesses, and must be assessed and worked with on an individual basis. Children with special needs should also be educated alongside their average-needs counterparts, to the benefit of both. When children with average needs are exposed to children with special needs, an atmosphere of tolerance, awareness, and compassion will be more likely to permeate the school environment. Children with special needs also benefit from integration, except in exceptional circumstances when behavioral problems require some degree of separation. Finally, children with special needs require patience and long-term attention. Ideally, children with special needs will work with the same team of specialists for a long period of time. 2. The most important issues to keep in mind when implementing a Functional Life Skills Curriculum Approach include attention to individuality. While the program principles: communication, personal management, social skills, career skills, and applied academics remain stable, these core principles will need to be addressed differently for each child. Moreover, the children's' needs will change over time and it is important for educators to adapt and to notice when their needs or abilities are changing and adapt the curriculum accordingly. 3. Family Support is ideally integral to the educational process. However, in many cases family support is insufficient or lacking entirely. Family support offers educators a wealth of information about each child. The child's background, his or her behaviors at home, and other crucial information can be gleaned only from parents and others who spend a lot of time with the child. The home environment might also offer educators clues as to which programs, services, or practices to offer the child. 4. Outside agencies, organizations, and the private sector have an impact on special education and on the educational process in general. School funding is often inadequate to meet the needs of exceptional students. At those times, educators need to become aware of external options and introduce those to the parents and the students.

Third Battle of Kharkov in World War II

The Third Battle of Kharkov was fought between Feb. 19 and March 15, 1943, during World War II. As the  Battle of Stalingrad  was concluding in early February 1943, Soviet forces launched Operation Star. Conducted by Colonel General Filipp Golikovs Voronezh Front, the goals of the operation were the capture of Kursk and Kharkov. Spearheaded by four tank corps under Lieutenant-General Markian Popov, the Soviet offensive initially met with success and drove back German forces. On Feb. 16, Soviet troops liberated Kharkov. Angered by the loss of the city, Adolf Hitler flew to the front to assess the situation and meet with the commander of Army Group South, Field Marshal Erich von Manstein. Though he desired an immediate counterattack to re-take Kharkov, Hitler ceded control to von Manstein when Soviet troops neared Army Group Souths headquarters. Unwilling to launch a direct assault against the Soviets, the German commander planned a counterstroke against the Soviet flank once they became overextended. For the coming battle, he intended to isolate and destroy the Soviet spearheads before mounting a campaign to re-take Kharkov. This done, Army Group South would coordinate with Army Group Center to the north in re-taking Kursk. Commanders Soviet Union Colonel General Konstantin RokossovskyColonel General Nickolay VatutinColonel General Filipp Golikov Germany Field Marshal Erich von MansteinGeneral Paul HausserGeneral Eberhard von MackensenGeneral Hermann Hoth The Battle Begins Commencing operations on February 19, von Manstein directed General Paul Haussers SS Panzer Corps to strike south as a screening force for a larger assault by General Hermann Hoths Fourth Panzer Army. Hoths command and General Eberhard von Mackensens First Panzer Army were ordered to attack into the overextended flank of the Soviet 6th and 1st Guards Armies. Meeting with success, the early days of the offensive saw German troops breakthrough and sever Soviet supply lines. On February 24, von Mackensens men succeeded in surrounding a large part of Popovs Mobile Group. German troops also succeeded in surrounding a large portion of the Soviet 6th Army. Responding to the crisis, the Soviet high command (Stavka) began directing reinforcements to the area. Also, on February 25, Colonel General Konstantin Rokossovsky launched a major offensive with his Central Front against the junction of Army Groups South and Center. Though his men had some success on the flanks, going in the center of the advance was slow. As the fighting progressed, the southern flank was halted by the Germans while the northern flank began to overextend itself. With the Germans exerting heavy pressure on Colonel General Nikolai F. Vatutins Southwestern Front, Stavka transferred 3th Tank Army to his command. Attacking the Germans on March 3, this force took heavy losses from enemy air attacks. In the resulting fighting, its 15th Tank Corps was encircled while its 12th Tank Corps was compelled to retreat north. The German successes early in the battle opened a large gap in the Soviet lines through which von Manstein pushed his offensive against Kharkov. By March 5, elements of Fourth Panzer Army were within 10 miles of the city. Striking at Kharkov Though concerned about the approaching spring thaw, von Manstein pushed toward Kharkov. Rather than advance to the east of the city, he ordered his men to move to the west then north to encircle it. On March 8, SS Panzer Corps completed its drive north, splitting the Soviet 69th and 40th Armies before turning east the next day. In place on March 10, Hausser received orders from Hoth to take the city as soon as possible. Though von Manstein and Hoth wished him to continue the encirclement, Hausser directly attacked Kharkov from the north and west on March 11. Pressing into northern Kharkov, the Leibstandarte SS Panzer Division met heavy resistance and only gained a foothold in the city with the aid of air support. The Das Reich SS Panzer Division attacked into the western side of the city the same day. Stopped by a deep anti-tank ditch, they breached it that night and pushed on to the Kharkov train station. Late that night, Hoth finally succeeded in making Hausser comply with his orders and this division disengaged and moved to blocking positions east of the city. On March 12, Leibstandarte division renewed its attack south. Over the next two days, it endured brutal urban fighting as German troops cleared the city house-by-house. By the night of March 13/14, German troops controlled two-thirds of Kharkov. Attacking again the next, they secured the remainder of the city. Though the battle largely concluded on March 14, some fighting continued on the 15th and 16th as German forces expelled Soviet defenders from a factory complex in the south. The Aftermath of the Third Battle of Kharkov Dubbed the Donets Campaign by the Germans, the Third Battle of Kharkov saw them shatter fifty-two Soviet divisions while inflicting approximately 45,300 killed/missing and 41,200 wounded. Pushing out from the Kharkov, von Mansteins forces drove northeast and secured Belgorod on March 18. With his men exhausted and the weather turning against him, von Manstein was compelled to call a halt to offensive operations. As a result, he was unable to press on to Kursk as he had originally intended. The German victory at the Third Battle of Kharkov set the stage for the massive Battle of Kursk that summer. Sources World War II Database: Third Battle of KharkovTimelines: Third Battle of KharkovHistory of War: Third Battle of Kharkov

Events Causes And Consequences Of President Ronald Reagan

†¢ Event Name Type of Event Causes Course Consequences 1980 Election This was a political event because it caused a change in the government. Americans wanted a firm, patriotic leader who had a plan to fix the economic problems carrying over from the 1970s. Jimmy Carter was running for reelection, and Americans overall were very unhappy with his leadership. Ronald Reagan emerged as his challenger, a former actor with great public skills and a plan. They elected Ronald Reagan in 1980 who had a controversial plan for fixing the U.S. economy, later dubbed â€Å"Reaganomics.† 1980 Regan’s Plan The economy focused on cutting taxes, reducing the size of government, and eliminating controls over certain business, called deregulation. It relaxed rules in banking and savings and loan industries to help encourage loans for people to buy houses and start businesses. The idea behind the plan was to put more money in the pockets of people and businesses so they would purchase more things, increase innovation, reduce unemployment, and lower inflation. Reagan increased defense spending. U.S. exports were falling, creating a negative balance of trade where the country was buying more from foreign countries than it was selling to them. 1980 Regan Doctrine This was the president s foreign policy in the 1980s of supporting anti-Communist revolutions through the Cold War. 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