Continuous Wave Radar

Continuous Wave Radar

Principle of Operation

        As opposed to pulsed radar systems, continuous wave (CW) radar systems emit electromagnetic radiation at all  times. Conventional CW radar cannot measure range because there is no basis for the measurement of the time delay. Recall that the basic radar system created pulses and used the time interval between transmission and reception to determine the target's range.  If the energy is transmitted continuously then this will not be possible. 

        CW radar can measure the instantaneous rate-of-change in the target's range.  This is accomplished by a direct measurement of the Doppler shift of the returned signal.  The Doppler shift is a change in the frequency of the electromagnetic wave caused by motion of the transmitter, target or both. For example, if the transmitter is moving, the wavelength is reduced by a fraction proportional to the speed it is moving in the direction of propagation.  Since the speed of propagation is a constant, the frequency must increase as the wavelength shortens.  The net result is an upwards shift in the transmitted frequency, called the Doppler shift.



Figure 1. Doppler shift from moving transmitter
Likewise, if the receiver is moving opposite to the direction of propagation, there will a increase in the received frequency. Furthermore, a radar target which is moving will act as both a receiver and transmitter, with a resulting Doppler shift for each. The two effects caused by the motion of the transmitter/receiver and target can be combined into a net shift the frequency. The amount of shift will depend of the combined speed of the transmitter/receiver and the target along the line between them, called the line-of-sight (LOS).

Figure 2. Calculating the relative speed in the line-of-sight.
The Doppler shift can be calculated with knowledge of the transmitter/receiver and target speeds, here designated as s₁ and s₂ respectively, and the angles between their direction of motion and the line-if-sight, designated q₁ and q₂. The combined speed in the line-of-sight is
s = s₁ cosq₁ + s₂ cosq₂ .
This speed can also be interpreted as the instantaneous rate of change in the range, or range rate. As long as the problem is confined to two-dimensions, the angles also have simple interpretations: q₁ = the relative bearing to the target. The difference between the course of the transmitter/receiver and the true bearing to the target. This follows the old nautical rule:
Relative Bearing = True Bearing - Heading
Due to the characteristics of the cosine function, it makes no difference whether angle is positive or negative (strictly speaking, relative bearings are always positive and range from 0 to 359⁰). q₂ = the target angle (relative bearing of transmitter/receiver from target). Computed in an identical manner as the relative bearing, except that the target's course is substituted for the heading and the reciprocal bearing is used instead of the true bearing to the target. The reciprocal bearing is found by:
Reciprocal Bearing = True Bearing 180⁰
Again, it does not matter is this result is positive, negative or even beyond 360⁰, although the proper result would be in the range of 0-359⁰. Assuming that the range rate is known the shift in returned frequency is 
Df = 2s/l

where l is the wavelength of the original signal.   As an example, the Doppler shift in an X-band (10 GHz) CW radar will be about 30 Hz for every 1 mph combined speed in the line-of-sight. 

Example:  speed gun.

 Police often use CW radar to measure the speed of cars.  What is actually measured is the fraction of the total speed which is towards the radar.  If there is some difference between the direction of motion and the line-of-sight, there will be error.  Fortunately for speeders, the measured speed is always lower than the actual.

        CW radar systems are used in military applications where the measuring the range rate is desired.  Of course, range rate can be determined from the basic pulsed radar system by measuring the change in the detected range from  pulse to pulse.  CW systems measure the instantaneous range rate, and maintain continuous contact with the target.

Frequency Modulated Continuous Wave (FMCW) Radar

        It is also possible to use a CW radar system to measure range instead of range rate by frequency modulation, the systematic variation of the transmitted frequency.  What this does in effect is to put a unique "time stamp" on the transmitted wave at every instant.  By measuring the frequency of the return signal, the time delay between

transmission and reception can be measure and therefore the range determined as before.  Of course, the amount of frequency modulation must be significantly greater than the expected Doppler shift or the results will be affected. 

        The simplest way to modulate the wave is to linearly increase the frequency.  In other words, the transmitted frequency will change at a constant rate.



Figure 3. FMCW theory of operation.
The FMCW system measures the instantaneous difference between the transmitted and received frequencies, Df. This difference is directly proportional to the time delay, Dt, which is takes the radar signal to reach the target and return. From this the range can be found using the usual formula, R = cDt/2. The time delay can be found as follows:
Dt = T Df/(f₂-f₁) where:
f₂ = maximum frequency
f₁ = minimum frequency
T = period of sweep from f₁ to f₂,
and Df = the difference between transmitted and received.

There is a slight problem which occurs when the sweep resets the frequency and the frequency difference becomes negative (as shown in the plot of Df vs. time). The system uses a discriminator to clip off the negative signal, leaving only the positive part, which is directly proportional to the range.

Figure 4. FMCW block diagram.

Combining these equations into a single form for the range 

R = 2cTDf/(f₂ - f₁)

where Df is the difference between the transmitted and received frequency (when both are from the same sweep, i.e. when it is positive).

          Another way to construct a FMCW system, is to compare the phase difference between the transmitted and received signals after they have been demodulated to receiver the sweep information.  This system does not have to discriminate the negative values of Df.  In either case however, the maximum unambiguous range will still be determined by the period, namely


R_unamb = cT/2

FMCW systems are often used for radar altimeters, or in radar proximity fuzes for warheads. These systems do not have a minimum range like a pulsed system. However, they are not suitable for long range detection, because the continuous power level they transmit at must be considerably lower than the peak power of a pulsed system. You may recall that the peak and average power in a pulse system were related by the duty cycle,

P_ave = DC *P_peak

For a continuous wave system, the duty cycle is one, or alternatively, the peak power is the same as the average power. In pulsed systems the peak power is many times greater than the average.


http://www.fas.org/man/dod-101/navy/docs/es310/cwradar/cwradar.htm
Christian Argenis Umaña Zambrano
ci :17678077

La telefonía móvil

La telefonía móvil 

se forma básicamente por dos elementos: la red de comunicaciones  y  las terminales. En su versión análoga, fue presentada por primera vez en los Estados  Unidos  en 1946. En ese año el servicio se brindaba en 25 grandes ciudades y  cada ciudad  tenía una estación base que consistía en un  transmisor de alta potencia y  un receptor  colocados  en lo alto de una  montaña  o torre. Este servicio tenía una cobertura de  aproximadamente  30 millas a la redonda. A este primer estándar de telefonía móvil se le  conoció como  MTS   (Mobile Telephone System), y funcionaba con una  comunicación de  tipo half-duplex. Tiempo  después, a principio de los 50 la FCC  duplicó el número  de  canales destinados a la telefonía móvil, reduciéndolos de 120kHz  a 60kHz, con lo que se

 logró una comunicación  full-duplex. Esto último fue la gran ventaja de IMTS  (Improved  Mobile Telephone System) en comparación con su antecesor.

     En  1960 AT&T  presentó la marcación directa. Es necesario mencionar  que antes una  operadora era la que enlazaba las llamadas y que esto representó un gran avance. Tiempo  después, la misma  compañía propuso el concepto celular a la FCC.  A  mediados de los 70  este concepto fue desarrollado en conjunto con minicircuitos integrados capaces de manejar  los complejos algoritmos necesarios para la conmutación  y el control de los canales de

 comunicación. El ancho de banda se redujo de nuevamente de 60kHz a 30kHz.

     En  1974 la FCC   destinó 40MHz   extras del espectro para la telefonía móvil. Un  año  después la FCC  otorgó a AT&T  la primera licencia para operar una telefonía celular en  desarrollo en la ciudad de Chicago. Al otro año, fue ARTS  (American  Radio Telephone Service) la que recibió autorización para operar en Baltimore.

     Sin  embargo,  fue  hasta 1983  cuando  la  telefonía celular comenzó   a  crecer  exponencialmente. Ese  año AMPS   (Advanced Mobile  Phone System) se convirtió en el  primer estándar de telefonía celular. Este estándar originalmente ocupaba 40MHz  de ancho  de banda en la banda de los 800MHz,  pero en 1989 se le otorgaron 166 canales half-duplex  adicionales. Fue en este año que la telefonía celular incursionó en México  por medio de dos  empresas: Iusacell y Telcel.

     En 1991  se comenzaron  a brindar los primeros servicios digitales en la mayor parte de  los Estados Unidos, logrando usar el espectro de una  manera más  eficiente. La  mayor  ventaja de los servicios digitales consistió en la comprensión de voz, lo que dejó espacio en  el ancho de banda asignado para nuevas aplicaciones.

     En  ese momento  de la historia de la telefonía móvil se formaron  dos caminos. La  diferencia entre éstos radicaba en la técnica de acceso múltiple empleada,  fuera TDMA  (Time Division Multiple Access) o CDMA   (Code Divison Multiple Access). En comparación  con  la técnica empleada  por AMPS   u otros estándares de primera  generación, FDMA  (Frequency  Division Multiple Access), las dos ofrecían grandes ventajas. Por ejemplo, la

 capacidad especificada en USDC   (U.S. Digital Cellular) o IS-54 equivale a tres veces la  capacidad de AMPS.

     En  esta segunda generación de telefonía móvil surgieron diferentes estándares, entre  los que destacan: IS-54, IS-95, GSM,  iDEN y PDC.  Con  el tiempo fue GSM  el que logró  mayor  aceptación a nivel mundial, a pesar de que  en sus inicios se concentró en  el  continente Europeo. La mayoría de estos estándares evolucionaron en un paso intermedio  conocido como  2.5G.

     2.5G es utilizado para denominar a los estándares que implementaron conmutación de  paquetes en  sus redes en  conjunto con la conmutación  de circuitos. Mientras que  los  términos 2G y 3G  son reconocidos oficialmente, 2.5G no lo es. Este término fue inventado  simplemente con fines publicitarios y de ventas.

     Un  ejemplo de lo que  es considerado un servicio de 2.5G es GPRS  (General Packet  Switching  Service) implementado   en las redes GSM.   GPRS  emplea  conmutación  de  paquetes para la comunicación de datos, y es por esto que se dice que 2.5G ofrece algunos  servicios de 3G. Otro caso particular de las redes GSM  como  ejemplo de proveedora de  servicios similares a los de 3G es EDGE  (Enhanced  Data Rates for GSM  Evolution), el cual es una tecnología que permite aumentar la tasa de transmisión de datos y su confiabilidad  hasta 236.8 kbit/s.

     En  los primeros  años de  esta década la telefonía móvil evolucionó  hacia otra  generación, 3G. Esta tercera generación ofrece servicios de videoconferencia e Internet de  alta velocidad. A diferencia de 2.5G, 3G  no consiste en mejoras a las redes 2G  y no opera  en el mismo espectro de frecuencia. Es por eso necesario construir nuevas redes y adquirir  nuevas concesiones de frecuencias. El primer país que ofreció 3G  fue Japón. En  2005, 40%  de los suscriptores emplean  solamente redes de tercera generación. Es así que  en 2006  la  transición entre generaciones se completó. Incluso ya se habla de mejoras bajo el nombre  de 3.5G. Estas mejoras incrementaran la máxima  velocidad de 2Mbit/s a 3Mbit/s.

 4.2 Concepto  Celular

     Cuando  la telefonía móvil dejó de tener una sola estación base por red para migrar a la  telefonía celular se corrigieron muchos  problemas. Las claves de este concepto fueron  develadas  en 1947  por investigadores de  los laboratorios Bell y  otras compañías  de  telecomunicaciones alrededor del mundo.  Se  determinó que  si se subdividía un  área  geográfica relativamente grande, llamada zona  de cobertura, en secciones más pequeñas,llamadas  células, el  concepto de  reuso de  frecuencias podrías ser empleado  para  incrementar considerablemente la capacidad del canal.

 4.2.1 Célula

     Una  célula es una zona geográfica de cobertura proporcionada por una estación base.Idealmente se representa por un hexágono  que se une con otros para formar un patrón tipo  enjambre. La  forma hexagonal fue elegida porque provee la transmisión más  efectiva al  aproximarla con una forma  circular y permite unirse a otras sin dejar huecos, lo cual no  hubiera sido posible al elegir un círculo. Una  célula se define por su tamaño físico, pero

 más  importantemente por la cantidad de tráfico y población que existe en ella. El número  de células por sistema no está especificado y depende del proveedor del servicio y de los  patrones de tráfico que observe en su red. El tamaño de la célula varía dependiendo de la  densidad de usuarios. Por ejemplo, en una zona rural se coloca una macrocélula. Este tipo  de célula tiene una cobertura de entre 1 y 15 millas a la redonda con una potencia que varía

 de 1 a 20 watts. Por el contrario, las microcélulas radian de 1 a varios cientos de pies con  potencias de 0.1 a 1 watt. Este tipo de células son frecuentemente usadas en ciudades.

En la Figura 4.1 se puede observar la forma ideal de las células y como están colocadas  adyacentemente. Sin embargo, la forma real de las células no tiene forma. Esto se debe a  los obstáculos que encuentra la señal en el camino,  lo que  depende de cada zona. Las  células ideales se emplean para planificar y dimensionar un sistema considerando un nivel de potencia idéntico para toda el área de cobertura. Esta planificación se vuelve más precisa

 al emplear herramientas de cómputo  que consideran la estructura de la ciudad con edificios,  parques, etc. Un concepto importante al hablar de células es el de hand-off o hand-over.  Este proceso ocurre cuando  el usuario cambia de una célula a otra y el móvil obtiene un  canal sin perder la comunicación. Para saber cuando  debe ocurrir el hand-off se define un umbral  de potencia que generalmente es de -95dBm.  Al momento  de registrar una señal a

 esta potencia el móvil busca otra señal con mejor  potencia en  la célula a la que está  entrando.

    Básicamente  el reuso de frecuencias permite que un gran número  de usuarios puedan  compartir un número limitado de canales disponibles en la región. Esto se logra asignando  el mismo  grupo de frecuencias a más  de una célula. La  condición para que esto se pueda  hacer es la distancia entre ellas, de no hacerlo la interferencia sería alta. A cada estación  base se le asigna un grupo de canales que son diferentes de los de las células vecinas, y las antenas de las estaciones base son elegidas para lograr un patrón de cobertura dentro de la célula por medio de la modificación de parámetros como ganancia y directividad.

     Cuando  se  diseña un sistema usando  células hexagonales, los transmisores de  la  estación base se colocan en el centro de la célula (center-excited cells) o en tres de los seis  vértices (corner-excited cells). Normalmente  se usan antenas omnidireccionales para el  primer caso y antenas sectorizadas para el segundo. Esta sectorización es una forma de  subdividir la célula y lograr mayor  capacidad. Comúnmente   esta división se hace en 3  sectores. Al hacer esto no todo son ventajas. Entre las principales desventajas destacan el  aumento  de equipo de propagación en la estación base, el cambio constante de canales en la  unidad  móvil y la disminución  en truncamiento por la división de canales dentro de la  célula. Aún  así es muy  común  sectorizar la célula, sobretodo en lugares donde la densidad  de población es alta.

 GSM  (Global System for Mobile Communications)

     El servicio de GSM  empezó  en 1991 y en 1993 operaba en 22 países. Actualmente se  tienen este tipo de redes en más de  80 países. GSM  es un  sistema de telefonía celular  perteneciente a la segunda  generación que se desarrolló para solucionar los problemas de  compatibilidad existentes en la primera generación, sobretodo en Europa donde se creó el  estándar. Fue el primer sistema completamente digital y con casi 50 millones de usuarios en

 el mundo se ha convertido en el estándar más popular.

Servicios y arquitectura

     Los  servicios de GSM   se clasifican en tres tipos: bearer services, teleservicios y  servicios suplementarios. Los  primeros  ofrecen la capacidad de transmitir señales entre  puntos de acceso, los segundos permiten comunicarse con otros suscriptores y los últimos  complementan  los teleservicios [15].

     La  arquitectura de una  red GSM   se muestra en Consiste de tres

 subsistemas conectados entre si y con los abonados. Estos sistemas son:

     ¾  BSS (Base Station Subsystem)

     ¾  NSS  (Network and Switching Subsystem)

     ¾  OSS  (Operational Support Subsystem)

http://catarina.udlap.mx/u_dl_a/tales/documentos/lem/nocedal_d_jm/capitulo_4.html#

Christian Argenis umaña Zambrano

ci 17678077

THE WIRELESS TRANSMISSION OF ELECTRICAL ENERGY

In our present electricity generation system we waste

more than half of its resources. Especially the transmission

and distribution losses are the main concern of the present

power technology. Much of this power is wasted during

transmission from power plant generators to the consumer.

The resistance of the wire used in the electrical grid

distribution system causes a loss of 26-30% of the energy

generated. This loss implies that our present system of

electrical distribution is only 70-74% efficient. We have to

think of alternate state - of - art technology to transmit and

distribute the electricity. Now- a- days global scenario has

been changed a lot and there are tremendous development in

every field. If we don't keep pace with the development of

new power technology we have to face a decreasing trend in

the development of power sector. The transmission of power

without wires may be one noble alternative for electricity

transmission

THE TECHNOLOGIES AVAILABLE

In this remarkable discovery of the "True Wireless" and

the principles upon which transmission and reception, even in

the present day systems, are based, Dr. Nikola Tesla shows us

that he is indeed the "Father of the Wireless." The most wellknown

and famous Wardenclyffe Tower (Tesla Tower) was

designed and constructed mainly for wireless transmission of

electrical power, rather than telegraphy [1]. The most popular

concept known is Tesla Theory in which it was firmly

believed that Wardenclyffe (Fig.1) would permit wireless

transmission and reception across large distances with

negligible losses [2]. In spite of this he had made numerous

experiments of high quality to validate his claim of possibility

of wireless transmission of electricity (Fig.2). But this was an

unfortunate incidence that people of that century was not in a

position to recognise his splendid work otherwise today we

may transmit electricity wirelessly and will convert our

mother earth a wonderful adobe full of electricity.

The modern ideas are dominated by microwave power

transmission (MPT, Figure 3) called Solar power satellite to

be built in high earth orbit to collect sunlight and convert that

energy into microwaves, then beamed to a very large antenna

on earth, the microwaves would be converted into

conventional electrical power.

William C. Brown, the leading authority on wireless

power transmission technology, has loaned this demonstration

unit to the Texas Space Grant Consortium to show how power

can be transferred through free space by microwaves. A block

diagram of the demonstration components is shown below.

The primary components include a microwave source, a

transmitting antenna, and a receiving rectenna. 

The microwave source consists of a microwave oven

magnetron with electronics to control the output power. The

output microwave power ranges from 50 W to 200 W at 2.45

GHz. A coaxial cable connects the output of the microwave

source to a coax-to-waveguide adapter. This adapter is

connected to a waveguide ferrite circulator which protects the

microwave source from reflected power. The circulator is

connected to a tuning waveguide section to match the

waveguide impedance to the antenna input impedance.

The slotted waveguide antenna consists of 8 waveguide

sections with 8 slots on each section. These 64 slots radiate

the power uniformly through free space to the rectenna. The

slotted waveguide antenna is ideal for power transmission

because of its high aperture efficiency (> 95%) and high

power handling capability.

A rectifying antenna called a rectenna receives the

transmitted power and converts the microwave power to direct

current (DC) power. This demonstration rectenna consists of 6

rows of dipoles antennas where 8 dipoles belong to each row.

Each row is connected to a rectifying circuit which consists of

low pass filters and a rectifier. The rectifier is a Ga As

Schottky barrier diode that is impedance matched to the

dipoles by a low pass filter. The 6 rectifying diodes are

connected to light bulbs for indicating that the power is

received. The light bulbs also dissipated the received power.

This rectenna has a 25% collection and conversion efficiency,

but rectennas have been tested with greater than 90%

efficiency at 2.45 GHz[4].

The transmission of power without wires is not a theory

or a mere possibility, it is now a reality. The electrical energy

can be economically transmitted without wires to any

terrestrial distance, many researchers have established in

numerous observations, experiments and measurements,

qualitative and quantitative [5-9]. These have demonstrated

that it is practicable to distribute power from a central plant in

unlimited amounts, with a loss not exceeding a small fraction

of one per cent, in the transmission, even to the greatest

distance, twelve thousand miles - to the opposite end of the

globe. This seemingly impossible feat can now be readily

performed by electrical researchers familiar with the design

and construction of my "high-potential magnifying

transmitter," There were three popular theories present in the

literature of the late 1800's and early 1900's. They were:

1. Transmission through or along the Earth,

2. Propagation as a result of terrestrial resonances,

3. Coupling to the ionosphere using propagation through

electrified gases(Fig.4&5)

It has been proven that electrical energy can be

propagated around the world between the surface of the Earth

and the ionosphere at extreme low frequencies in what is

known as the Schumann Cavity. Knowing that a resonant

cavity can be excited and that power can be delivered to that

cavity similar to the methods used in microwave ovens for

home use, it should be possible to resonate and deliver power

via the Schumann Cavity to any point on Earth. This will

result in practical wireless transmission of electrical power.

The intent of the experiments and the laboratory Tesla

had constructed was to prove that wireless transmission of

electrical power was possible. Although Tesla was not able to

commercially market a system to transmit power around the

globe, modern scientific theory and mathematical calculations

support his contention that the wireless propagation of

electrical power is possible and a feasible alternative to the

extensive and costly grid of electrical transmission lines used

today for electrical power distribution.

Power transmission system using directional ultrasound

for power transmission includes a transmitting device and a

receiving device. The transmitting device has a set of

ultrasound transducers forming an ultrasound transducer

array, wherein the array is a set of spaced individual

transducers placed in the X-Y plane disposed to generate an

ultrasound beam in the Z direction (Fig.6) [6].

Another possibility is to use highly efficient fibre lasers

for wireless power transmission where the possibilities are

similar to microwaves concept but lasers emit energy at

frequencies much higher that microwaves.

For several years NASA, ENTECH, and UAH have been

working on various aspects of collection of the laser radiation

and conversion to electrical power for laser wireless power

transmission

III. MERITS, DEMERITS & ECONOMICS OF

WIRELESS TECHNOLOGIES

3.1. Merits

An electrical distribution system, based on this method

would eliminate the need for an inefficient, costly, and capital

intensive grid of cables, towers, and substations. The system

would reduce the cost of electrical energy used by the

consumer and rid the landscape of wires, cables, and

transmission towers.

There are areas of the world where the need for electrical

power exists, yet there is no method for delivering power.

Africa is in need of power to run pumps to tap into the vast

resources of water under the Sahara Desert. Rural areas, such

as those in China, require the electrical power necessary to

bring them into the 20th century and to equal standing with

western nations. The wireless transmission will solve many of

these problems

The electrical energy can be economically transmitted

without wires to any terrestrial distance, so there will be no

transmission and distribution loss.

More efficient energy distribution systems and sources are

needed by both developed and under developed nations. In

regards to the new systems, the market for wireless power

transmission is enormous. It has the potential to become a

multi-billion dollar per year market.

The increasing demand for electrical energy in industrial

nations is well documented. If we include the demand of third

world nations, pushed by their increasing rate of growth, we

could expect an even

Faster rise in the demand for electrical power in the near

future. These systems can only meet these requirements with

90–94 %efficient transmission [3, 8].

High Transmission Integrity and Low Loss: - To transmit

wireless power to any distance without limit. It makes no

difference what the distance is. The efficiency of the

transmission can be as high as 96 or 97 per cent, and there are

practically no losses.

3.2. Demerits

Biological Impact: - One common criticism of the Tesla

wireless power system is regarding its possible biological

effects. Calculating the circulating reactive power, it was

found that the frequency is very small and such a frequency is

very biologically compatible [3, 8].

3.3.Economic Impact

The concept looks to be costly initially. The investment

cost of Tesla Tower was $150,000 (1905). In terms of

economic theory, many countries will benefit from this

service. Only private, dispersed receiving stations will be

needed. Just like television and radio, a single resonant energy

receiver is required, which may eventually be built into

appliances, so no power cord will be necessary! Monthly

electric utility bills from old-fashioned, fossil-fuelled, lossprone

electrified wire-grid delivery services will be optional,

much like "cable TV" of today. In the 21st century, "Direct

TV" is the rage, which is an exact parallel of Tesla's "Direct

Electricity."

IV. ADDITIONAL REMARKS

Many concepts, research papers, patents are available on

wireless transmission of electricity but most research work

were carried out in isolation, so it needs a joint collaborative

efforts to get a very useful results on this advanced technology

on power transmission for the benefit of mankind globally in

future. Whatever the future may bring, the universal 

application of these great principles is fully assured, though it

may be long in coming. With the opening of the first power

plant, incredulity will give way to wonderment, and this to

ingratitude, as ever before.

The world is still not able to achieve the benefit of the

God gifted potential of Dr N.Tesla. People neglected him and

his good work. He deserved much better treatment from the

tycoons of his age, than to spend the last 40 years of his life in

abject poverty. However, he was too much of a gentleman to

hold a grudge. Instead, regarding the magnifying transmitter,

Tesla wrote in his autobiography, "I am unwilling to accord to

some small-minded and jealous individuals the satisfaction of

having thwarted my efforts. These men are to me nothing

more than microbes of a nasty disease. My project was

retarded by laws of nature. The world was not prepared for it.

It was too far ahead of time. But the same laws will prevail in

the end and make it a triumphal success." [3, 8-9]. If this has had

not been happened, then today we will be in a wonder world of

plenty of power using the technology of wireless transmission of

electricity.

V. CONCLUSION

The transmission of power without wires is not a theory

or a mere possibility, it is now a reality. The electrical energy

can be economically transmitted without wires to any

terrestrial distance. Many researchers have established in

numerous observations, experiments and measurements,

qualitative and quantitative. Dr.N.Tesla is the pioneer of this

invention.

Wireless transmission of electricity have tremendous

merits like high transmission integrity and Low Loss (90 – 97

% efficient) and can be transmitted to any where in the globe

and eliminate the need for an inefficient, costly, and capital

intensive grid of cables, towers, and substations. The system

would reduce the cost of electrical energy used by the

consumer and get rid of the landscape of wires, cables, and

transmission towers. It has negligible demerits like reactive

power which was found insignificant and biologically

compatible.

It has a tremendous economic impact to human society.

Many countries will benefit from this service. Monthly

electric utility bills from old-fashioned, fossil-fuelled, lossprone

electrified wire-grid delivery services will be optional,

much like "cable TV" of today.

http://www.tesla-symp06.org/papers/Tesla-Symp06_Mandal.pdf

Christian Argenis Umaña Zambrano

Ci:17678077