GUIDED BY: PREPARED BY:

Prof. J.B.Chaudhri Vijay Yadav (140403111014)

Ravi chaudhri(140403111016)

Sankalchand Patel collage of engineering

Subject : microwave engineering Subjectcode2171001

microwave systems

Content

Wireless communication .

radar systems.

satellite systems

Microwave Antenna

Wireless communication

Wireless communication is the transfer of information or power between two or more

points that are not connected by an electrical conductor.

The most common wireless technologies use radio .

With radio waves distances can be short, such as a few meters for television or as far

as thousands or even millions of kilometers for deep-space radio communications.

It encompasses various types of fixed, mobile, and portable applications, including

two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless

networking.

Other examples of applications of radio wireless technology include

GPS units,

garage door openers.

wireless computer mice.

5

Analog RF systemDigital RF system

Microwave Systems

Microwave communication is line of sight radio

communication For directive antennas, or broadcasting with

omi-directional antennas.

Radio Transmission: the speech signals are converted to EM Power is

transmitted in space towards destination EM waves are intercepted by

receiving antennas and signal power is collected.

Radar Systems.

Radar is an object-detection system that uses radar waves to determine

the range, angle, or velocity of objects. It can be used to detect aircraft,

ships, spacecraft, guided missiles , motor vehicle , weather formations,

and terrain.

A radar system consists of a transmitter producing electromagnetic waves

in the radio or microwaves domain, an emitting antenna, a receiving

antenna (separate or the same as the previous one) to capture any returns

from objects in the path of the emitted signal, a receiver and processor to

determine properties of the object(s).

The modern uses of radar are highly

diverse, including air and terrestrial

traffic control, radar astronomy , air

defense systems , antimissile systems ,

marine radars to locate landmarks and

other ships, aircraft anti-collision

systems, ocean surveillance systems,

outer space surveillance and rendezvous

systems, meteorological precipitation

monitoring.

High tech radar systems are associated

with digital signal processing , machine

learning and are capable of extracting

useful information from very high noise

levels.

applications of microwave radio.

Microwave Antenna

Antennas used can be:

• Omni-directional-in this case radio power is transmitted

Uniformly in all directions

Such type of antenna are preferred where uniform coverage

is desired such as in cellular systems.

• Directional: in case of UHF communication.

• Highly directional: in case of microwave communications,

microwave signals are transmitted in very narrow beam.

Normally 3 M Diameter Antenna at 2 GHz BW has half power

of about 3.4 degrees beam width.

Adaptive Beam Forming

There are two kinds of adaptive antennas: switched beam arrays and

adaptive arrays.

Both switched beam arrays and adaptive arrays are being employed in

some cell phone systems and in newer wireless LANs.

They are particularly beneficial to cell phone systems because they

can boost the system capacity.

• Remote sensing is the science and art of acquiring information about an object, area or phenomena without actually being in contact with it.

• The sensor is usually mounted on moving platforms such as balloons, aircraft and satellites

• Platforms of remote sensing are:

– Land based (surface or ground observation)

– Airborne based (from 100 m to 40 km)

– Space based (from 150 km to 36000 km)

satellite

Two Stations on Earth want to communicate through radio broadcast but are

too far away to use conventional means.

The two stations can use a satellite as a relay station for their communication

One Earth Station sends a transmission to the satellite.

This is called a Uplink.The satellite Transponder converts the signal and

sends it down to the second earth station. This is called a Downlink.

Advantages of Satellites

The advantages of satellite communication over terrestrial communication are:

The coverage area of a satellite greatly exceeds that of a terrestrial system.

Transmission cost of a satellite is independent of the distance from the center of the coverage area.

Satellite to Satellite communication is very precise.

Higher Bandwidths are available for use.

• The disadvantages of satellite communication:

Launching satellites into orbit is costly.

Satellite bandwidth is gradually becoming used up.

There is a larger propagation delay in satellite communication than in

terrestrial communication.

Disadvantages of Satellites

• Satellite Orbits

GEO

LEO

MEO

Molniya Orbit

HAPs

• Frequency Bands

Types of Satellites

Reference

www.google.com

www.wikipedia.com

Reface book

samuel liao- microwave devices and circuit,

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