3. INTRODUCTION
Microwave is a form of electromagnetic radiation with wavelengths ranging from
about one meter to one millimeter corresponding to frequencies between 300 MHz
and 300 GHz respectively. Different sources define different frequency ranges as
microwaves; the above broad definition includes both UHF and EHF (millimeter
wave) bands. A more common definition in radio-frequency engineering is the
range between 1 and 100 GHz (wavelengths between 0.3 m and 3 mm).[2] In all
cases, microwaves include the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at
minimum. Frequencies in the microwave range are often referred to by their IEEE
radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU
designations.
4. USES OF MICROWAVES
COMMUNICATION
REMOTE SENSING
BIOMEDICAL
NAVIGATION
POWER
THERE ARE LOTS OF APPLICATIONS OF MICROWAVES, LIKE IN THE
FIELD OF-
MICROWAVE IMAGING, PHOTO-ACOUSTIC IMAGING IN BIOMEDICINE.
THERMOTHERAPY, LASER THERAPY FOR CANCER CELL TREATMENT.
GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS) INCLUDING THE AMERICAN GLOBAL POSITIONING SYSTEM (GPS) AND
THE RUSSIAN
GLONASS BROADCAST NAVIGATIONAL SIGNALS IN VARIOUS BANDS BETWEEN
ABOUT 1.2 GHZ AND 1.6 GHZ.
A MICROWAVE PASSES (NON-IONIZING) MICROWAVE RADIATION (AT
A FRE
5. WHAT IS
COMMUNICATION?
THE TRANSFER OF INFORMATION IS THE STANDARD DEFINITION OF
COMMUNICATION. THE PHRASE CAN EITHER BE USED TO DESCRIBE THE
ACTUAL MESSAGE OR THE AREA OF STUDY THAT EXAMINES THESE
TRANSMISSIONS, KNOWN AS COMMUNICATION STUDIES. THERE ARE
SOME DIFFERENCES OF OPINION REGARDING THE EXACT DEFINITION OF
COMMUNICATION, SUCH AS WHETHER ACCIDENTAL OR FAILED
TRANSMISSIONS ARE INCLUDED AND IF COMMUNICATION CREATES
MEANING IN ADDITION TO TRANSMITTING IT. COMMUNICATION MODELS
SEEK TO GIVE A CONCISE OVERVIEW OF ITS KEY ELEMENTS AND HOW
THEY WORK TOGETHER. MANY MODELS INCORPORATE THE NOTION
THAT A SOURCE USE A CODING SCHEME TO CONVEY INFORMATION AS A
MESSAGE. THE MESSAGE IS TRANSMITTED FROM THE SOURCE TO THE
RECEIVER VIA A CHANNEL, WHO MUST DECODE IT TO COMPREHEND
WHAT IT MEANS.
6. USES OF MICROWAVES
IN COMMUNICATION
DUE TO THEIR SHORT WAVELENGTH AND ABILITY TO BE FOCUSED INTO
NARROW BEAMS THAT MAY BE TARGETED DIRECTLY AT THE RECEIVING
ANTENNA, MICROWAVES ARE FREQUENTLY UTILISED FOR POINT-TO-POINT
COMMUNICATIONS. LIKE A RESULT, NEIGHBOURING MICROWAVE EQUIPMENT
CAN OPERATE ON THE SAME FREQUENCIES WITHOUT INTERFERING WITH ONE
ANOTHER LIKE LOWER FREQUENCY RADIO WAVES CAN. BY REUSING
FREQUENCIES, RADIO SPECTRUM BANDWIDTH, WHICH IS LIMITED, IS
PRESERVED. ANOTHER BENEFIT IS THAT THE MICROWAVE BAND HAS A VERY
HIGH INFORMATION-CARRYING CAPACITY DUE TO ITS HIGH FREQUENCY; IT
HAS A BANDWIDTH THAT IS 30 TIMES GREATER THAN THE REMAINDER OF THE
RADIO SPECTRUM BELOW IT. THE FACT THAT MICROWAVES CAN ONLY TRAVEL
IN A STRAIGHT PATH, UNLIKE LOWER FREQUENCY RADIO WAVES, POSES A
DRAWBACK.
DEEP SPACE RADIO COMMUNICATIONS, SATELLITE COMMUNICATIONS, AND
POINT-TO-POINT COMMUNICATION NETWORKS ALL FREQUENTLY USE
MICROWAVE RADIO TRANSMISSION. RADARS, RADIO NAVIGATION SYSTEMS,
SENSOR SYSTEMS, AND RADIO ASTRONOMY ALL EMPLOY DIFFERENT
7. USE OF MICROWAVES IN
COMMUNICATION
THE SHORT PHYSICAL WAVELENGTH OF THESE FREQUENCIES, THEY
PRESENT SEVERAL UNIQUE FEATURES. HENCE, THEY ARE SUITABLE FOR
VARIOUS UNIQUE AND SPECIFIC APPLICATIONS, STARTING FROM SHORT-
DISTANCE TO LONG-DISTANCE COMMUNICATION, FROM DETECTING A
TARGET AT A SHORT DISTANCE TO IDENTIFYING START LIGHT-YEARS
AWAY FROM IDENTIFYING A SMALL OBJECT TO MAPPING THE SURFACE OF
A PLANET, FROM THE STUDY OF A LINEAR PARTICLE ACCELERATOR TO
THAT OF PLASMA, FROM DOMESTIC COOKING TO INDUSTRIAL HEATING
AND MANY MORE.
8. TELEVISION AND RADIO BROADCASTING
CELLULAR NETWORKS
WI-FI NETWORKS
SATELLITE COMMUNICATION
MILITARY COMMUNICATION
WEATHER FORECASTING AND MONITORING
NAVIGATION AND GPS SYSTEMS
MICROWAVE COMMUNICATION IS USED IN A VARIETY
OF APPLICATIONS, INCLUDING:
Applications of microwave
communication
9. BEFORE THE ADVENT OF FIBER OPTIC TRANSMISSION, MOST LONG-
DISTANCE TELEPHONE CALLS WERE WELL CARRIED VIA MICROWAVE
POINT-TO-POINT LINKS THROUGH SITES LIKE THE AT&T LONG LINES.
STARTING IN THE EARLY 1950’S FREQUENCY WAS USED TO SEND UP TO
5,400 TELEPHONE CHANNELS ON EACH MICROWAVE RADIO CHANNEL
COMBINED INTO ONE ANTENNA OR THE HOP TO THE NEXT SITE, UP TO
70 KM AWAY.
WIRELESS LAN PROTOCOLS, SUCH AS BLUETOOTH AND THE IEEE 802.11
SPECIFICATIONS, ALSO USE THE MICROWAVE IN THE 2.4 GHZ ISM BAND,
ALTHOUGH 8.2.11A USES THE ISM BAND AND U-NII FREQUENCIES IN THE
5 GHZ RANGE. LICENSED LONG-RANGE (UP TO ABOUT 25 KM). WIRELESS
INTERNET ACCESS SERVICES CAN BE FOUND IN MANY COUNTRIES IN
THE 3.5 – 4.0 GHZ RANGE.
METROPOLITAN AREA NETWORKS: MAN PROTOCOLS, SUCH AS WIMAX
(WORLDWIDE INTEROPERABILITY FOR MICROWAVE ACCESS) BASED ON
THE IEEE 8.2.16 SPECIFICATION. THE IEEE 8.2.16 SPECIFICATION WAS
1.
2.
3.
10. Advantages of Microwave
Communication
FOLLOWING ARE THE ADVANTAGES OF MICROWAVE
COMMUNICATION:
➨THE MICROWAVE SPECTRUM HAS LARGER BANDWIDTH AND
HENCE LARGE AMOUNT OF INFORMATION CAN BE TRANSMITTED
USING IT.
➨DAY BY DAY RADIO FREQUENCY SPECTRUM IS GETTING
CROWDED. MICROWAVE TECHNOLOGY HELPS TO MANAGE
CROWDED SPECTRUM WITH THE USE OF HIGH SELECTIVE
RECEIVERS, MODULATION (SSB, PSK, QAM ETC.) AND SPREAD
SPECTRUM TECHNIQUES, DATA COMPRESSION ETC.
➨MICROWAVE SPECTRUM IS DIVIDED INTO DIFFERENT CHANNELS
AS PER APPLICATION. THE CENTER FREQUENCIES FOR THESE
11. Disadvantages of Microwave
Communication
AS WE KNOW MICROWAVE IS USED FOR MICROWAVE
COMMUNICATION. FOLLOWING ARE THE DISADVANTAGES OF
MICROWAVES:
➨FOR THE FREQUENCIES WHICH ARE BELOW 30MHZ STANDARD
CIRCUIT ANALYSIS CAN BE APPLIED. FOR THE FREQUENCIES IN
THE MICROWAVE RANGE, E-H WAVE ANALYSIS NEED TO BE
APPLIED.
➨AS WE KNOW LUMPED COMPONENTS SUCH AS RESISTORS,
INDUCTORS AND CAPACITORS DO NOT HAVE SAME
CHARACTERISTICS AT MICROWAVE FREQUENCIES AS THEY HAVE
AT LOWER FREQUENCIES. HENCE IT IS DIFFICULT TO IMPLEMENT
THESE COMPONENTS AT MICROWAVE FREQUENCIES.
➨AT MICROWAVE FREQUENCIES, TRANSIT TIME OF CURRENT
