[Physics Class Notes] on Electromagnetic Spectrum Microwave Pdf for Exam

In an electromagnetic spectrum, we observe various electromagnetic waves having their frequency and wavelengths, one of them is the microwave. So, what does microwave mean and what type of wave is a microwave?

Microwaves are produced by special vacuum tubes, namely klystrons, magnetrons, and Gunn diodes and they have many real-life applications.

Reading further, we will learn about what are microwaves used for and what are microwaves made of.

Composition of Microwaves

Microwaves are electromagnetic radiations as UV rays, radio waves, and so on.

These waves have wavelengths ranging from one meter to one millimetre and the frequency ranging between 1 GHz and 1000 GHz.

Applications of Microwaves

Microwaves have many real-life applications, such as microwave ovens, radar systems, detecting the speed of objects like the speed of a tennis ball, automobile, and so on. Now, let’s discuss what are microwaves used for.

1. Space communication, i.e., from earth to space, and vice-versa.

2. Intercontinental telephones and television.

3. In railways, microwaves are used for telemetry communication.

1. Microwaves are used in food processing industries.

2. Other industries where microwaves are used are Chemical industries, plastic industries, rubber industries, forest product-based industries, and so on.

3. Microwave ovens for heating the food items work at 2.45 GHz, 600 W.

4. Microwaves are used in man public works, breaking rocks, drying or breaking the concrete, and curing of cement, etc.

5. It is also used for drying grains, pharmaceuticals, textiles, leather.

1. Microwaves are employed for various diagnostic and therapeutic purposes.

2. They are used in electromagnetic heating for treating cancer patients (Hyperthermia for treating cancer).

3. Used for monitoring heartbeat and if someone is suffering from lung water problem, microwaves can detect the quantity of water in the lungs.

4. Microwaves are also used in diathermy for localized superficial heating.

1. Microwaves are used for tracking missiles, detecting aircraft and other flying objects.

2. Microwaves are also used for calculating the distance of objects and the speed of their flight.

• A practical application of microwaves is the microwave oven. The cooking surface of the oven is composed of ceramic glass. Inside the oven, there are metallic magnetron tubes, the waveguide, and the stirring fan.

The electromechanical components and controls comprise timer motors, switches, and relays, etc.

The materials used for microwave cooking are:

• Paper cups

• Cartons

• Cling films

• Thermoplastics, etc.

Miscellaneous Microwave Applications

There are other places where we find the microwave uses. These are:

• In Air Traffic control (ATC) to detect the movement of the airplane and manage the air traffic.

• Police sped detectors.

• To observe the movement of trains on rails while sitting in the microwave operated control room.

• In defence, microwaves are used in radar systems for aircraft navigation.

• A radar using microwaves can aid in detecting the speed of tennis balls, cricket balls, and automobiles in motion. 

• Observing and analyzing weather patterns.

• Spread spectrum systems. 

• In garage door openers.

• Burglar alarms.

• In creating microwave devices like a microwave oven.

What is a Combination Microwave?

Combination microwaves or combi microwaves are kitchen appliances that are made by a combination of microwave energy, a grill, a fanned hot air (convection heating)  for cooking the food.

Employing these two methods together creates a form of heat that can sauté, grill, bake, crisp, bring even roasting, and brown our food. It is the best method to obtain the speed of a microwave with the high-quality finish of regular oven cooking.

Application of Microwave Engineering

The microwave frequency ranges between 1 GHz and 300 GHz. These ranges are divided into a number of bands, which are symbolized by a letter.

Various organizations assign these bands a letter; however, the most common being employed is the IEEE Radar Bands followed by NATO Radio Bands and ITU Band.

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The frequency range is divided into portions and symbolized by an English alphabet, where each has its specific real-application of microwave engineering; let’s discuss these one-by-one:

• 1-2 GHz – L-Band – GSM, Marine satellite.

• 2-4 GHz – S-Band – Weather and surface ship radar, microwave oven, Bluetooth, Zeebee, Wi-Fi.

• 4-8 GHz – C-Band – These frequency range microwaves are used for satellite communication, Radar applications.

• 8-`12 GHz – X-Band – These frequency rang
  e microwaves are employed for satellite communications and educational purposes, microwave tubes for performing experiments in the lab.

• 12-18 GHz – Ku-Band – These microwaves are used in satellite TV and VSAT.

• 18-27 GHz – K-Band – RADAR, Armature satellite, infrared astronomy (to detect the intensity of stars and ascertain their distance, speed, and many other factors, we use K-band microwaves).

• 27-40 GHz – Ka-Band – Satellite communications, high resolution, and low-range RADAR, military airplane.

• 40-75 GHz – V-Band – High capacity terrestrial millimetre wave communications.

• 75-110 Gz – W-Band – Millimeter-wave RADAR  and research. W-band is employed by ISRO, NASA, DRDO, and other agencies for research purposes.

• 110-300 GHz – mm (Millimetre) – Band – Millimeter-wave RADAR, satellite communications.