What is a microwave and what is its use?

Radio waves are electromagnetic waves with minimum amount of energy, maximum wavelength and lowest frequency. Radio waves are mostly used in radio and television communication systems. The frequency range of radio waves is 500 kHz to 1000 MHz. Shortwave bands use higher frequencies up to 54 MHz. The television communication system uses the frequency range of 54 MHz to 890 MHz, while the FM radio band uses the frequency range of 88 MHz to 108 MHz.

Radio waves are “omnidirectional” so direct transmission and alignment of antennas are not required. However, the omnidirectional nature of radio waves is also a downside, because when signals are transmitted in the same frequency range, radio waves transmitted from one antenna are prone to interference with other antennas.

Some of the main differences between radio waves and microwaves are as follows:

• Radio wave has low energy and low frequency wave. On the other hand, microwaves are waves with high energy and frequency.
• Radio waves are usually transmitted through the sky. On the other hand, microwaves propagate in the line of sight.
• The nature of radio waves is omnidirectional. In contrast, microwaves are unidirectional in nature.
• The wavelength range of radio waves is more than one centimeter. The wavelength range of microwaves is between 1 cm and 1 mm.
• Radio waves may cover long distances. Microwaves may cover shorter distances.
• Radio waves are widely used in cellular systems, AM, FM. In contrast, microwaves are commonly used in microwave ovens, radar systems, and air navigation.

Microwaves are used in various fields. In industry, microwaves are used to dry and process plywood, process rubber and resin, prepare bread and donuts, and cook potato chips. Microwaves are high-energy waves that can easily heat or melt objects. For this reason, one of the main applications of microwaves is in industrial heating. Microwaves are also used in rotational spectroscopy.

Some of the most important applications of microwaves are mentioned below.

Microwaves are the primary carriers of high-speed data transmission between ground stations as well as between ground stations and satellites and space probes.

Microwaves are used in a number of communication techniques such as satellite communication, cellular communication, point-to-point communication, spacecraft communication, wireless communication, optical communication, and more. The high frequency and ability to propagate at the speed of light enable microwaves to transmit signals over long distances with minimal loss.

A radar system, or “radio detection and navigation,” uses microwaves to determine the location of an obstacle. Microwaves can easily propagate in space and atmosphere. This characteristic of microwaves helps to determine the shape and exact location of the obstacle. The microwaves emitted from the transmitter antenna are directed towards the target. In the collision with the target object, part of the energy is reflected and results about the obstacle are obtained.

Radar beams are composed of short microwave pulses. It is possible to determine the distance of the plane or ship by measuring the time it takes for such a pulse to reach the desired object and return to the radar antenna after reflecting from it. In addition, by using the change in the frequency of the reflected wave pulse caused by the Doppler effect, it is possible to measure the speed of objects (the change in the frequency and length of sound waves caused by the relative speed between the source and the receiver is called the Doppler effect).

Microwave radar is used to guide planes and ships and to detect high-speed drivers. Microwaves can penetrate smoke clouds, but are scattered by water droplets. Therefore, they are used for mapping atmospheric disturbances and in weather forecasting.

The most common consumer use of microwave energy is in microwave ovens. Microwaves have three properties that allow them to be used in cooking: they are reflected by metal, pass through glass, paper, plastic, and similar materials, and are absorbed by food.

Microwaves are absorbed by water and fat in food (for example, water and fat in meat) and generate heat from inside. In most cases, this will greatly reduce the cooking time.