Transmission Media plays a pivotal role in telecommunications providing the way for data to travel between devices, whether it will be through cables, optical fibers, or wireless signals, the choice of transmission medium impacts the speed, reliability, and range of data communication.

Hence, understanding the various types of transmission media and their characteristics is essential for designing efficient and resilient communication networks. In this article, we are going to discuss about unguided media in detail along with different types of unguided media and their advantages and disadvantages.

What is UnGuided Media?

Unguided media is a type of Transmission Media. A transmission medium is a physical path between the transmitter and the receiver. Unguided media transport electromagnetic waves without using a physical conductor. It is also known as unbounded or wireless media, and does not rely on physical pathways to transmit signals. Instead, they use wireless communication methods to propagate signals through the air or free space.

Types of Unguided Media

Unguided Media

1. Radio Waves

Radio waves are electromagnetic signals used for various wireless communication technologies, such as Wi-Fi, Bluetooth and radio broadcasting. Electromagnetic waves ranging in frequencies between 3 kHz and 1 GHz are normally called radio waves. Radio waves are omnidirectional. When an antenna transmits radio waves, they are propagated in all directions. This means that the sending and receiving antennas do not have to be aligned. A sending antenna sends waves that can be received by any receiving antenna. The omnidirectional property has a disadvantage, too. The radio waves transmitted by one antenna are susceptible to interference by another antenna that may send signals using the same frequency or band.

Let’s talk about the Omni directional Antenna now.

Omni Directional Antenna

Radio waves use omnidirectional antennas that send out signals in all directions. Based on the wavelength, strength, and the purpose of transmission, we can have several types of antennas. Figure shows an omnidirectional antenna.

Applications of Radio Waves

• The Omni directional characteristics of radio waves make them useful for multicasting, in which there is one sender but many receivers.
• FM radio, television, maritime radio, cordless phones, and paging are examples of multicasting.

Advantages of Radio Waves

• It is used in WAN (Wide Area Network).
• Used in mobile Cellular phones.
• Radio wave spread in large area so they can penetrate the wall.
• It’s provide a higher transmission rate.

2. Microwaves

Electromagnetic waves having frequencies between 1 and 300 GHz are called microwaves. Microwaves are unidirectional. The sending and receiving antennas need to be aligned. The unidirectional property has an obvious advantage. A pair of antennas can be aligned without interfering with another pair of aligned antennas.

Let’s talk about the Unidirectional Antenna now.

Unidirectional Antenna

Microwaves need unidirectional antennas that send out signals in one direction. Two types of antennas are used for microwave communications: the parabolic dish and the horn.

Types of Microwaves

There are two types of microwaves:

1. Terrestrial Microwave

Terrestrial Microwave are microwaves that transmits the beam of a radio signal from one ground based antenna to another ground based antenna.

Characteristics of Terrestrial Microwave

• Frequency range: The frequency range of terrestrial microwave is from 4 GHz to 23 GHz.
• Bandwidth: Terrestrial Microwave supports the bandwidth range from 1 to 10 Mbps.
• Short distance:  Terrestrial Microwave inexpensive for short distance.
• Long distance:  Terrestrial Microwave expensive because it requires a higher tower length for a longer distance.
• Attenuation: Attenuation refer loss of signal. It is because of environmental conditions and antenna size.

Advantages Of Terrestrial Microwave

• Terrestrial microwave is cheaper than using cables for communication.
• Terrestrial microwave does not require land for installation so it is free from taking any land space.
• Terrestrial microwave transmission provides easy communication in trains because installation of cables in trains is not a easy task.
• Communication over oceans is achieved by using microwave.

Disadvantages of Terrestrial Microwave

• Line of Sight Required: The signals need a clear path between antennas. Obstructions like buildings, trees, or mountains can block the signal.
• Weather Interference: Bad weather, especially rain, can disrupt the signal, leading to poor performance.
• Distance Limitations: Range for communication is limited. For longer distances, multiple stations are needed, which increases cost and complexity.
• High Initial Cost: Setting up the infrastructure, including towers and antennas, can be expensive.
• Maintenance: Regular maintenance is necessary to keep the system running smoothly, which can be costly and time-consuming.
• Limited Bandwidth: Compared to some other communication methods, the bandwidth available for terrestrial microwave can be limited, restricting data transfer rates.

2. Satellite Microwave Communication

A satellite is a object that revolve around the earth. A satellite microwave is a type of communication technology that uses microwave radio waves to transmit data between a ground-based station and an orbiting satellite.

How Does Satellite work?

A satellite get signal from ground based station, enhance that signal and transfer bak to another ground based station that is situated at different location on the earth. They orbit high above the planet, allowing them to cover large areas. This process enables long-distance communication, GPS navigation, and weather monitoring.

Advantages of Satellite Microwave Communication

• Wide Coverage: Satellites can cover large areas of the Earth, reaching remote and rural locations where other communication methods might not be available.
• Long Distance Communication: They allow for communication over very long distances, including international and intercontinental connections, without the need for physical infrastructure on the ground.
• Reliable: Satellites are less affected by geographical obstacles like mountains or buildings, providing a more consistent and reliable signal.
• Broadcast Capabilities: Satellites can efficiently broadcast information to a large number of receivers simultaneously, making them ideal for television and radio transmissions.
• Flexibility: They can be used for various applications, including internet, phone services, TV broadcasting, and emergency communication.

Disadvantages Of Satellite Microwave Communication

• High Cost: Launching and maintaining satellites is very expensive.
• Signal Delay: Signals travel a long distance to and from satellites, which can affect real-time communications like phone calls and video conferencing.
• Weather Sensitivity: Bad weather, such as heavy rain or storms, can interfere with satellite signals, leading to disruptions.

3. Infrared

Infrared waves, with frequencies from 300 GHz to 400 THz (wavelengths from 1 mm to 770 nm), can be used for short-range communication. Infrared waves, having high frequencies, cannot penetrate walls. This advantageous characteristic prevents interference between one system and another; a short range communication system in one room cannot be affected by another system in the next room. When we use our infrared remote control, we do not interfere with the use of the remote by our neighbours. Infrared signals useless for long-range communication. In addition, we cannot use infrared waves outside a building because the sun’s rays contain infrared waves that can interfere with the communication. It is used in TV remotes, wireless mouse, keyboard, printer, etc.

Characteristics of Infrared Signals

• Infrared signal supports high bandwidth, so the data rate will be very high.
• It can not penetrate the wall. So communication in one room can not be interrupted by the nearby rooms.
• Its provides better security and minimum interference.
• Infrared communication doesn’t work well outside because sunlight interferes with the infrared signals.

Application of Infrared Signals

Below mentioned are the applications of Infrared Signals

• Infrared signals can be used for short-range communication in a closed area using line-of-sight propagation.
• Infrared technology is widely used in security systems, including motion detectors and infrared cameras.
• Infrared sensors are employed in various automotive applications, such as night vision systems and collision avoidance systems.
• Infrared technology is found in many consumer electronic devices, including remote controls for televisions, air conditioners, and other appliances.

Advantages of Unguided Media

• Flexibility: Devices can connect from anywhere within the signal range, providing mobility and convenience.
• Allowing devices to communicate without the need for physical connections.
• Easy to install.
• Scalability: Adding new devices or expanding the network is straightforward and doesn’t require extensive reconfiguration.

Disadvantages of Unguided Media

• Interference: Signals can be disrupted by other electronic devices and weather conditions.
• Security: It is easier for unauthorized people to access and intercept wireless signals.
• Range Limitations: Wireless signals have a limited range.
• Signal Quality: Obstacles like buildings and walls can decrease signal quality.
• Bandwidth: Generally, unguided media can offer lower bandwidth compared to guided media.

Conclusion

In conclusion, unguided media, such as radio waves and infrared signals, offer valuable communication solutions. Radio waves enable omni-directional broadcasting and multicasting, while infrared signals used in short-range, line-of-sight applications. Their applications range from wireless communication technologies to security systems, automotive safety, and consumer electronics, making them integral to modern technology and convenience.

Frequently Asked Questions on UnGuided Media – FAQs

What challenges does interference pose to radio waves in wireless communication?

Interference can disrupt radio waves in wireless communication when multiple devices transmit on the same frequency or band, leading to signal distortion.

What role do unguided media play in enhancing automotive safety?

Unguided media, such as infrared and radio waves, enhance automotive safety through applications like night vision systems and collision avoidance, improving driver awareness and reducing accidents.

What are the example of unguided media?

There are several examples of unguided media like Wi-Fi, Bluetooth, satellite communication, cellular networks, infrared communication, etc.

What are the three major classes of unguided media?

Three major classes of UnGuided media are:

• Microwave Transmission
• Radio Transmission
• Infrared Transmission