Unguided Media

In the last post we have discussed about Transmission media and also about Guided media. Now let’s see about the Unguided Media.

An unguided media transports electromagnetic waves without a physical conductor. It is commonly referred to as wireless media. Do you know if unguided media don’t use physical conductor then how they are transmitting? and what kind of waves they are transmitting?
Let’s see them all in detail.

How they transmit it??

In here the transmission and reception of data is carried out using antennas. These antennas work in two main different ways.

• Directional
  Directional antenna(beam antenna) is an antenna which radiates or receives data or electromagnetic waves in a specific direction only. It increase the performance and reduce interference from unwanted sources.
• Omni-directional
  It is a class of antenna which radiates or receives electromagnetic waves in all directions, and this type of antennas are widely used for radio broadcasting, cell phones and wireless computer networks.

What are the electromagnetic waves used for transmission??

We can divide those waves into three broad groups;

1. Radio Waves
   The electromagnetic waves in a frequency range between 3 kHz to 1 GHz are called as Radio waves. This waves are omni-directional. So that the sending and receiving antennas do not have to be aligned. This kind of waves are widely used for broadcasting.
2. Micro Waves
   These are in frequency range between 1 GHz to 300 GHz. Micro waves are unidirectional, so when an antenna transmits microwaves, they can be narrowly focused(antennas need to be aligned). This is very useful for uni-cast communication. This can be used for long distance communication, and it can carry 1000’s of voice channels at the same time.
3. Infrared Waves(IR)
   These are the waves with frequencies from 300 GHz to 400 THz. Because of it’s high frequency, IR waves cannot pass through walls like radio waves. So it is not possible to use it for communication between different rooms or different houses in a neighborhood. But IR is more private than others.

That’s all for this post. See you all with another interesting topic soon.