Do You Know The RF Fundamentals?

For all its simplicity to the end user, Wi-Fi is really an incredibly complex technology. In this series, we “get back to the basics” of the technology.

Wi-Fi is an essential part of many of our lives. We have passed the point at which wireless was simply “nice-to-have”, and now expect it to be a mandatory component of our environment— in our homes, places of work, and even while we are out shopping or on vacation.

Despite how much we rely on wireless technology, a majority of its users have no idea how Wi-Fi actually works! Over the next few weeks, I will be going “Back to the Basics” of wireless to explain the underlying technology behind Wi-Fi.

This week I will be discussing Radio Frequency Fundamentals.

Very basically, Wi-Fi is made up of stations that transmit and receive data. Wireless transmissions are made up of radio frequency signals, or RF signals, which travel using a variety of movement behaviors (also called propagation behaviors).

RF communication starts when radio waves are generated from an RF transmitter and picked up, or “heard” by a receiver at another location. In order to understand how these signals actually work, we must start with the basics of waves as they relate to the principles of data transmissions.

An RF signal or wave radiates away from an antenna (often in a wireless access point) in a continuous pattern that is governed by properties such as wavelength, frequency, amplitude, and phase. However, the signal’s movement and behavior are also affected by other components such as absorption, reflection, scattering, refraction, diffraction, free space path loss, attenuation, and gain.

Why are all these terms important? These behaviors determine whether you receive enough of an RF signal to actually use the wireless network! Basic explanations of the RF signal behaviors are below-

  • Absorption: most materials will absorb some amount of RF signal as it is traveling between the antenna and the user device. Drywall absorbs a relatively small amount of signal while brick or concrete will absorb a significant amount of signal.
  • Reflection, scattering, refraction, & diffraction: these are all RF propagation behaviors that cause an RF signal to travel in a different direction than it was originally intended.
  • Free space path loss: RF signals spread out naturally as they move away from an antenna, and as a result the strength of the signal attenuates (decreases).
  • Gain: the amplification of an RF signal.

The combination of the behaviors above determine where and how the signal travels through a specific environment. The radio frequency signals have to deal with obstacles and sources of interference before reaching you and your device.

Overall, there are many RF behaviors that affect the signal as it leaves the transmitter (in our case, the antenna on a wireless access point) and travels toward the receiver (whatever device you are trying to connect and use over the Wi-Fi). Hopefully this blog gives you a better idea of what is happening on the back end as you use a Wi-Fi network in your daily lives.

Next week, I will discuss RF Components, or what equipment is needed to successfully transmit and receive an RF signal.

All Posts In The Back To Basics Series:

How to Set Up Online Donations Using The Cloud And School Wi-Fi
Let Technology Help Fund Your School By Simplifying Recurring Online Donations

1) Do you know the RF fundamentals?

2) How are RF signals transmitted? Let’s talk equipment

3) A history of wireless standards

4) Do you know your 802.11 industry organizations?

5) Getting Familiar with Wi-Fi Channels?

6) 2.4 GHz Channel Planning

7) What Are 802.11 Topologies?

8) Radio Frequency And Antenna Concepts


Alexandra Gates is a Senior Product Marketing Manager at Aerohive Networks, where she helps define market strategy and vision for the cloud and WLAN products. She is a CWNA with a comprehensive background in wireless technology, including capacity and management planning, RF design, network implementation, and general industry knowledge.

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