What are Radio Waves?

Radio waves are a type of electromagnetic radiation. Radio waves are commonly used for communication. Sounds and images from television, radio, and cell phones all come from radio waves. All of these devices receive radio waves which are converted to mechanical vibrations in the speakers. These mechanical vibrations create sound waves that we can hear.

Electromagnetic radiation is transmitted in waves at different wavelengths and frequencies. The range of wavelengths is referred to as the electromagnetic (EM) spectrum. Regarding the EM spectrum, radio waves have the longest wavelengths. Their wavelengths range from 0.04 inches to more than 62 miles. Additionally, they have the lowest frequencies on the EM spectrum.

According to the National Telecommunications and Information Administration, radio waves are divided into nine different bands. The nine bands are as follows: Extremely Low Frequency (ELF), Very Low Frequency (VLF), Low Frequency (LF), Medium Frequency (MF), High Frequency (HF), Very High Frequency (VHF), Ultra High Frequency (UHF), Super High Frequency (SHF), and Extremely High Frequency (EHF).

EMI / RFI shielding

There are times when protection against frequencies will be needed to avoid interference. This protection is known as Electromagnetic Interference (EMI) Shielding and Radio Frequency Interference (RFI) Shielding.  EMI Shielding and RFI Shielding are of particular importance when it comes to telecommunications because radio transmissions can hinder the reception of a signal by a recipient if the signals are near the same frequency.

Related Reading

• The FCC and RFI
• EMI Testing
• Flexible Circuits and EMI
• Custom EMI/RFI Shielding
  Even though EMI and RFI must be shielded, that doesn't mean that product design must suffer.