Published: May 23 2025 By: Rungreuang Huanraluek
What are radio frequency waves and electromagnetic waves?
Basic understanding of communication via wired and wireless signals
Basics of Radio Frequency Waves, Electromagnetic Waves, and Frequency Bands – Part 1
Have you ever listened to the news or music on the radio via FM waves, or watched TV through a digital antenna? Did you know that the 4G/5G mobile signals you use for calls and social media, as well as the Wi-Fi internet in hotels or offices, all operate through the same thing — electromagnetic waves? These invisible waves are the core of all wireless communication in the digital age.
This article will guide you through the fundamentals of electromagnetic waves and radio frequency (RF) — what they are, how they work, and why systems like AM/FM radio, mobile phones, Wi-Fi, MATV, and IPTV are all connected to them. If you work in the field of communication systems or simply want to gain a deeper understanding of the wireless world, this is an article you won’t want to miss.
Electromagnetic waves are a form of energy that radiates in all directions. They consist of electric and magnetic fields oscillating perpendicular to each other and moving together through space. These waves can travel without the need for a physical medium, such as air or signal cables. This allows them to propagate through the air—and even through the vacuum of space.
Examples of Electromagnetic Waves in Everyday Life
Frequencies between 3 Hz and 3000 GHz (3 THz) are the most widely used by humans in various systems such as radio, television, telephones, satellites, wireless internet, Wi-Fi, and radar.
Radio frequency (RF) waves have different properties depending on their frequency. For example
- Low-frequency waves can travel long distances and penetrate obstacles well, but they have lower data capacity.
- In contrast, high-frequency waves can carry more data and transmit faster, but they are more sensitive to obstructions.
Radio Frequency Band Classification Table
Radio frequency (RF) bands commonly used in communication systems can be categorized based on their applications. For example, the VHF to UHF bands are the core of digital TV systems, FM radio, and centralized TV systems such as MATV and CATV, which are used in hotels, hospitals, condominiums, apartments, dormitories, and housing projects. On the other hand, the SHF to EHF bands are used in Wi-Fi systems (2.4GHz and 5GHz), radar, and 5G networks, which require high-speed data transmission and higher frequencies in limited areas.
The ELF to VLF bands are specialized frequency ranges, commonly used in military operations, such as communication with submarines or special equipment that needs to penetrate through soil or seawater.
For professionals working with systems such as MATV, IPTV, Wi-Fi, 5G, or network infrastructure, understanding RF frequency bands is essential for selecting the right equipment—such as antennas, signal cables, boosters, and transmitters/receivers—accurately and appropriately. For instance, integrated TV systems should be designed to cover the VHF/UHF bands, while wireless network systems should prioritize devices that support the SHF/EHF bands to effectively meet the specific requirements of each application area.
