What Does RF Stand For?

Simply, RF stands for Radio Frequency. This generally refers to all of the electromagnetic spectrum that is used for radio systems and wireless communication. However, RF can also mean a variety of different things depending on the context of use. On some occasions when discussing spectrum, RF refers to the frequency range below microwaves, which in turn is below millimeter waves. This can be particularly confusing, as there is no distinct definition of microwaves, as used in industry. It would stand to reason from a physical perspective that microwaves would refer to the electromagnetic spectrum where the wavelength of the signals are in the micrometer range. This, however, is not the case for the term microwaves, as the term’s origin was likely not a physical definition but used to establish that the wavelengths used for early “microwave” systems was much smaller than radio frequency, or radio wave, systems of the time.

This is often why many legacy publications and documentation include the terms RF and microwave when discussing the industry that deals with electromagnetic phenomena from kilohertz to sub-terahertz. An interesting note is that how millimeter-waves is commonly used actually does refer to the physical wavelength of the signals in this spectrum. This comes at odds with some definitions of microwaves, as the definition for millimeter-waves and microwaves overlap. In many cases, the frequency range described by RF also overlaps with microwaves. This is likely why many industry professionals discuss relevant frequencies in terms of waveguide frequency bands, radar frequency bands, or frequency bands used for specific applications, such as 2.4 GHz, 5 GHz, and 6 GHz for Wi-Fi wireless communications and networking.

The term RF is also used to apply a distinction between components, devices, sub-systems, and systems specifically used for electromagnetic communication and sensing from other electronics, electrical, and electromagnetic disciplines. For instance, there are multiple types of bandpass filters, mixers, amplifiers, etc. Without the RF distinction, it would be difficult to discern if these products were designed for audio, ultrasonic, RF, AC electrical systems, or other applications. This is another point of confusion, as the terms microwave and millimeter-wave are often used in the same way to describe electromagnetic communication and sensing products. Hence, there is a field of terms to describe these products and technology resources, which often makes searching for and finding applicable technologies difficult without the correct nomenclature.