Radio frequency (RF), in simple definition, is a measurement that represents the oscillation rate of electromagnetic radio waves on the electromagnetic radiation spectrum. The frequencies range from 300 GHz on the highest to about 9KHz on the lowest scale. This is roughly between the lower limit of infrared frequencies and the upper limit of audio frequencies.

A radio frequency picks up electric fields through transmitters and antennas and is applicable in various types of communication and wireless broadcasting.

At such frequencies, an oscillating current emits energy that radiates off a conductor and into space in the form of radio waves. Notably, different frequency sources specify various lower and upper bounds for the frequency range.

All you need to know about Ionizing and Non-ionizing radiation

Radiation falls into two basic categories; ionizing radiation and non-ionizing radiation. Ionizing radiation is high frequency higher energy/ short wavelength while non-ionizing radiation is lower frequency lower energy/longer wavelength, which is where the radio frequency falls.

As non-ionizing radiation, RF cannot remove electrons from an atom, due to its low energy. Other notable forms of non-ionizing radiation energy include microwave frequencies, lasers, and ultraviolet.

Alternatively, ionizing radiation comes from radioactive atomic structures as casual particles (neutrons, beta, alpha) or higher electromagnetic waves such as x-rays and gamma rays.

Radiofrequency Unit of measurement

The standard unit of measurement for radiofrequency is hertz (Hz). This is a representation of the cycles made per second once a radio wave is transmitted. One cycle per second makes one hertz.  Radio waves range from thousands to millions to billions of cycles per second, and this is measured in kilohertz, megahertz, and gigahertz, respectively.

A radio wave frequency is inversely proportional to wavelength. Radio frequencies are, however, invisible through the human eyes. As the frequency goes beyond the ranges of the radio frequency spectrum, electromagnetic energy is converted to infrared radiation, microwaves, ultraviolet, visible, X rays, and gamma rays.

Types of frequency bands

The frequencies in the radio frequency electromagnetic network are divided into three basic frequency bands or ranges. These are labeled as high frequency (HF), medium frequency (MF), and low frequency (LF). Apart from the lowest frequency segment, each of the other ranges is a representation of an increase in frequency corresponding to a magnitude order (usually to the power of 10).

Radio waves congestion and interference

The United States government classifies radio frequencies into unlicensed and licensed frequency bands. As such, the issuance of permits for commercial entities is the prerogative of the Federal Communications Commission (FCC).

Licensing

With a license, a commercial entity has rights for the exclusive use of a given frequency range or band in a given location. The entities may include cellular networks, frequency modulation (FM) radio, television broadcasting, military and satellite communications. Unlicensed frequencies, on the other hand, remain free for public use and represent a shared medium.

RF technology  and electromagnetic radiation application

Radio frequency fields are applicable in most types of wireless devices. Cordless cell phones, Wi-Fi and Bluetooth, some of the best portable radio devices and television broadcast, two-way radios, and satellite communication systems all work thanks to the radiofrequency spectrum. In addition, other appliances used every day also use radio waves such as garage door openers, microwave ovens, and many others.

However, other wireless devices may not necessarily fall under the operation of radiofrequency but other portions in the electromagnetic spectrum. For instance, devices like TV remote controls work at infrared frequencies thanks to their shorter electromagnetic wavelengths. Notably, electromagnetic waves travel at the speed of light.

Common uses of RF radiation

Commercially exploited bands. Source: Britannica

Microwave Ovens

A microwave oven heats foods through a very high-level frequency in the radiofrequency radiation portion of the microwave spectrum. As the food absorbs microwaves, a vibration happens within the water molecules, thus producing heat. Microwaves do not use gamma or x-rays, and neither do their energy levels make food radioactive.

Full body security scanners

These are common in airports and other high-security areas. Modern scanners use millimeter-wave imaging in their operation. The then scanner sends out a small amount of a specific type of radio frequency radiation called millimeter-wave imaging towards the target persona. As the radio frequency radiation passes through clothing, it bounces off the skin and any other notable object within and under the clothing. The receivers would then sense the radiation that creates an outline of the person’s image.

Does RF radiation cause cancer?

There have been concerns that human exposure to RF radiation causes DNA damage in the body. Still, lab studies indicate that RF energy waves do not have enough energy to cause direct damage to DNA. While some radio frequency safety studies have noted some increased tumor rates in lab animals exposed to radiofrequency, the study has not been conclusive enough to offer a clear answer.

According to the article on the American Cancer Society’s website, the society is yet to come up with an official position regarding whether or not RF exposure directly causes cancer or other health effects. This could be attributed to the fact that the American Cancer Society usually looks up to other independent expert entities to determine if something is carcinogenic. According to the US Federal Communications Commission (FCC), there is no scientific basis yet that links wireless networks, cordless telephones, mobile phones, or radio frequency exposure to cancer risk or other illnesses.

Final Word

As seen in all other portions of the electromagnetic spectrum, the RF component has the wavelike characteristics of refraction, reflection, absorption, diffusion, and scattering. These characteristics would generally make use of the spectrum by redirecting the energy focus and creating interference. With the right ingenuity, these characteristics can come in handy in enhancing the RF source.

One interesting aspect about RF waves is that all these interactions that can modify waves can remain in operation simultaneously. This means if the waves could be visible by the human eye, we would see a chaotic and complicated swirl of different frequency waves that operate at different power levels.