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Electronics Electronics

What are Microwave Signals?

By Katharine Swan

Updated: May 16, 2024

Most households these days have a microwave, a device that uses microwave signals to cook food rapidly and efficiently. As a result, most people are familiar with the term microwaves. However, many people do not fully understand what these signals are, or how often they are used in modern society.

All electromagnetic waves oscillate in a wave pattern; if you imagine it as a wavy line drawn on a piece of paper, the wavelength is the length of the part that repeats over and over. Short wavelengths create higher frequency waves, and long wavelengths create lower frequency waves.

By definition, a microwave is any type of electromagnetic wave where the wavelength is less than one meter. Microwave signals are similar to radio broadcasting signals, with the primary difference being that radio waves are longer than a meter. This means that they are of a higher frequency than radio signals.

Although microwave signals are technically defined as radiation, they are not to be thought of as the same type of radiation that is dangerous to living creatures, such as the ionizing radiation caused by a nuclear weapon. They simply "radiate" from their source.

Microwave signals have the advantage of being more focused, and more resistant to interference than radio waves. As a result, they have been used more a variety of communication purposes. In the 1940s and 1950s, long distance phone calls were carried from tower to tower using these signals. Today, some cell phone networks and wireless devices such as Bluetooth® use low frequency, or longer-length, microwave signals.

Besides telecommunication, these signals are used in many technologies that we use every day. For instance, they're often used by regular television broadcast stations and wireless Internet connections. Likewise, low frequency microwave signals are present in the cables that provide cable TV and high speed Internet access.

Microwave signals are also being used in other forms of technology. For example, satellites orbiting above Earth utilize microwave communications. Although they are not lethal, they are used in a weapon known as the Active Denial System, which uses microwave-induced heat to control crowds and prevent targets from approaching.

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Discussion Comments

By anon310564 — On Dec 24, 2012

What alien technology are people talking about? These signals are found in nature all over the universe and are just a specific wavelength of electromagnetic radiation. The EM spectrum is we;; known and there's nothing alien about it.

The waves they are emitting are lower energy than visible light so just as you can get cooked by the sun, it's all about dose. If you're concerned about the cell phone in your pocket, get a half-sleeve Faraday cage to absorb the energy going into your pants from having the phone in your pocket. I'd be more concerned about the higher energy UV hitting your skin on a sunny day than the signals coming out of your mobile.

By anon300931 — On Nov 01, 2012

Yes, microwaves are alien technology. I was looking into the origin of microwaves and such and I discovered that the first use of a microwave was apparently on Air Force One in 1947. The UFO crash in Roswell was in 1947. Quite curious if you ask me.

I also learned that microwaves, which we are exposed to constantly through the use of "modern technology", affect the water and fat in our bodies. I found this also to be quite curious. We are full of water and the obesity rate is very high in the U.S. and elsewhere. These microwaves are definitely harmful at the rate we are being exposed to them.

And Nathan had said "Yes, I’ve heard that microwave signals do something to the food, too..." What do you think microwaves are doing to us? And it seems there is no way to escape these waves. We are exposed to them at every angle. I wonder how they will "change" us. And this weapon that wiseGEEK talks about, the Active Denial System, which uses microwave-induced heat to control crowds and prevent targets from approaching. Tell me that doesn't freak you out just a little.

Time to go back to the old ways. It seems to be the only way if we don't want to be mutated. Peace and love to you all!

By ahain — On Jun 03, 2011

Did you know that microwave signals are related to sound waves and the visual light spectrum? I researched this stuff for my digital photography class. As it turns out, sound waves, light waves and microwaves are all exactly the same thing: just different lengths of the same kind of waves.

It's a really interesting concept to think that if sound waves were a different length, we could see sound, and if microwaves were a different length, we would be able to hear them. Now imagine if somebody invented a wave reading device that could make new colors out of sounds, or sounds out of colors, or both out of microwaves! Really cool stuff.

By miriam98 — On Jun 03, 2011

@allenJo - Microwave Internet is offered in our localities although I don’t think it’s for mass use. Here and there I see a microwave antenna on a tower along the highway. I’m not sure if these transmissions are for residential or industrial applications, but we do have a few of them. A friend of mine who works in telecommunications pointed them out to me.

By allenJo — On Jun 03, 2011

@NathanG - Microwaves are all around us, they’re nothing to fear. They’re even used for some Internet transmissions. Microwave signal generators transmit the signals in much the way that cell phone towers operate, stationed at various locations along the way. I understand that it’s being offered as an alternative to DSL, cable modem and satellite, and that it can transmit long distances and support large bandwidths.

It’s not offered where we live and I think it’s a fairly new standard, but I think it would be useful for some people. My point is that if they’re willing to beam microwaves over people it’s probably not going to harm them (keep our fingers crossed).

By NathanG — On Jun 03, 2011

@everetra - Yes, I’ve heard that microwave signals do something to the food, too; they change the molecules in some way. I don’t remember the scientific explanation for that or even if it’s true, but I’ve heard it more than once—that if you even boil water in the microwave it changes it somehow.

Again, I don’t know if it’s urban legend or what, but it’s a fact that chefs look down on microwave cooking. I suppose that has more to do with the flavor of the food than it does with anything happening at the molecular level though.

By everetra — On Jun 03, 2011

I don’t know - I’m still susceptible to the idea that microwave frequency can be harmful to your health. I’ve been told over and over never to stand in front of a microwave while the food is cooking; maybe it’s not true but this article does not reassure me. I always step away; microwaves are convenient but they are a completely alien technology.

The idea of zapping food from the inside out using a form of radiation, however loosely you define that term is still, in my mind, a technology with its own potential hidden perils. It’s like cell phones. Some people argue that they can lead to cancer; others argue otherwise.

In both cases the one common denominator between cell phones and microwaves is the same: they emit waves, and you don’t really know what effect this can have on your body.

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