What Are RF Signals and How Do They Work?


In December of 2021, the University of Colorado collaborated with the Communications Technology Laboratory to increase the amplitude of microwave-frequency waveforms by a factor of ten. This will, in effect, improve the accuracy and power of RF signals.

If this all seems like Star Trek technobabble to you, you’re not alone. But far from science fiction, this development has far-reaching real-world effects. In order to understand the implications, you need to understand what an RF signal is and how it works.

What Is An RF Signal?

“RF” stands for “Radio Frequency.” The term indicates the oscillation (or repetitive variation) rate of an alternating electric current or an electromagnetic field.

An RF Signal can range from 20 kHz (kilohertz) to about 300 GHz (gigahertz). Those frequencies roughly describe the upper limit of audio frequencies to the lower limit of infrared frequencies.

RF Signals have some important applications, the most common of which is for communications. They are what make transmitters and receivers of all kinds work, such as garage door remotes. They can also be found helping computers, televisions, radios, and mobile phones to communicate.

RF Signals can be used in medical treatments, too. Minimally invasive surgeries use radiofrequency ablation, where the heat that alternating current generates removes dysfunctional tissue from a person’s heart or other body parts.

How Are RF Signals Transmitted?

An RF Signal always needs a transmitter (or RF signal generator). This begins the RF communication by taking the data to be transmitted and encoding this data into a modified signal, which it will then send to an antenna.

Once it has access to the signal, the antenna will direct the RF waves away from itself, toward a second antenna. This antenna is connected to the receiver, which translates the modified signal back into its original data component.

You can send a single data signal to multiple receivers. This is how FM radio is transmitted. The range of the signals, however, may be limited.

The other potential issue is signal degradation. The farther you get from the transmitter, the weaker your signal will become. Enter CRPAs.

What Is CRPA?

Controlled Reception Pattern Antennas, or CRPAs, have been around for decades. They were developed by the United States as an anti-jamming device during the Cold War with the Soviets. They weren’t built for convenience, though, and they were bulky and required multiple cables in order to operate.

Nowadays, however, CRPA systems are more efficient and less awkward to set up and use. This is good news since the applications for such a system are vital to the military.

CRPA antennas replace standard antennas. They each have multiple RF receptors, which receive GPS and jamming signals at slightly different phases.

The CRPA is attached to an Antenna Electronics (AE) module that combines the signals. In this way, the CRPA can maximize the signal and minimize the noise, preventing signal jamming and minimizing distance degradation.

The problem becomes testing the CRPA to make sure it’s operating efficiently. It is difficult to test in a laboratory, due to limited dynamics, and almost impossible to test on an airfield because it is nearly impossible to repeat.

Now, however, there are systems for CRPA simulation that can test a CRPA system effectively. These systems act as RF signal generators and allow users to add interference to the signal. In so doing, they can test how effective their phased-array antenna system is.

A New Era

These CRPA simulation systems are ushering in a new era for RF signals and anti-jamming technology. They can be used in both military and commercial applications, making RF signals cleaner and GPS more reliable.

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