In short, radio frequency (RF) works by measuring the radio spectrum frequencies to provide useful data. But let’s dig a little deeper.
The radio spectrum is from the upper limit of audio frequencies to the lower limit of infrared. It is generally considered to be from 3Hz (ELF) to 300GHz (EHF), with frequencies above 1 GHz considered microwave. The measurement and transmission of radio waves are used for communications, medical treatments and various testing instruments, among many other applications. Radio frequencies are useful because, at lower frequencies, they can travel far with little to no harm to humans. As radio frequency approaches microwaves, the shorter wavelengths can offer some advantages due to the increased frequency, but can also cause harm to humans if exposed for prolonged periods.
Leveraging longer wavelengths to send and receive transmissions forms the basis of RF measurement for Finna Sensors.
When measuring a material for moisture content, we apply an electric charge to measure the oscillation rate of alternating electrical currents or voltage in a circuit. It does this by creating a capacitor that uses two isolated plates that are separated by a dielectric (non-conductor). A small RF signal is applied between the plates to measure the dielectric response. In a simple setup, capacitance is reflected as AK/d, where A is the area of the plates, K is the dielectric constant of the non-conductive material between the plates and D is the distance between the plates. Capacitance can be thought of as a measure of the non-conductive material between two plates. The lower the number, the lower the amount of conductive material between the plates. Contrast that with two plates measuring water, a very conductive material, then capacitance is high. The magnitude of the capacitance can be used to determine the amount or percentage of moisture in a certain sample of material.
Early patents from us and others in the 60s looked at capacitance and radio frequency measurement to determine humidity/moisture content in a sample. These techniques rapidly improved to today’s use in handhelds, online sensors and lab instruments.
However, we are unique in that our technology measures from 2KHz to 2MHz, allowing us to offer a wide range of frequencies to address specific application needs.
From continuous measurement to lab to final quality control checks, we can help you create the right integrated solution to optimize your efficiency and increase your profits.