FMCWssä

FMCW stands for Frequency Modulated Continuous Wave. It is a type of radar system that transmits a continuous wave of radio energy whose frequency is varied in a predictable way over time. This variation is typically a linear sweep, either upwards or downwards in frequency. The system then receives the reflected signal from targets and compares its frequency to the transmitted frequency at that same instant. The difference in frequency, known as the beat frequency, is directly proportional to the distance of the target.

The core principle behind FMCW radar is the Doppler effect combined with the frequency sweep. As the transmitted frequency changes, the reflected signal from a stationary target will have a different frequency than the transmitted signal. This frequency difference is the beat frequency. For a moving target, the Doppler shift further alters the frequency, and by analyzing both the beat frequency and the Doppler shift, both the range and velocity of the target can be determined simultaneously.

FMCW radar systems are often characterized by their simplicity, relatively low cost, and ability to provide range and velocity information. They are widely used in various applications, including automotive radar for adaptive cruise control and collision avoidance, industrial level sensing, altimeters in aircraft, and even in some weather radar systems. The continuous nature of the transmission also means that FMCW radar generally consumes less peak power compared to pulsed radar systems, making them suitable for applications where power efficiency is a concern. The processing of FMCW signals involves mixing the transmitted and received signals to generate the beat frequency, which is then typically analyzed using Fourier transforms.