Fmcw radar explanation

Frequency Modulated Continuous Wave (FMCW) radar is a form of radar where the frequency of the transmitted signal is continuously varied at a known rate over a defined time period. The reflected frequency signal is received by the radar and compared.

1. How does a FMCW radar work?
2. What's the difference between FMCW and CW radars?
3. What is beat frequency and how it is used in FMCW radar?
4. What is the range of FMCW radar?

How does a FMCW radar work?

How Does FMCW Radar System Work? In an FMCW system, the transmitter antenna emits frequency modulated continuous radio waves, and the reflected signal from the target is received by the receiving antenna. The output of the receiving antenna is given to the mixer stage of the receiver via a pre-amplifier.

What's the difference between FMCW and CW radars?

The CW radar can measure the Doppler frequency of the target, but it cannot measure the target range. The frequency-modulated CW radar (FM–CW) can measure both the range and Doppler frequency of the target.

What is beat frequency and how it is used in FMCW radar?

This frequency difference is called “beat frequency”. An occurring Doppler frequency would now move the frequency of the entire echo signal either up (moving towards the radar) or down (moving away from the radar). In this form of modulation, the receiver has no way to separate the two frequencies.

What is the range of FMCW radar?

Frequency Modulation is used in FMCW radar. FMCW radars use mm wave electromagnetic spectrum which has very short wavelengths upto 4 mm [9], [10]. The frequency used is in range of 76–81 GHz. Higher frequencies are used so that even smaller objects can be detected effectively.