Propagation Delay → Range

Propagation delay is the time it takes for a transmitted radar signal to travel through space.

By measuring this delay, the distance to the target can be determined.

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Td, propagation delay R, target range c, speed of light

Propagation Delay Effect in FMCW

In an FMCW radar system, propagation delay causes a frequency difference(beat frequency) between TX and RX signals.

Therefore, the target distance can be determined from this beat frequency using the corresponding formula.

The method for measuring the beat frequency is described in the “Mixer” and “How to Measure” sections.

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f_b, beat frequency = f1 – f2 B_RF, Chirp Bandwidth T_c, Chirp Period/Cycle c, speed of light