Patent ID: 8866667
Filing Date: 2014-10-21
Classification: G01S,H03L

Abstract:
1. A frequency modulated continuous wave (FMCW) radar comprising: a single antenna; a transmit path coupled to the single antenna and configured to provide a FMCW signal thereto, the transmit path including a voltage controlled oscillator controlled by a phase-locked loop, the phase-locked loop including a fractional-n synthesizer integrated circuit (IC) configured to implement a FMCW ramp waveform that ramps from a starting frequency to an ending frequency and upon reaching the ending frequency returns to the starting frequency to ramp again; a receive path coupled to the single antenna and configured to include a reflected version of the FMCW signal as a reflected signal and a portion of the FMCW signal leaking through a circulator as a leakage signal, the receive path including components configured to filter and sample a signal in the receive path; and a delay path coupled between a coupler on the transmit path and a mixer in the receive path, the delay path including a delay element configured to delay a local oscillator reference signal from the transmit path such that the propagation time of the local oscillator reference signal from the coupler to the mixer through the delay path is between the propagation time of the reflected signal and the propagation time of the leakage signal, wherein the mixer is configured to subtract the local oscillator reference signal from the signal in the receive path.