FMCW linearizer bandwidth requirements

The frequency-modulated continuous-wave (FMCW) linearity achievable as a function of the bandwidth of the linearizing frequency sweep modulator or linearizer is analyzed. This analysis pertains to millimeter-wave (MMW) radar seekers for short range air-to-ground missiles that employ the FMCW waveform because of weight, volume, and prime power advantages. Fine range resolution, which depends on good frequency sweep linearity, improves the target-to-clutter power ratio by reducing the clutter area. This analysis shows that an extremely wide bandwidth linearizer is required for high range resolution with the sawtooth FMCW waveform. Time gating at the ends of the frequency sweep significantly reduces the nonlinearity. Triangle FMCW requires less linearizer bandwidth than the sawtooth modulation for a given linearity.<<ETX>>