Sidelobe Suppression in a Range-Channel Pulse-Compression Radar

A model range-channel pulse-compression system is postulated and the problem of suppressing sidelobes in the compressed pulse is discussed. It is concluded that amplitude-weighting in the time domain (at IF) is a convenient method of suppressing sidelobes. An integration loss factor is defined which characterizes the decrease in signal-to-noise ratio (SNR) resulting from the inclusion of weighting. For a radar system which is peak-power-limited, it is shown that the integration loss is less if the amplitude-weighting is accomplished entirely at the receiver while ``mismatching´´ the system, rather than weighting at both transmitter and receiver while preserving a ``matched´´ system. Some common amplitude-weighting functions are compared in terms of integration loss, main-lobe broadening, and sidelobe structure. The Hamming weighting is shown to be a good compromise among the above factors and, in addition, it is relatively easy to implement. The effect of a time-mismatch between the Hamming amplitude-weighting function and an echo pulse is considered for the special case of linear-frequency modulation.