Active array radar nonlinearity requirements- spectral analysis of third order intermodulation clutter

A method of developing active array radar system nonlinearity requirements is presented. The interference spectrum due to the mixing of two clutter sources is derived including third-order intermodulation effects. Clutter sources are modeled as independent zero mean Gaussian random processes. The interference power spectrum normalized to thermal noise is plotted parametrically and the resulting curves allow specifying the overall system two-tone third-order intercept point. The required system spurious-free dynamic range can then be computed both at the input to the antenna transmit/receive (T/R) module, and at the input to the analog-to-digital converter.