Interference mitigation via phase only transmit nulling: Preliminary experimental results

The increasingly crowded RF spectrum necessitates development of techniques that foster coexistence between multiple RF users. Radar systems can typically mitigate received interference using sidelobe cancellation and adaptive beamforming. In the future, radar systems could possibly use similar techniques to produce nulls in the transmit beampattern further reducing RF fratricide. However, transmit nulling is difficult due to the constant modulus constraint associated with the waveforms transmitted by high power radar systems. Several algorithms have been developed that attempt to determine phase only (PO) weights capable of inducing a transmit null. In this talk, the re-iterative uniform weight optimization (RUWO) algorithm is used as a means to produce PO weights from a measured interference covariance matrix.