Retrodirective array tracking prediction using active element characterisation

The authors report on the comparison between the measured and predicted monostatic radiation pattern of a four-element retrodirective array (RDA) operating at 1 GHz. Predictions of array performance were carried our using an isolated element approach then an active element approach. Classical modelling of the RDA performance yielded a worst-case amplitude error with respect to measurement of 3.7 dB at 50° from boresight while an adapted model presented which allows active element pattern incorporation yields an error of only 0.5 dB at 50°. In addition, the individual active pattern characterisation approach allows for the first time a rationale for why measured RDA tracking capability is better than previously established theoretical prediction