Tolerance Analysis of Near-field Arrays for Biomedical Applications

Focused near-field antenna arrays (NF-AAs) are exploited in a number of contexts. In the present contribution, the attention is specifically addressed to biomedical applications, such as medical imaging and hyperthermia. These require high performance to guarantee patient safety and accurate diagnostic tests; therefore, spatially correlated and random errors must be considered in the design stage, as they can degrade the generated electromagnetic field or measured data. In principle, spatially correlated errors can be managed and made negligible, but random errors are unpredictable and more challenging to eliminate. Consequently, there is a need to investigate the behaviour of the electric field in the presence of random errors, and to observe the main introduced effects. In this work, a partial characterisation of the stochastic electric field is first performed, by determining the mean, variance, and mean squared magnitude of the electric field. Subsequently, the probability distribution function of the focus depth is determined to have a more general representation.