Contribution to the choice of sub-array antenna architectures.

Summary In order to reduce the material complexity and financial cost of a computational beamforming antenna array, it is often necessary to group the elementary sensors into sub-arrays. In this way, the fundamental characteristics of the initial array are preserved: transmitted and received power, gain, beamwidth. There is potentially a large number of ways to operate these groupings and it is legitimate to look for optimal configurations with respect to one or more given criteria. We propose and analyze in detail a number of optimal criteria. Some of them are related to the detection capability of the antenna, while others characterize the estimation performance. We have, moreover, demonstrated correlations between these different criteria, showing in particular that some of them are antagonistic and that there is therefore no universal law that optimizes all the criteria unanimously. The problem of the choice of the clustering law can be presented to the designer in two distinct forms. Either it will be a question of determining the best topology within a family of predefined laws, or it will be a question of finding the best law without initial arbitrariness. For this second approach, we propose to use the simulated annealing algorithm, which has proven to be well adapted to the cost functions involved. Finally, the numerous simulations carried out have allowed us to acquire a certain expertise, expressed in the form of general rules for the design of sub-array antenna architectures.