Ricerc@Sapienza

In this paper, the possibility of using a multiple- ring circular array as an antenna array for Ground-Pene- trating Radar systems is investigated. The theory behind the proposed idea is presented. The preliminary numerical re- sults that are obtained suggest that the proposed configura- tion is promising. It allows achieving a wide frequency band and low dynamic range ratio of excitations, thus simplifying the feeding network. Further interesting requirements may be satisfied by exploiting a combination of deterministic and stochastic synthesis techniques to design the array.

In this paper, a multi-objective approach is applied to the design of aperiodic linear arrays of antennas. The adopted procedure is based on a standard Matlab implementation of the Controlled Elitist Non-Dominated Sorting Genetic Algorithm II. Broadside symmetrical arrays of isotropic radiators are considered with both uniform and non-uniform excitations.

An isolation technique, which does not require conventional circulators, is proposed for the realization of a simple and low-cost aperture-coupled circularly polarized antenna for application to full-duplex devices. The approach is based on the use of slotlines loops to provide surface current cancellation in specific regions of the antenna structure, leading to improved axial ratio and isolation between the ports in excess of 50 dB.