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a b s t r a c tIn the frame of the EFDA task HCD-08-03-01, a 5 GHz Lower Hybrid system which should be able to deliver 20 MW CW on ITER and sustain the expected high heat fluxes has been reviewed. The design and overall dimensions of the key RF elements of the launcher and its subsystem has been updated from the 2001 design in collaboration with ITER organization. Modeling of the LH wave propagation and absorption into the plasma shows that the optimal parallel index must be chosen between 1.9 and 2.0 for the ITER steady-state scenario. The present study has been made with n || = 2.0 but can be adapted for n || = 1.9. Individual components have been studied separately giving confidence on the global RF design of the whole antenna.

A hybrid electromagnetic-statistic approach for the detection and localization of a perfectly-conducting circular cylinder, buried in a lossless half-space, is presented. We use the results of a cylindrical wave approach forward solver as input data for our detection procedure. We use a sub-array processing structure and apply several algorithms for the direction of arrival estimation. By triangulating the found directions of arrival, a set of crossings, condensed around the object locations, is obtained. To process the crossing pattern, we developed a statistical model for the crossings distribution and employed hypothesis testing procedures to identify a collection of small windows containing the target. By defining a suitable threshold from a desired false alarm rate and dividing the region in small windows it is possible to ascribe each window to the ground or to the object. Numerical results are presented for a cylinder in a vacuum and in a dielectric half-space, both in a central and in a peripheral position with respect to the array centre. Different values of the cylinder radius and of the distance from the array are considered

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A localization technique for buried metallic and dielectric objects is proposed and tested. An array of isotropic antennas investigates a scenario with cylindrical targets buried in a dielectric soil. The targets are in the near field of the array, and a Sub-Array Processing (SAP) approach is adopted: the array is partitioned into subarrays, and Direction of Arrival (DoA) algorithms are used to process the electromagnetic field received by each subarray and estimate the dominant arrival direction of the signal. By triangulating all the estimated DoAs, a crossing pattern is obtained. It is filtered by a Poisson-based procedure and subsequently elaborated by the -means clustering method in order to distinguish between targets and background, estimate the number of targets, and find their position. Several simulations have been performed to compare different DoA algorithms and to test the localization method in the presence of two buried cylinders. Different values of the permittivity of the involved dielectric materials have been considered; the target positions and size have also been varied. The proposed procedure can be useful for ground-penetrating radar applications, near-surface probing, and for the detection and localization of defects in a hosting medium.