*Laboratoire de Physique des Plasmas- Laboratorium voor Plasmafysica, Association "Euratom-

The ICANT code solves the antenna radiation problem using a finite boundary element technique combined with a spectral solution of the interior problem [1-3]. The code has been tested by computing the current distribution on the central conductor and screen of simplified ICRH antennas in different cases: in vacuum [1] and in the presence of plasma [2], without or with magnetic shielding effects [3-5]. The unrealistic features (spurious modes such as screen modes), found when using the idealised infinite screen model, are removed by the consideration of a more realistic array of finite blade elements to describe the screen. The Q1 antenna used in the Tore Supra tokamak has shown hot spots [6] and to better understand their origin, it is necessary to know the electric field structure in front of it. To achieve this goal, specific current elements have been constructed which either describe the tilted screen blades or allow to model a tuned antenna [7]. In the following, the computation parameters correspond to the Q1 antenna of the Tore Supra tokamak (Ro = 2.3 m, a = 0.74 m, Bt = 3 T, ne = 1019 m-3, ly =0.7 m, lz = 0.23 m and n = 48 MHz). 2. Magnetic shielding effects on realistic antennas. Due to the current self-consistency, magnetic shielding effects occur and modify th