MULTIRESOLUTION ANALYSIS OF ANTENNAS: TRIANGULAR MESH TESTS P.Pirinoli, G.Vecchi, F.Vipiana, L.Matekovits, G.Dassano M.Orefice Dipartimento di Elettronica, Politecnico di Torino, I-10129 Torino, Italy Tel: +390115644090, Fax: +390115644015 e-mail: pirinoli@polito.it Abstract A Multi-Resolution (MR) approach to the EFIE analysis is presented, that keeps the different scales of the problem directly into the basis functions representation. The basis is constructed via the ”dual-isoscalar” technique introduced by the authors, and possesses both spectral and spatial resolution, that can be shown to be crucial in handling the condition problem: the obtained MoM matrix is stable against clipping sparsification, and the use of iterative solvers convenient. The presented technique works for both rectangular and triangular meshes: in this contribution test problems meshed with a triangular grid will be considered. INTRODUCTION The design-oriented numerical simulation of large and complex printed arrays involves struc- tures that are electrically large yet with fine geometrical details requiring much-smaller than wavelength discretizations. When the EFIE-MoM approach is used, the necessity of represent- ing different scale geometries impacts on the size of the resulting Z-matrix that, together with its poor conditioning are the key limitations of this approach. On the other hand, the presence of different electrical lengths in the structure geometry results in very different scales of varia- tion in the solution. Local interactions in sub-wavelength details, or in proximity of edges and discontinuities, generate small-scale details - with high spatial frequency- in the solution while distant interactions - as well as resonant lengths - are responsible for the low-(spatial)frequency, slow spatial variations. A number of techniques have been presented in the past years to overcome the above diffi- culties (see e.g. [1, 2, 4, 5, and ref. therein]). In [3] authors have been introduced a different approach, based on keeping the different scales directly into the formulation and solution process, a typical Multi-Resolution (MR) instance; this leads to a good control of the conditioning of the matrix, a key in the convergence of iterative solvers, as well as the gateway to sparsification of the matrix. In [3] results of the application of the scheme to rectangular meshes have been presented; here test problems meshed with a triangular grid are considered. “DUAL-ISOSCALAR” MULTIRESOLUTION SCHEME The use of “wavelet” functions has generally been limited to the analysis of scalar or 1D problems, due to the intrinsic difficulties of generating and employing “vector” MR (wavelet) functions on 3D or 2.5D structures. The “Dual-IsoScalar” (DIS) approach introduced by the authors in [3] and here only briefly summarized overcomes this limitation. The generation of the MR basis is approached dividing the unknown surface current into its solenoidal (TE) and quasi-irrotational (quasi-TM, qTM) components, that can be mapped to scalar quantities that posses the same degree of regularity in both (local) spatial directions, and