Contents I. Introduction
Recently, some applications such as antennas and filters have shown the interest of the LTCC at very high frequencies [1]. Rectangular resonators with metalized vias in LTCC technology are used to design SIW filters, but their size, around one millimeter, make them more sensitive to dimensional tolerances of the LTCC manufacturing process. The shortcomings of the realisation can be broken down into several categories: the resolution and tolerances of the circuit metallization, thickness variations and misalignment between the different layers, the tolerance on the shrinkage [2]. In addition, the material characteristics are not known at these frequencies and are subject to extrapolation from data at lower frequencies. The latest comes from a study carried out up to 65 GHz by the Technical Research Centre of VTT [2]. This leads to answers often far from experimental responses obtained by electromagnetic simulations. Some non-destructive methods have been developed with small volume of needed material at low frequencies [3] but are not tried at high frequencies. We want to develop volume resonators, one hand to limit the sensitivity to geometrical defects and also to know the complex permittivity of the material used in this technology with a good accuracy for the imaginary part.
