Dielectric imaging and its frequency dependence of dielectric device using non-contact state microwave probe and FT image refinement

Abstract

Recently, dielectric devices, such as multi-layered ceramics capacitors (MLCCs) have been miniaturized and used at high frequency. The high frequency dielectric measurement technique for local-region is useful for the designing and preparation of these dielectric devices. The dielectric imaging for dielectric device in microscopic area was carried out by non-contact microwave probe. The dielectric device was selected for MLCC, and MLCC was cut to perpendicular for inner dielectric and electrode layers. The reflection intensity images, indicating dielectric images of cross-section of MLCC were measured with scanning non-contact microwave probe for x-y axes, and the dielectric permittivity distribution in microscopic area at GHz order were measured at room temperature. In order to prevent the noise from measurement system, the noise reduction process for obtained raw data was carried out using the two dimensional Fourier transformation technique and filter functi! on. The noise reductions of raw data were processed with developing the software using fast Fourier transform algorism. The clear images of MLCCÇ⨍Ùs inner dielectric and electrode layers were appeared clearly using above technique. The spatial resolution was experimentally estimated to be about 10um from mapping of cross section view of dielectric and inner electrode layers in multi layer ceramics capacitor. The frequency dependence of dielectric permittivity of MLCC was measured with combining an impedance analyzer for lower frequency from 1MHz to 11GHz.