A compact pulsed electron beam source based on a channel-spark discharge was studied with the aim to find the optimum operating conditions for an efficient ablation of ferroelectric materials for thin-film deposition. The ablation plasma was studied by time-resolved optical emission spectroscopy. The temporal evolution of the spectral lines of target material and working gas was monitored. In the present discharge configuration a long lasting plasma is characteristic, as proved by the temporal evolution of excited atoms and ions.
Wireless communications systems require new materials with special properties in specific frequency bands. The investigations on ZST type ceramics, (Zr<sub>0.8</sub>Sn<sub>0.2</sub>)TiO<sub>4</sub>, presented in this paper, recommend this materials for applications in microwaves and millimeter waves. The ZST materials were prepared using a standard solid-state reaction technology. The samples morphology, phase-composition and microstructure investigations were performed by using the scanning electron microscopy (SEM), and energy-disperse X-ray spectrometry (EDX). The crystalline phases were identified by X-ray diffractometry (XRD). The electromagnetic properties were investigated on ZST resonators by using a Computer Aided Measurement (CAM) in microwaves, combining a HP 8757C network analyzer and a HP 8350B sweep oscillator. The dielectric characteristics at millimeter waves were analyzed by investigation of the Whispering Gallery Modes on ZST disks. The low level NiO doping provides ZST materials with temperature coefficient τ<sub><i>f</i></sub> in the range (-2 ÷ +4) ppm/°C and decreases the dielectric loss. Materials with high values of the <i>Qf</i> product up to 50,000 and a dielectric constant about 36 at microwave frequencies were obtained. ZST dielectric resonators and substrates for hybrid integrated circuits with dimensions 1” x 1” and thickness in the range 0.6 ÷ 1 mm were manufactured.