Dept. of Electron-ion processing of solids, St.-Petersburg Electrotechnical University, 5 Prof. Popov st., 197376, St. Petersburg, Russia

Abstract – The results of complex study of (Ba,Sr)TiO3 (BST) ceramics with magnesium (BSM) and lanthanoid (BSL) additives, which are used to vary the resonant frequency of a dielectric loaded structure in the wakefield accelerating structures are presented. The structure consists of a thin layer of ferroelectric material backing a layer of linear ceramic with high quality factor. The interdigital electrodes formed on the external surface of double ceramic layer are used to apply DC bias voltage to vary the permittivity of the ferroelectric layer and tune the overall frequency of accelerating structure. Three different techniques of electrode-less measurements of microwave dielectric characteristics of ferroelectric ceramics are presented. Suitable material for this application is BST ferroelectric-oxides compound with a dielectric constant of 300-500. A tuning range of 2-4 % could be achieved for an 11-13 GHz dielectric accelerating structure.