An Experimental Study of Thin Film Distributed Parameter R-C-KR Structures For Their Null Filter Characteristics

Abstract

The voltage transfer function of a thin-film distributed parameter (DP) structure consisting of two resistive films separated from one another by a dielectric film ( referred to as R-C-KR strucure) has been numerically analysed using a digital computer with the objective of locating the null frequency. A few specimens of the thin film R-C-KR structures have been fabricated (employing vacuum deposit ion technique) for experimental study of the null filter characteristics of these structures used in various network configurations. The effects of the resistive load of various magnitudes on the null behaviour of these thin-film structures are graphically displayed by incorporating the experimental results. It is found that the frequency of minimum output voltage remains unaltered for all values of resistive loads. A second fre-quency of minimum output voltage is experimentally found to follow the first frequency of minimum output voltage for one of the configurations of the uniform R-C-KID structure. The frequency of minimum output voltage is observed, perhaps for the first time, to increase and decrease to certain extent when an external capacitive or a resistive element is connected in series with the common ground terminal of the various configurations of this R-C-KR structure. The method of controlling the null frequency by means of external resistive and capacitive elements, as pointed out in this thesis, may be worthwhile to extend to other possible null filter configurations of the multilayer thin-film structures. The highlight of the present experimental study is the initiation of a study of null frequency variation range of integrated thin film structures by means of external resistive and capacitive elements. This problem may be taken up as a novel area for the further investigati