A voltage-controlled tunable thin-film distributed RC notch filter

Notch filters are widely used in communication and instrumentation systems not only for eliminating undesired frequencies and for measuring transient harmonic distortions, but also as central components of selective filters and oscillators in feedback arrangements. This paper describes the characteristics of a thin-film distributed RC (DRC) notch filter made from Au/TaN/Y-doped BaTiO/sub 3/ (Y-BT)/Pt. The dielectric (Y-BT) and resistive (TaN) films were grown by pulsed laser deposition (PLD). A notch frequency of 2.8 MHz and notch depth of -76.7 dB were measured from zero with a notch resistance (R/sub N/) of 34 /spl Omega/. The experimental optimum notch parameters of /spl alpha/=R/R/sub N/=19.7 and x/sub n/=/spl omega///spl omega//sub 0/=33.0 were obtained. Tunability of the notch frequency was observed with an applied DC bias voltage.