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A novel Barium-Strontium-Titanate(BST) varactor-tuned spiral bandstop filter (BSF) is presented. The BST varactor operation is based on the nonlinear dielectric tunability of BST thin film sandwiched between two metal layers in a conductor-backed coplanar waveguide(CBCPW) transmission line configuration. The varactor area is formed by the overlap area between the spiral shunt line in the bottom metal layer and the center signal line in the top metal layer. The considered spiral-structured devices of spiral shunt line sizes were designed, simulated and fabricated. The fabricated BSF is expected to achieve up to 40 dB rejection at microwave stop band with an optimized Q factor.

Publication Date


Project Designation

Graduate Research

Primary Advisor

Guru Subramanyam

Primary Advisor's Department

Electrical and Computer Engineering


Stander Symposium poster

Barium Strontium Titanate Varactor-Tuned Spiral Bandstop Filter for Microwave Applications