Design of a miniaturized x-band chebyshev band-pass filter based on BST thin film

Date of Award


Degree Name

M.S. in Electrical Engineering


Department of Electrical and Computer Engineering


Advisor: Guru Subramanyam


This thesis reports the design procedures of X-band (8-10GHz) Chebyshev band-pass filter based on high dielectric constant Barium Strontium Titanate (BST) thin film. Design procedures will be illustrated from fundamental formulas and lumped element circuits to real electromagnetic (EM) geometry. The Chebyshev band-pass filter is achieved by two coupled hairpin resonators formed by a coplanar waveguide feed-line structure. The designed Chebyshev band-pass prototype has 3 ripples (3rd order) and 1dB insertion loss in pass-band. The miniaturized dimension is 2400μm by 2420μm. The center frequency is 10GHz. The bandwidth is 1GHz. The Q factor is 19.5. Three samples were fabricated. Two of them were based on sapphire substrate without BST layer, the other is based on the high resistivity silicon substrate with 0.25μm thick BST thin film. Measured non-BST band-pass filter has 5dB insertion loss in pass-band and 1.3GHz bandwidth. The center frequency of sample having BST thin film is shifted 1GHz to lower frequency while maintaining the same frequency characteristic in pass-band.


Ferroelectric thin films Research, Electric filters, bandpass Design and construction

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Copyright © 2012, author