Design and implementation of combline bandpass tunable filter using barium-strontium-titanate thin-film capacitors. Issue 183 (2nd September 2017)

• Record Type: Journal Article
• Authors: Liu, Lang; Chen, Hongwei; Zhang, Jihua; Tan, Yu; Wang, Wenjun; Yang, Chuanren
• Is Part Of: Integrated ferroelectrics. Issue 183(2017)
• Page Start: 126
• Page End: 135
• Publication Date: 2017-09-02
• Subjects: BST -- sapphire substrate -- combline filter -- capacitors -- tunable filter; Ferroelectric devices -- Periodicals; Integrated circuits -- Periodicals; 537.244805
• DOI: 10.1080/10584587.2017.1376973
• Languages: English
• ISSNs: 1058-4587

Abstract

ABSTRACT: The design, fabrication and microwave properties of tunable fifth-order combline bandpass filter using etched barium-strontium-titanate (BST) thin films on sapphire (0001) substrates were investigated. At 1 MHz and 1000 kV/cm electric field, the dielectric tunability, the remanent polarization (2 P r ) and the coercive electric field (2 E C ) of BST films were 45.96%, 2.26 µC/cm 2 and 81.83 kV/cm, respectively. The loss tangent was 1.36% at zero electric field. After the BST parallel plate capacitors characterization, BST capacitors were loaded at the end of parallel coupled resonators in the design of the tunable filter. With the application of 20 V DC voltage, the center frequency of the filter varied from 1.17 GHz to 1.34 GHz which corresponds to a relative shift of 13.5%.