Tunable Lumped Element Filters With BST Thin-Film Varactors
- Resource Type
- Conference
- Authors
- Lourandakis, Errikos; Schmidt, Matthias; Seitz, Stefan; Weigel, Robert
- Source
- 2008 38th European Microwave Conference Microwave Conference, 2008. EuMC 2008. 38th European. :1691-1694 Oct, 2008
- Subject
- Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
Fields, Waves and Electromagnetics
Aerospace
Communication, Networking and Broadcast Technologies
Photonics and Electrooptics
Binary search trees
Transistors
Varactors
Tunable circuits and devices
Thin film circuits
Circuit topology
Circuit optimization
Prototypes
Band pass filters
Tuning
- Language
Tunable lumped element filter topologies are discussed based on ferroelectric thin-film varactors. The design methodology for the proposed filter topologies relies on already known techniques and is enhanced with the tuning functionality by introducing the Barium-Strontium-Titanate (BST) varactors. Prototype circuits of a lowpass and a bandstop filter were fabricated and the measurement results showed good agreement to the corresponding calculated data. The lowpass prototype achieves a continuous tuning range from 1.5GHz to 1.9 GHz. The highest measured passband insertion loss is about 4 dB and the input matching is better than -15dB for all bias states. The implemented bandstop filter allows a continuous tuning of the notch frequency from 1.5GHz to 2.1GHz with a minimum attenuation of 17 dB.