A Thin-Film BST Varactor Model for Linear and Nonlinear Circuit Simulations for Mobile Communication Systems

2010 IEEE Radio and Wireless Symposium (RWS)

Gloeckler

et al. 2010

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A new methodology for multiband tunable power amplifiers (PA) using barium-strontium-titanate (BST) varactors is presented. A prototype tunable power amplifier has been developed and its performance is evaluated in context of the upcoming 4G scenario which demands for multimode/multiband power amplifiers capable of operating over multiple frequency bands. The tunable PA requires two tuning voltages at the output matching network as well as an additional tuning voltage for a novel tunable 2 nd harmonic termination. The PA is continuously tunable from 1700 to 2300 MHz, covering multiple bands. Tunable PA measurements with LTE signals show a maximum gain of 27dB with Pmax of 24.1dBm and an EVM of 6% using BST varactors having Q-factors not more then 30 at sub-2GHz frequencies.Index Terms -Tunable, Multiband power amplifier, BST varactors, 4G.

Section: Bst Varactorsmentioning

confidence: 99%

“…1. Comparison between the measured and modeled [8] capacitance of a BST varactor for different bias voltages. Fig.…”

Section: Bst Varactorsmentioning

confidence: 99%

Tunable multiband power amplifier using thin-film BST varactors for 4G handheld applications

Ali

2010 IEEE Radio and Wireless Symposium (RWS)

Gloeckler

et al. 2010

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“…BEHAVIORAL MODEL FOR CIRCUIT SIMULATIONS Designing high performance microwave circuits is impractical without having appropriate models which can be used in commercially available design tools. In this work, we use Agilent's Advanced Design System (ADS) for implementing an equivalent circuit model, as in [6]. The core element of the proposed model is the symbolically defined device (SDD) as it is available in the ADS library.…”

Section: Cantilever Mems Varactormentioning

confidence: 99%

Characterization and Modeling of Continuously Tunable MEMS Varactor

2009 German Microwave Conference

Fischer

Weigel

2009

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In this work a circuit model for a continuously tunable varactor is presented which is based on a microelectromechanical system (MEMS). This behavioral model can be implemented in commercially available simulation tools and allows for complete circuit simulations in terms of small-and large-signal performance, as well as for transient and envelope responses. For the present implementation Agilent's ADS is used but the modeling methodology can be generalized for use in other tools as well. For the MEMS varactor which is investigated in this paper good agreement is obtained between simulated and measured data. The capacitance variation for different tuning voltages as well as the frequency and power dependency of the component are discussed. For a bias voltage range up to 130 V a capacitance tuning ratio of more than 5:1 is obtained. The excellent linearity provided by minimal self actuation effects qualify the component for use in high power applications.

“…This field, given as E=V /d, causes a variation of the permittivity ε r in the BST-film [5] and thus a voltage dependent capacitance. The overall electrical behavior of BST thin-film varactors can be modeled accurately [6], as indicated in Fig. 1.…”

Section: Ferroelectric Thin-film Varactorsmentioning

confidence: 99%

Tunable Lumped Element Filters With BST Thin-Film Varactors

2008 38th European Microwave Conference

Schmidt²,

Seitz³

et al. 2008

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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 1.5 GHz to 1.9 GHz. The highest measured passband insertion loss is about 4 dB and the input matching is better than -15 dB for all bias states. The implemented bandstop filter allows a continuous tuning of the notch frequency from 1.5 GHz to 2.1 GHz with a minimum attenuation of 17 dB.