Switchable and Tunable BAW Duplexer Based on Ferroelectric Material.

A switchable and tunable bulk acoustic wave (BAW) duplexer for RF applications is presented in this paper. The fabricated BAW duplexer was built on sapphire substrate using solidly mounted resonators. A metal-organic solution deposition technique was used to form resonators with barium strontium titanate (BST) thin film and six layers of silicon dioxide and tantalum oxide as Bragg reflector.

High-Quality-Factor and Low-Temperature-Dependence SMR FBAR Based on BST Using MOD Method.

This paper presents the design, fabrication, and experimental evaluation of switchable and tunable thin-film bulk acoustic wave (BAW) resonators and filters with metal-organic solution deposited barium strontium titanate (BST) for radio-frequency (RF) applications. The switchability and tunability of these devices come from utilizing the electrostrictive effect of ferroelectric materials such as BST with the application of an external dc bias voltage. The BAW resonators and filters in this paper were fabricated on a high-resistivity silicon substrate as a solidly mounted resonator structure with eight layers of silicon dioxide and tantalum pentoxide as a Bragg reflector.

PLL jitter reduction by utilizing a ferroelectric capacitor as a VCO timing element.

Ferroelectric capacitors have steadily been integrated into semiconductor processes due to their potential as storage elements within memory devices. Polarization reversal within ferroelectric capacitors creates a high nonlinear dielectric constant along with a hysteresis profile. Due to these attributes, a phase-locked loop (PLL), when based on a ferroelectric capacitor, has the advantage of reduced cycle-to-cycle jitter.

Tunable ferroelectric capacitor-based voltage-controlled oscillator.

Ferroelectric capacitors made from Ba(1-0.5)Sr0.5TiO3 (BST) are applied as varactors in tunable, high-frequency circuit applications.

Polarization-switching D/A converter.

This paper describes a novel digital-to-analog (D/A) conversion technique, which uses the analog quantity polarization as a D/A conversion medium. It can be implemented by CMOS capacitors or by ferroelectric capacitors, which exhibit strong nonlinearity in charge versus voltage behavior. Because a ferroelectric material inherently has spontaneous polarization and generally has a large dielectric constant, the effective capacitance of a ferroelectric capacitor is much larger than that of a CMOS capacitor of the same size.

Modeling of charge switching in ferroelectric capacitors.

To simulate charge switching in ferroelectric capacitors, a pair of exponential growth and decay currents is mapped to the process of polarization reversal. This is based on the fact that these exponential currents [i.e.