Simplified thin film resonator model for high order filters application (original) (raw)
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Transmission Line Based Modeling of Thin Film Bulk Acoustic Wave Resonators and Filters
Thin Film Bulk Acoustic Wave technology is a promising candidate for manufacturing miniaturized high performance filters for GigaHertz range. An accurate and at the same time easy to use circuit model for the thin film resonator is needed to provide a simulation tool for designers. In the work encompassed by this paper a transmission line based model that can be used to extract material parameters of the multiple layers comprising the resonator is described. The model was implemented with APLAC ® circuit simulation software.
Film bulk acoustic resonator finite element model in active filter design
2014
Film bulk acoustic resonators (FBARs) are becoming increasingly requested as an element of high-performance bandpass filters for modern microwave communication systems due to its inherent advantages at high frequencies. Active filter design using FBAR allows realizing of a wider range of characteristics. The FBAR active filter design process is related with the optimization of multiple parameters including filter architecture, biasing of active elements, impedance matching and also the topology and structure of resonators. Obtaining of filter's frequency characteristics with high selectivity and smooth phase response is only possible using high-precision models of resonators. The purpose of this work is to propose a three-dimensional finite element model (FEM) of a FBAR for further integration into the computer-aided filter design system. The simulation results of the proposed solution are compared with a frequently used modified Butterworth- Van-Dyke (mBVD) model to designate the significance of changes in the output filter characteristics arising from the application of 3D piezoelectric resonator model.
Design and Analysis of Film Bulk Acoustic Resonator(FBAR) Filter for RF Applications
International journal of radio frequency identification & wireless sensor networks, 2012
The RF band pass filters are important for wireless communication applications. They can be realized using Thin Film Bulk Acoustic Resonator (TFBAR).TFBAR is designed using Aluminium Nitride (AlN) and electrodes of piezoelectric material are made with Platinum (Pt).Various modelling techniques has been used for realizing three layered TFBAR structure. Modified Butter worth-van Dyke model (MBVD) is one used for numerical simulation of AlN film and thin electrodes. The result shows that Lm, Cm, Rm and Co model is perfectly applicable for predicting the response of TFBAR. The proposed design is realized by connecting three series and two shunt FBARs in ladder configuration. In the present work, the filter has been designed for a bandwidth of 270 MHz at-3 dB. The minimum insertion loss of-0.9 dB and return loss of-25 dB are obtained for VSWR ≤ 2 at resonance frequency.
FILM BULK ACOUSTIC WAVE RESONATOR IN RF FILTERS
Film Bulk Acoustic Resonator (FBAR) is widely used as a RF filter in advanced wireless communication system because of its high-Quality Factor (Q) and low inband losses. FBAR is also widely used as a sensor for biomedical and physical sensing. This paper describes the basic concepts of FBAR, device architecture, and the topology used to design the filter. Furthermore, we have proposed the design of 3D-FBAR based on cavity device architecture which can be used to design a RF-filter. In this design, aluminum (Al) is used as a top as well as for the bottom electrode the top electrode is hexahedron in shape, aluminum nitride (AlN) as a piezoelectric and silicon (Si) is used as a substrate. The designed model is to analyses maximum pressure of FBAR in its operating region, the resonant frequency fr which is 2.76 GHz and anti-resonant frequency fa which is 2.78 GHz and Qfactor is 730.
A laminated plate theory for high frequency, piezoelectric thin-film resonators
Journal of Applied Physics, 1993
A high frequency, piezoelectric, laminated plate theory is developed and presented for the purpose of modeling and analyzing piezoelectric thin-film resonators and filters. The laminated plate equations are extensions of anisotropic composite plate theories to include piezoelectric effects and capabilities for modeling harmonic overtones of thickness-shear vibrations. Two-dimensional equations of motion for piezoelectric laminates were deduced from the three-dimensional equations of linear piezoelectricity by expanding the mechanical displacements and electric potential in a series of trigonometric function, and obtaining stress resultants by integrating through the plate thickness. Relations for handling the mechanical and electrical effects of platings on the top and bottom surfaces of the laminate are derived. A new matrix method of correcting the cutoff frequencies is presented. This matrix method could also be used to efficiently correct the cutoff frequencies of any nth order ...
The selection of a proper metal electrode, piezoelectric layer, optimization of coupling coefficient and Q value of film bulk acoustic resonators (FBAR) are the key issues in the design and performance enhancement of a FBAR based bandpass filters. The optimum effective coupling coefficient is determined by studying the effect of various metal electrodes and by varying the thickness ratio of electrode and piezoelectric layer. In this paper, we present the optimum performance analysis of film bulk acoustic resonator in terms of effective coupling coefficient and spurious resonances. The optimum effective coupling coefficient of 7.1% is obtained with tungsten electrode with thickness ratio of 0.1. The spurious resonances have been minimized by different frame-like FBAR structures and simulated using COMSOL Multiphysics design tool. The boundary frame FBAR shows the best balance of performance by effectively suppressing the spurious resonances along with no reduction in effective coupling coefficient. These optimized film bulk acoustic wave resonators can be utilized for the implementation of high performance bandpass filters.
2012
The RF band pass filters are important for wireless communication applications. They can be realized using Thin Film Bulk Acoustic Resonator (TFBAR).TFBAR is designed using Aluminium Nitride (AlN) and electrodes of piezoelectric material are made with Platinum (Pt).Various modelling techniques has been used for realizing three layered TFBAR structure. Modified Butter worth‐van Dyke model (MBVD) is one used for numerical simulation of AlN film and thin electrodes. The result shows that Lm, Cm, Rm and Co model is perfectly applicable for predicting the response of TFBAR. The proposed design is realized by connecting three series and two shunt FBARs in ladder configuration. In the present work, the filter has been designed for a bandwidth of 270 MHz at ‐3 dB. The minimum insertion loss of ‐0.9 dB and return loss of ‐25 dB are obtained for VSWR ≤ 2 at resonance frequency.
1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027), 1999
The parameters of the KLM and Mason's equivalent circuits in the thickness mode are presented to include dielectric, elastic and piezoelectric loss. The models are compared under various boundary conditions with and without acoustic layers to the analytical solutions of the wave equation. We show that in all cases equivalence is found between the analytical solution and the KLM and Mason's equivalent circuit models. It is noted that in order to maintain consistency with the linear equations of piezoelectricity and the wave equation care is required when applying complex coefficients to the models. The effect of the piezoelectric loss component on the power dissipated in the transducer is presented for loaded and unloaded transducers to determine the significance of the piezoelectric loss to transducer designers. The effect of the piezoelectric loss on the insertion loss was found to be small.
Prototype Design of a Thin-Film Bulk Acoustic-Wave Resonator by the Finite Element Method
IEEE Transactions on Magnetics, 2000
A thin film bulk acoustic wave resonator (FBAR) used in the RF frequency region of a few gigahertz is considered and its impedance is evaluated by using a harmonic analysis with the three-dimensional finite element method. In particular, the spurious characteristics caused by variations in the electrode area, as well as all the resonant modes and the mode shapes are analyzed. A design procedure is presented by using a prediction software tool. An experimental prototype is built and the measured results are compared to the numerical ones.