Analysis of general planar waveguides with N segments

Pocksteiner, N.; Jungwirth, Mario; Kovacs, G.; Weigel, Robert

doi:10.1109/ultsym.2000.922525

Cited by 11 publications

(4 citation statements)

References 2 publications

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“…Incorporation of the spatial discretization (18) and (19) into the weak formulation results in a semidiscrete finite element system of linear equations, expressed in the following matrix form [9] (22) (23) where is the effective mass matrix and {</}", [v]" and [β]" are the approximations of d(t"), d(t") and d(t") in the finite element nodes, respectively. Furthermore, n+1 and n denote the new and the old time step index.…”

Section: Discretizationmentioning

confidence: 99%

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Accurate and Efficient Modeling of SAW Structures

Hofer¹,

Jungwirth²,

Lerch³

et al. 2001

Frequenz

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By way of two examples it is demonstrated that basic field theory concepts may be successfully applied to model anisotropic microacoustic phenomena which occur in the design of surface acoustic wave (SAW) devices. A new 3D finite element method (FEM) scheme incorporating multigrid (MG) algorithms is presented which allows for the first time a complete and accurate simulation of the propagation of surface acoustic waves in 3D. On the other hand, the feasibility of a new scalar 2D wave theory method called profile propagation method (PPM) is demonstrated and experimentally verified which enables a very efficient simulation of SAW phenomena. Both methods compromise accuracy for efficiency on a specific level of abstraction. Therefore, both techniques are indispensable for the design of complete SAW devices which usually is done employing network-theory methods. ÜbersichtAnhand zweier Beispiele wird die erfolgreiche Anwendung neuer numerischer Verfahren zur Modellierung mikroakustischer Phänomene demonstriert, welche beim Design von Oberflächenwellenbauelementen (OFW-Bauelementen) auftreten. Mittels einer 3D-Rnite-Elemente-Methode (FEM), in die ein schneller, iterativer Multigrid-Löser (MG-Loser) integriert wurde, war es erstmals möglich, die Ausbreitung von Oberflächenwellen unter Berücksichtigung aller Randeffekte zu berechnen. Des weiteren wird auf der Basis der Wellentheorie eine effiziente, zweidimensionale OFW-Designmethode namens Profile-Propagation-Method (PPM) vorgestellt. Diese ermöglicht ebenfalls eine effiziente Berechnung der Effekte, welche bei der Ausbreitung von Oberflächenwellen wesentlich sind. Beide Methoden legen den notwendigen Kompromiß zwischen Schärfe der Beschreibung einerseits und Recheneffizienz andererseits auf einer spezifischen, dem jeweiligen Problem angepaßten Stufe fest. Beide Methoden sind für den Entwurf kompletter OFW-Bauelemente unverzichtbar.Für die Dokumentation OFW-Bauteile / Modellierung / Finite-Elemente-Methode / Multigrid-Methode / Profile-Propagation-Methode

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Section: Discretizationmentioning

confidence: 99%

“…The calculation of the normalization factors C of bound, semi-bound and radiation modes (C, C) is outlined in [19].…”

Section: Radiation Modesmentioning

confidence: 99%

Accurate and Efficient Modeling of SAW Structures

Hofer¹,

Jungwirth²,

Lerch³

et al. 2001

Frequenz

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“…Typically, a one-port resonator in SiO 2 -covered LiNbO 3 displays a series of distinct transversal modes above the resonance frequency. When such resonators are used in filter designs without taking any countermeasures, the transversal modes lead to unacceptable passband ripples [2], [3]. In the previous work [1], we have demonstrated that a 2D periodic array with patches on electrodes can successfully get rid of undesired modes within the frequency band of k y = 0, π p T , where p T is the transversal pitch of the periodic array.…”

Section: Introductionmentioning

confidence: 98%

Advanced 2D periodic array and full transversal mode suppression

Yoon

Mayer

Ebner³

et al. 2013

2013 IEEE International Ultrasonics Symposium (IUS)

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In this work, we present an improved version of the 2D periodic array from [Yoon et al, IUS2012, [1]]. Using a 2D P-matrix simulation tool, required COM (coupling of modes) parameters and periodic Δv/v waveguide parameters were optimized for desired 2D behavior. On this basis, the fine-tuned real geometries were determined. In the analysis of such a resonator, we introduce a novel approach in analogy to a multiple quantum well structure in solid state physics. It turns out that the optimized 2D periodic array with geometry variations fully suppresses all unwanted transversal modes within a certain bandwidth. Besides, prominent peaks by the transversal periodicity are also distinctively suppressed at the frequencies where the wavelength of the y-components of the transversal modes is comparable to the transversal pitch (p T ), i.e., near ky = π p T . Therefore the 2D periodic array on the electrodes can be readily employed in designing SAW filters in SiO 2 -covered LiNbO 3 with excellent performance.

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“…Due to the finite aperture of the acoustic track of a resonator, various diffraction effects may occur. Acoustic tracks forming good waveguides show transversal modes propagating under certain angles with respect to the main propagation direction giving rise to undesired peaks in the pass-and the stopband [3], [4]. This inherent attribute deteriorates the characteristics of the frequency response in SAW filters.…”

Section: Introductionmentioning

confidence: 99%

Two dimensional periodic array of reflection centers on electrodes in SAW resonators

Yoon

Mayer

Ebner

et al. 2012

2012 IEEE International Ultrasonics Symposium

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Periodic arrays of metallic patches on the electrodes of a "Rayleigh-type SAW resonator" are investigated to suppress undesired modes above resonance frequency. Both, the metallization ratio(ηt) and the period( ‫۾‬ ‫ۺ‬ ) of the patches in transversal direction, were varied. Simulations were performed employing the well established 2D P-matrix model. A well-designed periodic array is capable to suppress all transversal modes within the frequency band for = ቂ, ቃ. By evaluation of the overlap integral of the excitation and mode profile, and consequently, the analysis of the single mode contribution to the excitation strength, it is demonstrated that higher modes are responsible for remaining spurious peaks in the resonator's frequency response. The analysis of the contribution of the transversal modes to the admittance provides insight how the ∆/ waveguide, formed by the areas with and without patches, can be engineered to suppress bound and leaky continuum modes.

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Analysis of general planar waveguides with N segments

Cited by 11 publications

References 2 publications

Accurate and Efficient Modeling of SAW Structures

Accurate and Efficient Modeling of SAW Structures

Advanced 2D periodic array and full transversal mode suppression

Two dimensional periodic array of reflection centers on electrodes in SAW resonators

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