Reflection and transmission coefficients of SAW in a periodic grating computed by finite element analysis

Bauerschmidt, P.; Lerch, Reinhard; Machui, J.; Ruile, W.; Visintini, G.

doi:10.1109/ultsym.1990.171400

Cited by 19 publications

(5 citation statements)

References 11 publications

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“…This is possible, but not with standard SAW manufacturing processes. Therefore, we decided to use normal fingers, which resulted in linewidths close to 0.3 m. By using the YZ cut of LiNbO and an appropriate metallization height [33], reflection-free IDTs were designed. As can be seen in Fig.…”

Section: Theoretical and Experimental Resultsmentioning

confidence: 99%

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Design, fabrication, and application of precise SAW delay lines used in an FMCW radar system

Reindl

Ruppel²,

Berek³

et al. 2001

IEEE Trans. Microwave Theory Techn.

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An inexpensive frequency-modulated continuous-wave (FMCW) radar system is presented in this paper, which, nevertheless, meets all industrial requirements. The FMCW radar uses a low-cost nonlinear voltage-controlled oscillator (VCO), operating at an IF of 2.45 GHz to generate the frequency modulation of the radar system. This VCO signal is applied twice, first to generate the radar transmitter signal at 24 GHz, and then it is fed to a surface acoustic wave (SAW) delay line. The SAW delay line generates a fixed delay time, which corresponds with a fixed radar distance. Thus, all systematic nonlinearities and stochastic phase errors of the FMCW system can be monitored and, afterwards, can be compensated for in real time. This linearization technique leads to a significant enhancement in dynamic range for a FMCW radar system. For this FMCW system, SAW delay lines with a linear phase characteristic have been designed using a linear optimization program. The delay line consists of two chirped and weighted interdigital transducers. For high volume, low-cost, and high-yield production of the required SAW structures, with linewidths down to 0.3 m, technological improvements had to be achieved, especially in photolithography. Based on these design and fabrication techniques, delay lines at 2.45 GHz operating at the fundamental and third harmonic with bandwidths up to 800 MHz have been realized.

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Section: Theoretical and Experimental Resultsmentioning

confidence: 99%

“…For the delay lines operating at the fundamental harmonic, only normal fingers could be used. To overcome problems with reflections, the rotated cut of LiNbO and an adequate metallization thickness were chosen [33]. The test devices were fabricated using a liftoff process, projection printing, and an I-line wafer stepper.…”

Section: Design Of the Saw Delay Linementioning

confidence: 99%

Design, fabrication, and application of precise SAW delay lines used in an FMCW radar system

Reindl

Ruppel²,

Berek³

et al. 2001

IEEE Trans. Microwave Theory Techn.

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“…The width of the stop band ∆ω is a characteristic measure of the degree of the mechanical reflections caused by the blocks. These parameters can be used in a COM description of the periodic structure (see, e.g., [1], [5], [12], [13]). According to the COM theory, the expression π∆ω/2ω 0 can be interpreted as the reflection coefficient ρ for a single block (Fig.Fig.…”

Section: Numerical Resultsmentioning

confidence: 99%

FFT-based analysis of periodic structures in microacoustic devices

Jakoby

Vellekoop

2000

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Abstract-Periodic structures utilized as transducer or reflector elements play an important role in microacoustic wave devices. Such structures can be described using approximate analytical models. However, to obtain the accuracy required for reliable device simulation, numerical methods have to be employed. In this contribution, we present an efficient numerical approach to calculate the dispersion curves associated with microacoustic modes propagating in periodic structures; the method is demonstrated for the case of Love wave modes. The computational efficiency is related to the utilization of the FFT algorithm in a hybrid Method of Moments (MoM) /Mode-Matching analysis. From the obtained dispersion curves, characteristic parameters such as the stopband width can be obtained which can be used in a coupling-of-modes (COM) model of the structure.

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“…around k 0 = π/p, where the impact of reflections at the obstacles due to constructive and destructive interference is most prominent and leads to characteristic frequency gaps ω in the dispersion characteristics 4 . The size of these gaps is a measure for the reflectivity of a single obstacle [25]; figure 9 (right) shows the dependence on material and geometry parameters for the considered sample structure. We finally note that a related approach, where the field in the blocks is not expanded in eigenmodes but is analyzed using a finite element model, is utilized in [26].…”

Section: Love Wave Sensorsmentioning

confidence: 99%

Efficient semi-numerical analysis of acoustic sensors using spectral domain methods—a review

Jakoby¹

2008

Meas. Sci. Technol.

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Microacoustic sensors often represent a challenge in device modeling as coupled electromechanical fields and piezoelectric media are involved. Due to this complexity and because of the sometimes adverse ratios of characteristic dimensions to the device size (e.g., in the case of thickness shear mode resonators), the successful application of numerical models such as provided by the finite element method is not always possible in an efficient manner. In numerical electromagnetics and in the analysis of surface acoustic wave devices, the spectral domain method has been established as a useful semi-numerical tool allowing the computationally efficient implementation of device models. In recent years, we have successfully applied the method to several problems involving acoustic sensors. In this paper, the foundations of the method are reviewed and its application in the analysis of selected microacoustic sensors is discussed.

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Reflection and transmission coefficients of SAW in a periodic grating computed by finite element analysis

Cited by 19 publications

References 11 publications

Design, fabrication, and application of precise SAW delay lines used in an FMCW radar system

Design, fabrication, and application of precise SAW delay lines used in an FMCW radar system

FFT-based analysis of periodic structures in microacoustic devices

Efficient semi-numerical analysis of acoustic sensors using spectral domain methods—a review

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