Low loss SAW filters utilizing the natural single phase unidirectional transducer (NSPUDT)

Thorvaldsson, T.; Abbott, B. P.

doi:10.1109/ultsym.1990.171324

“…Similarly, the transmission admittance Y 21 (ω) also can be evaluated by interchanging superscript 1 and superscript 2 in equations (8) and (9). We note that in order to consider the refraction effect accurately, the k y components of k (1) , k (2) and k (f ) must be equal to k 0y .…”

Section: Simulation Model Based On Angular Spectrummentioning

confidence: 99%

Frequency response of a focused SAW device based on concentric wave surfaces: simulation and experiment

Wu¹,

Tang²,

Chen³

2005

J. Phys. D: Appl. Phys.

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Focused interdigital transducers (FIDTs) based on concentric wave surfaces can excite surface acoustic wave (SAW) with high intensity, high beamwidth compression ratio and small localized area. In this paper, we developed a model to analyse the frequency response of a SAW device with FIDTs based on concentric wave surfaces. First, we constructed a focused SAW device by adopting a pair of FIDTs shaped as the concentric wave surface. To calculate its frequency response, a simulation model was established based on the 2D SAW filter model, effective permittivity approach and perturbation theory. Further, the focused SAW devices were designed and fabricated via the microelectromechanical system process technique. A good agreement between the simulated and measured results was found. Finally, the frequency responses of focused SAW devices based on concentric wave surfaces were discussed and some attractive features were found, such as less ripples of pass-band and high stop-band rejection. In addition, in comparison with the conventional SAW devices with uniform interdigital transducers, the focused SAW devices are more sensitive to variations in the focal area, instead of the whole delayline region. Accordingly, they are suitable to be applied to detect or manipulate some localized variations, such as acousto-optic or acousto-electric effects.

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“…6 shows the simulated radiation admittances of a natural single phase unidirectional transducer (NSPUDT) for which C r = 10.3 pF and L r = 93.7 nH. The solid curve is the input admittance simulated using the measured data [29] and the energy storage effect D s = 2π; the dashed curve is the input admittance simulated, including the parasitics consisting of a 3.5-nH series inductance and a 0.8-pF parallel capacitance [7]. The radiation conductance has a dual peak.…”

Section: A Input Admittance For Unapodized Transducersmentioning

confidence: 99%

Simulation of Surface Acoustic Wave Devices

Yu

¹

2004

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

0

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The Mason crossed-field circuit model is generalized to simulate apodized interdigital transducers without channel division. The apodized transducer model is based on the transmission line model, and the artificial transformer with different voltage and current coupling ratios is used to independently obtain the transfer function and radiation admittance. In addition, a heuristic expression for transformer current ratios is used to approximate the radiation admittance of apodized transducers. Through comparing with the multichannel model, this unichannel model is illustrated to successfully describe the frequency response of apodized interdigital transducers.

show abstract

“…6 shows the simulated radiation admittances of a natural single phase unidirectional transducer (NSPUDT) for which C r = 10.3 pF and L r = 93.7 nH. The solid curve is the input admittance simulated using the measured data [29] and the energy storage effect D s = 2π; the dashed curve is the input admittance simulated, including the parasitics consisting of a 3.5-nH series inductance and a 0.8-pF parallel capacitance [7]. The radiation conductance has a dual peak.…”

Section: A Input Admittance For Unapodized Transducersmentioning

confidence: 99%

Simulation of surface acoustic wave devices

Yu

¹

2004

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

0

View full text Add to dashboard Cite

The Mason crossed-field circuit model is generalized to simulate apodized interdigital transducers without channel division. The apodized transducer model is based on the transmission line model, and the artificial transformer with different voltage and current coupling ratios is used to independently obtain the transfer function and radiation admittance. In addition, a heuristic expression for transformer current ratios is used to approximate the radiation admittance of apodized transducers. Through comparing with the multichannel model, this unichannel model is illustrated to successfully describe the frequency response of apodized interdigital transducers.

show abstract

Low loss SAW filters utilizing the natural single phase unidirectional transducer (NSPUDT)

Cited by 42 publications

References 9 publications

Frequency response of a focused SAW device based on concentric wave surfaces: simulation and experiment

Frequency response of a focused SAW device based on concentric wave surfaces: simulation and experiment

Simulation of Surface Acoustic Wave Devices

Simulation of surface acoustic wave devices

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