Acoustic Wave Filters

Surface Acoustic Wave Filters, Unitary Extensions and Schur Analysis

We study the concept of a mixed matrix in connection with linear fractional transformations of lossless and passive matrix-valued rational functions, and show that they can be parametrized by sequences of elementary chain matrices. These notions are exemplified on a model of a Surface Acoustic Wave filter for which a state-space realization is carried out in detail. The issue of optimal design ...

Development of Acoustic Wave Filters by Using Magnetostrictive Nickel Gratings

Acoustic wave devices have gained enormous interest for sensor applications. In the current practice, the surface acoustic waves are usually generated and measured by piezoelectric transducers. In this work, however, we propose to generate the acoustic waves by using a magnetostrictive transducer using magneticstrictive nickel strip gratings and a sensing coil. The coil encircling the gratings ...

Theoretical and Experimental Studies of Upright Perforated Wave Filters

Liu et al. (1987) proposed a theoretical solution for scattering of waves through a permeable dissipation region. On the basis of bulk dissipation of the incident wave energy, this method is extended to evaluate the reflection and transmission coefficients of waves through a wave filter composed of rows of perforated sheets aligned normally to the direction of wave propagation. The results of t...

Experimental Studies of Wave Transmission through Single Perforated Sheets and Upright Perforated Wave Filters

Quantum wave bandstop filters

We propose and demonstrate, based on the concept of a microwave bandstop filter, two quantum wave bandstop filter structures. Both structures employ nanoscale gates in a heterojunction transistor to induce a quantum cavity connected by two one-dimensional wires. As the electron wavelength is changed by the gate voltage, we observed that, at certain gate voltages, the transmission of electron wa...