Acoustic wave filter based on periodically poled lithium niobate

Area of Science:

• Materials Science
• Electrical Engineering
• Acoustics

Background:

• Standard surface or bulk acoustic wave devices face limitations in compactness.
• There is a growing need for advanced RF passive transducers.
• Lithium niobate is a promising material for acoustic wave devices.

Purpose of the Study:

• To develop a compact RF passive transducer.
• To investigate periodically poled ferroelectric domains in lithium niobate for acoustic filters.
• To demonstrate a novel acoustic band-pass filter design.

Main Methods:

• Fabrication of periodically poled transducers (PPTs) on lithium niobate wafers.
• Excitation of elliptical and longitudinal acoustic modes.
• Design and fabrication of a PPT-based acoustic band-pass filter.
• Experimental measurement of the filter's electrical response and transfer function.

Main Results:

• Successful fabrication of PPTs operating from 20 to 650 MHz.
• Achieved phase velocities of approximately 3800 m/s (elliptical) and 6500 m/s (longitudinal).
• Demonstrated the feasibility of a PPT-based acoustic band-pass filter.

Conclusions:

• Periodically poled transducers offer a viable alternative to interdigital transducers for acoustic filters.
• The developed PPT-based filter shows promise for compact RF applications.
• Further research is needed to address the limitations of this method.