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Published on: February 4, 2018
Linear frequency tuning of SAW resonators
1Westinghouse Electr. Corp., Baltimore, MD.
Summary
This study introduces a new method for tuning surface acoustic wave (SAW) resonator oscillators using varactor diodes and inductors. This technique achieves significantly larger linear frequency tuning ranges compared to traditional phase shifters.
Area of Science:
- Electrical Engineering
- Acoustics
- Materials Science
Background:
- Surface Acoustic Wave (SAW) resonators are crucial for frequency stabilization in oscillators.
- Traditional frequency tuning methods often use voltage-controlled phase shifters, which have limitations.
Purpose of the Study:
- To develop a novel impedance transformation technique for linear frequency tuning of two-port SAW resonators.
- To improve upon existing methods for achieving wider tuning ranges in SAW resonator-stabilized oscillators.
Main Methods:
- Design of abrupt junction varactor diode-inductor networks.
- Utilizing impedance transformation techniques to modify resonator motional impedance.
- Employing varactor diode parallel inductance for a linear reactance-voltage relationship.
Main Results:
- Achieved significantly larger tuning ranges compared to phase shifter approaches.
- Demonstrated linear frequency tuning of approximately 400 ppm for a 320-MHz SAW resonator.
- Successfully adapted a technique previously used for bulk wave quartz crystal resonators.
Conclusions:
- The varactor diode-inductor network provides an effective method for linear frequency tuning of SAW resonators.
- This approach offers superior tuning range capabilities for SAW resonator-stabilized oscillators.
- The technique shows promise for applications requiring precise and wide-range frequency control.
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