BAW Resonator Surface Sizing for Low Intermodulation Noise
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Solution Overview
Problem
Conventional bulk acoustic wave (BAW) resonators exhibit nonlinear transmission characteristics at high signal powers, leading to harmonic generation and intermodulation noise, which interfere with signal reception due to voltage-dependent static capacitance affecting the piezoelectric layer's thickness.
Innovation Solution
The resonator's surface area is optimized to enhance linearity, with specific target levels for second- and third-order intercept points, and the resonator can be arranged above an acoustic mirror or cutout in a carrier substrate, allowing for improved power handling and reduced power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional BAW resonators are used with high signal power, then power handling capability is improved, but nonlinearity increases leading to harmonic generation and intermodulation noise
Solution Approach 1:
The patent applies parameter changes by optimizing the resonator surface area to a specific value or range that improves linearity. By changing the geometric parameter (surface area) of the resonator, the power density is reduced, which in turn reduces the nonlinearity and harmful intermodulation products while maintaining power handling capability.
2Reliability
If resonator surface area is increased to reduce power density and improve linearity, then device area increases
Solution Approach 1:
The patent determines an optimal resonator surface area value that balances linearity improvement with area constraints. Through parameter optimization, the resonator achieves sufficient linearity for the intended application while minimizing the required surface area, thus resolving the contradiction between reliability and device size.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The optimized resonator design achieves high linearity over a wide dynamic range, reducing intermodulation noise and harmonic distortion, making it suitable for multiband devices like mobile radios with improved power handling and reduced noise interference.
Implementation Method 1
A BAW resonator comprises a piezoelectric layer that is arranged between two electrodes
Implementation Method 2
The BAW resonator can be arranged above an acoustic mirror formed on a carrier substrate
Data Source
AI summary
An electroacoustic resonator includes a resonator area for propagating an acoustic wave and a resonator surface area configured so that, when an input signal power of 0 dBm is applied at a resonant frequency fr, power density in the resonator area does not exceed 40 dBm/m2. An electroacoustic resonator includes a resonator surface area configured so that a critical input signal power PIIPn at an nth-order intercept point IPn is at least 80 dBm for n=2 and/or 80 dBm for n=3.