Mode-Selective Electrode Configuration for Multifrequency Operation in PMUTs: Microfabrication and Characterization
Bibliographic record
Abstract
Multi-frequency operation in ultrasonic transducers balances the trade-off between resolution and penetration depth in ultrasonic imaging. Single top-electrode PMUTs couple strongly to the fundamental mode but weakly to higher-order modes because uniform electrode coverage does not conform to the higher-mode strain profile. Dual concentric ring-and-disk (C–C) electrodes access multiple modes yet reduce fundamental-mode coupling due to misalignment between the segmented coverage and the fundamental strain profile. In this work a circular square (C-Sq) dual top electrode is introduced to strengthen coupling in both the fundamental and higher order modes for multifrequency operation. The configuration pairs a circular outer electrode with a square inner electrode on a circular membrane. The topology aligns with the strain profiles of the fundamental and a selected higher mode enabling mode selective excitation by electrode switching. The proposed C-Sq dual electrode design and reference single electrode and dual electrode concentric ring and disk (C-C) devices were fabricated using the PiezoMUMPs multi-user MEMS process for fair comparison. Electrical impedance analysis, laser doppler vibrometry, and acoustic measurements show a 37% increase in fundamental mode electromechanical coupling relative to C-C dual electrode PMUT and a 27% improvement for the higher mode relative to single electrode PMUTs. Membrane displacement increases by 67% and acoustic pressure at the fundamental resonance is enhanced by 13%. The proposed C-Sq PMUT supports efficient, mode selective multifrequency operation for biomedical imaging and sensing.[2025-0152]
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".