Technical Insights: Solving Engineering Challenges in Piezoelectrics

Drawing from my 30-year career in materials science and my tenure as President of TRS Technologies, I have authored 21 patents and 75 publications that have fundamentally advanced the field of piezoelectricity. The information below provides a curated selection of these works, categorized by the specific engineering challenges they addressed.

All Patents and Publications Referenced Below are Drawn from Wes Hackenberger's Resume

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Developing and Commercializing Advanced Piezoelectric Material Systems at Scale

Engineering Challenge:

Piezoelectric performance gains are meaningless if materials cannot be produced consistently, characterized reliably, and integrated into real devices. Many organizations struggle to move beyond a single material formulation or laboratory-scale capability, limiting design flexibility and long-term supply reliability.

Solution:

I led the commercialization of 12 piezoelectric product lines across soft and hard material systems, including PZT and PMN-PT ceramics and single crystals. This included 9 PZT-based ceramic compositions and 3 PMN-PT–based ceramic systems, as well as advanced PMN-PT and PIN-PMN-PT single-crystal materials engineered for giant piezoelectric response. I lead development a versatile portfolio optimized for varying dielectric, thermal, and mechanical requirements, enabling designers to select materials based on specific device needs.

Key Technical Outcomes:

Commercialization of multiple piezoelectric ceramic families with controlled property ranges
Development of complementary single-crystal systems for high-performance applications
Material platforms supporting sensors, actuators, transducers, and energy storage devices

Representative Publications:

High Performance Single Crystal Piezoelectrics Applications and Issues — defined practical tradeoffs between ceramic and crystal systems.
Recent developments on high Curie temperature PIN–PMN–PT ferroelectric crystals — expanded operating temperature windows.
Processing and structure–property relationships for fine-grained PZT ceramics — linked manufacturing variables to functional performance.

Representative Patents:

Relaxor-PT Ferroelectric Single Crystals (US 8241519) — defined material systems suitable for commercial implementation.
Method of Making Ternary Piezoelectric Crystals (US, EU, JP) — enabled repeatable manufacturing of advanced crystal materials.
Temperature and Field Stable Relaxor-PT Piezoelectric Single Crystals (US 8907546 / US 9673380) — improved operational robustness.

Stabilizing Single-Crystal Performance for Medical Imaging and Sonar Transducers

Engineering Challenge:

Advanced sonar requires transducers with precise bandwidth and source levels. While relaxor-PT single crystals (like PMN-PT) offer high strain, they are sensitive to temperature and high electric drive fields, which can lead to depolarization or performance degradation in the demanding environments of underwater acoustics.

Solution:

I led research into second and third-generation ternary single crystals, such as PIN- PMN-PT, which significantly increased the phase transition temperature and coercive field compared to binary PMN-PT. By optimizing composition and dopants (like Manganese), we developed materials that maintain high electromechanical coupling while remaining stable under high AC drive fields and varying thermal conditions. This stability allowed for more compact, higher-power sonar systems that outperform legacy PZT ceramic designs.

Key Technical Outcomes:

Enhanced allowable AC drive field levels by 60% through internal bias engineering.
Extended the operating temperature window for rhombohedral crystals to the >110°C range.
Enabled wide-bandwidth, high-source-level sonar transducers.
Enables medical transducers with advanced imaging modes such as harmonic imaging and radiation force induced strain imaging.

Representative Publications:

Advanced Single Crystal Piezoelectric Transducers for Naval Sonar and Medical Ultrasound Applications — reported on unprecedented bandwidth increases.
Field Stability of Piezoelectric Shear Properties in PIN-PMN-PT Crystals —
detailed the mechanics of stabilization under high drive.
PIN–PMN–PT piezoelectric crystals with increased rhombohedral-to-tetragonal phase transition temperature — demonstrated stabilization via composition modifications.

Representative Patents:

Relaxor-PT Ferroelectric Single Crystals (US 8241519) — defined the material systems for stable commercial implementation.
Temperature and Field Stable Relaxor-PT Piezoelectric Single Crystals (US 8907546 / 9673380) — patented methods for operational robustness.
Method of Making Ternary Piezoelectric Crystals (US 7972527, EP 2235762, JP 5281657) — enabled scalable production of stable ternary PIN-PMN-PT compositions

High-Performance Piezoelectric Transducer and Phased Array Development

Engineering Challenge:

High-frequency medical ultrasound and Non-Destructive Evaluation (NDE) systems are often limited by transducer bandwidth, sensitivity, and acoustic efficiency. Traditional dicing-and-filling methods are physically limited by the fragility of ceramic materials at small scales; as frequencies increase, the required element pitch becomes so fine that conventional manufacturing results in low yields, poor uniformity, and high cross-talk.

Solution:

I led the development of Piezoelectric Composite Micromachined Ultrasound Transducer (PC-MUT) technology to overcome these fabrication limits. By combining single-crystal or fine-grained high-density ceramics with advanced microfabrication methods—specifically deep reactive ion etching (DRIE) and photolithography—my team created ultra-fine 1-3 composites with precise sub-wavelength features. This approach optimized material-device integration through refined electrode design and poling configurations, bridging the gap between laboratory-scale prototypes and scalable, reliable commercial manufacturing for high-resolution imaging platforms.

Key Technical Outcomes:

Successfully prototyped 35 MHz 64-element phased arrays with bandwidths exceeding 90%.
Developed single-crystal composite transducers (up to 75 MHz) for high-
resolution C-scan NDE and medical imaging.
Significant reduction in element variability and improved consistency in array manufacturing through low surface defect machining.
Enabled deeper penetration and higher resolution across clinical and industrial NDE imaging platforms.

Representative Publications:

Development of a C-Scan phased array ultrasonic imaging system using a 64-element 35MHz transducer — validated high-frequency single-crystal array technology.
Advanced Piezoelectric Materials for Medical Ultrasound Transducers — demonstrated material-property optimization directly tied to transducer performance.
Single crystal piezoelectric composites for advanced NDT ultrasound — detailed 15 MHz to 75 MHz micromachined composites.
Broad Band Single Crystal Transducer for Contrast Agent Harmonic Imaging — addressed bandwidth and nonlinear imaging requirements.

Representative Patents:

Micromachined Imaging Transducer (US 7622853) — enabled scalable fabrication of high-frequency imaging arrays.
Micromachined Ultrasonic Transducer Arrays (US 8008842 / US 8148877) — defined the architectures for repeatable micromachined manufacturing.
Transverse Mode Multi-Resonant Single Crystal Transducer (US 9070865) — multi-resonant designs for bandwidth extension.

Overcoming Energy Density Limits in Capacitors and Pulsed-Power Materials

Engineering Challenge:

Conventional dielectric and ceramic capacitor technologies face hard limits in achievable energy density, breakdown strength, and reliability under high-field operation. These limitations restrict performance in pulsed-power systems, power conditioning, and compact energy storage applications.

Solution:

I developed and commercialized high-energy-density dielectric and ferroelectric materials that significantly increased stored energy while maintaining reliability under extreme electric fields. This work combined materials engineering, multilayer device design, and breakdown mitigation strategies. In parallel, I worked on shock-discharge and fast depolarization materials capable of generating extremely high voltages under dynamic loading, addressing applications where conventional power electronics are not viable.

Key Technical Outcomes:

High-energy-density multilayer ceramic capacitor
Improved dielectric breakdown performance
Pulsed-power materials capable of rapid energy release
Temperature-stable capacitor behavior

Representative Publications:

Advanced Multilayer Capacitors Using High Energy Density Antiferroelectric Ceramics — device-level design and performance.
High voltage generation with shock-compressed ferroelectrics — characterization of pulsed-power behavior.
High dielectric constant terpolymers for energy storage capacitors — focused on advanced materials for high energy density storage

Representative Patents:

High Energy Density Antiferroelectric Multilayer Ceramic Capacitor (US 7781358 / US 7884042) — multilayer architectures enabling high field operation.
High Energy Density Shock Discharge Materials (US 8821748) — materials engineered for rapid electrical energy release.
High Polarization Energy Storage Components (US 8894765) — oriented structures for improved energy storage efficiency.