Lithium Niobate Piezoelectric Micromachined Ultrasonic Transducers for high data-rate intrabody communication

Abstract

In recent years, there has been an increased interest in continuous monitoring of patients and their Implanted Medical Devices (IMDs) with different wireless technologies such as ultrasounds. This paper demonstrates a high data-rate intrabody communication link based on Lithium Niobate (LN) Piezoelectric Micromachined Ultrasonic Transducers (pMUTs). The properties of the LN allow to activate multiple flexural mode of vibration with only top electrodes. When operating in materials like the human tissue, these modes are merging and forming a large communication bandwidth. Such large bandwidth, up to 400 kHz, allows for a high-data rate communication link for IMDs. Here we demonstrate a full communication link in a tissue phantom with a fabricated LN pMUT array of 225 elements with an area of just 3 by 3 mm square, showing data-rates up to 800 kbits/s, starting from 3.5 cm and going up to 13.5 cm, which covers the vast majority of IMDs.

Fabrication and DC-Bias Manipulation Frequency Characteristics of AlN-Based Piezoelectric Micromachined Ultrasonic Transducer

“…The overlap of the frequency response curves of the PMUT arrays can be clearly observed. If PMUTs modulated with different bias voltages are reasonably coupled together, the bandwidth of PMUTs can be increased to a great extent [ 9 , 27 , 31 ], as shown in Figure 4 b. The fabricated PMUT device has a −6 dB bandwidth of 6.59 kHz.…”

“…An ultrasound imaging system can provide real-time, high-resolution images, and it is a more affordable medical imaging solution than magnetic resonance imaging and computed tomography. Ultrasonic imaging has also been widely used in other areas of research beyond medical applications, including rangefinders [ 3 , 4 ], fingerprint sensing [ 5 , 6 ], fluid density sensing [ 7 , 8 ], communication links [ 9 ], underwater 3D imaging [ 10 , 11 ], nondestructive testing [ 12 ], and wireless power supply for implantable microdevices [ 13 ]. As one of the typical ultrasonic imaging devices, piezoelectric micromechanical ultrasound transducers (PMUTs) are particularly attractive due to their affordability, compact size, and compatibility with Complementary Metal Oxide Semiconductor (CMOS) manufacturing processes [ 5 , 7 ].…”

“…Hence, piezoelectric materials play a primary role in the performance of PMUT devices. Among the most studied piezoelectric materials, such as PZT [ 6 , 15 ], AlN [ 5 ], AlScN [ 4 ], ZnO [ 16 ], PVDF [ 17 ], and LiNbO3 [ 9 , 18 ], AlN is a competitive candidate due to the excellent compatibility between CMOS and MEMS micromachining. To further improve the performance of the transmit and receive sensitivity of a PMUT, the structure of the PMUT must be optimized.…”

“…As the key performance parameters of PMUTs, the quality factor ( ) and −6 dB BW are especially vital to the application of ultrasonic imaging. Pop et al [ 9 ] designed PMUT arrays with different sizes of top electrodes based on X-cut LiNbO3 that included serial elements centered on different resonant frequencies. These frequencies are so closely spaced that they can cover the extensive desired bandwidth.…”

Synthesis of CaNb2O6 with a Rynersonite-like Structure: Morphology, Rietveld Refinement, Optical, and Vibrational Properties

“…The study of niobium-based oxides, such as pyrochlores, perovskites, and columbites, has led to numerous applications in energy storage, , photocatalysis, , piezoelectricity, − optics, and magnetism . One important member of this family is Calcium Niobate – CaNb 2 O 6 .…”