An official website of the United States government
The next evolutionary step in biological signal monitoring will be enabled by wireless communication. Low power and cost-efficient wireless transceivers are currently being employed for implantable medical devices (IMDs), in addition to military and civilian applications such as monitoring, surveillance, and home automation. The major goal of this paper is to do a thorough and realistic link budget analysis for an implantable wireless transceiver operating in the 3–5 GHz ultrawideband frequency with a link distance of 2 m (which includes 10 mm of brain tissue layer and 1.99 m of air medium), data rate of 100 Mbps with On-Off keying (OOK) modulation, and a minimum receiver sensitivity of −58.01 dBm. The proposed power budget analysis is particularly well suited for distributed brain implant applications as it models the path loss including the tissue layer without compromising the spectrum regulation imposed by the Federal Communications Commission (FCC) for UWB communication.
more »
« less
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.
more »
« less
- Award ID(s):
- 1763709
- PAR ID:
- 10366012
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 13
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
This paper presents the design, implementation, and experimental evaluation of a wireless biomedical implant platform exploiting the magnetoelectric effect for wireless power and bi-directional communication. As an emerging wireless power transfer method, magnetoelectric is promising for mm-scaled bio-implants because of its superior misalignment sensitivity, high efficiency, and low tissue absorption compared to other modalities [46, 59, 60]. Utilizing the same physical mechanism for power and communication is critical for implant miniaturization, but low-power magnetoelectric uplink communication has not been achieved yet. For the first time, we design and demonstrate near-zero power magnetoelectric backscatter from the mm-sized implants by exploiting the converse magnetostriction effects. The system for demonstration consists of an 8.2-mm3 wireless implantable device and a custom portable transceiver. The implant's ASIC interfacing with the magnetoelectric transducer encodes uplink data by changing the transducer's load, resulting in resonance frequency changes for frequency-shift-keying modulation. The magnetoelectrically backscattered signal is sensed and demodulated through frequency-to-digital conversion by the external transceiver. With design optimizations in data modulation and recovery, the proposed system archives > 1-kbps data rate at the 335-kHz carrier frequency, with a communication distance greater than 2 cm and a bit error rate less than 1E-3. Further, we validate the proposed system for wireless stimulation and sensing, and conducted ex-vivo tests through a 1.5-cm porcine tissue. The proposed magnetoelectric backscatter approach provides a path towards miniaturized wireless bio-implants for advanced biomedical applications like closed-loop neuromodulation.more » « less
-
Mid-infrared microscopy is an important tool for biological analyses, allowing a direct probe of molecular bonds in their low energy landscape. In addition to the label-free extraction of spectroscopic information, the application of broadband sources can provide a third dimension of chemical specificity. However, to enable widespread deployment, mid-infrared microscopy platforms need to be compact and robust while offering high speed, broad bandwidth, and high signal-to-noise ratio. In this study, we experimentally showcase the integration of a broadband, high-repetition-rate dual-comb spectrometer (DCS) in the mid-infrared range with a scanning microscope. We employ a set of 1-GHz mid-infrared frequency combs, demonstrating their capability for high-speed and broadband hyperspectral imaging of polymers and ovarian tissue. The system covers 1000 cm−1 at νc = 2941 cm−1 with 12.86 kHz spectra acquisition rate and 5 µm spatial resolution. Taken together, our experiments and analysis elucidate the trade-off between bandwidth and speed in DCS as it relates to microscopy. This provides a roadmap for the future advancement and application of high-repetition-rate DCS hyperspectral imaging.more » « less
-
Sub-terahertz (THz) wireless communication links require low-SWaP (size, weight, and power) software defined radio (SDR) modems to achieve efficient and reliable data transmission. This research presents the design, development, and experimentation of an SDR system operating in the 135-150 GHz frequency range, utilizing simple I/Q modulation techniques such as differential binary phase shift keying (DBPSK). The system integrates advanced components, including Virginia Diodes (VDI) 110-170 GHz compact upconverter (CCU) and compact downconverter (CCD), high-gain lens horn antennas from Anteral (40 dBi), and the Xilinx RF-SoC ZCU-111 for real time DSP. A 500 MHz IF is implemented on RF-SoC with baseband bandwidth 64 MHz and data rate 64 Mbps via DBPSK modulation. For 20 dBm transmit power at 147 GHz, the nearfield SNR was measured to be 55 dB at 1m lens-to-lens separation for a baseband of 64 MHz. Simulation models of propagation predict 64 Mbps is possibly viable at up to 2 km in a point-to-point connection for a BER of < 10−3. The SDR was realized on the Xilinx PYNQ platform, offering a user-friendly interface while being adaptable to high data rate applications. This digital design is particularly suited for deployment in scenarios such as vehicle-to-vehicle communication, backhaul networks, and data center level interconnects. The research explored challenges related to synchronization, signal integrity, and environmental sensitivity, which are critical for maintaining reliable communication in a 147 GHz channel. A real-time text messaging application demonstrated correct operation of the PYNQ modem.more » « less
-
Communication over large-bandwidth millimeter wave (mmWave) spectrum bands can provide high data rate, through utilizing highgain beamforming vectors (briefly, beams). Real-time tracking of such beams, which is needed for supporting mobile users, can be accomplished through developing machine learning (ML) models. While computer simulations were used to show the success of such ML models, experimental results are still limited. Consequently in this paper, we verify the effectiveness of mmWave beam tracking over the open-source COSMOS testbed. We particularly utilize a multi-armed bandit (MAB) scheme, which follows reinforcement learning (RL) approach. In our MAB-based beam tracking model, the beam selection is modeled as an action, while the reward of the algorithm is modeled through the link throughput. Experimental results, conducted over the 60-GHz COSMOS-based mobile platform, show that the MAB-based beam tracking learning model can achieve almost 92% throughput compared to the Genie-aided beams after a few learning samples.more » « less
