Body Channel Research Articles

Analytical Evaluation of MOSFET Secondary Effects

Abstract. MOSFET is a field effect transistor that can be used in a wide range of analog and digital circuits. It has the advantages of low power consumption, high speed and high integration. Its abbreviation is MOS. During the operation of MOS tubes, there are some secondary effects that cannot be ignored in circuit analysis and there is a research gap in analyzing and evaluating these effects. Therefore, in this paper, we will analyze and evaluate the body effect, channel length modulation effect, subthreshold conductivity effect, and short channel effect among the secondary effects by reviewing the related literature and give some methods to minimize the impact of secondary effects on circuits. In this study, the secondary effects of MOS tubes are discussed in depth. In the combing of previous related studies, the above several common secondary effects of MOS tubes are summarized and inductively analyzed, and the effects of reduced body effect and channel length modulation effect on circuits are summarized and evaluated. These results provide important theoretical support and practical guidance for MOSFET research.

(Invited) Mobility Enhancement Technology of Extremely-Thin Body Ge-on-Insulator Channel Mosfets

An extremely thin body (ETB) channel is mandatory for scaled nano-sheet structures to realize continuous miniaturization of CMOS devices. Here, mobility booster technologies to maintain high channel mobility are strongly needed, because surface roughness scattering significantly reduces mobility in such ETB channels. From this viewpoint, Ge-On-Insulator (GOI) or SiGe-On-Insulator (SGOI) channels are promising because of the low electron and hole effective mass along channel directions. It is theoretically shown that (111) GOI n-MOSFETs can hold high electron mobility even in the body thickness down to 2 nm. Thus, (111) GOI structures and n-MOSFETs are fabricated, and the electrical characteristics are studied. For p-MOSFETs, on the other hand, (110) surface orientation and application of compressive strain are still effective in boosting hole mobility in ETB channels. Here, (110) asymmetric compressive strain SGOI p-MOSFETs are experimentally demonstrated, and the body thickness dependencies of the effective mobility are examined.

A Battery-Free Neural-Recording Chip Achieving 5.5 cm Fully-Implanted Depth by Galvanically-Switching Passive Body Channel Communication

A Battery-Free Neural-Recording Chip Achieving 5.5 cm Fully-Implanted Depth by Galvanically-Switching Passive Body Channel Communication

Design and performance analysis of manchester coder-based body channel communication using FPGA

In general, the Body Channel Communication (BCC) is used to transmit human physiological signals over vast distances. Also, the Error-correcting codes can detect and rectify faults in long-range data transmission. Data is encoded in a predetermined manner for secure transmission. In this paper, a Manchester encoding-based high throughput architecture is proposed for a body channel communication system with a low-power operation mode. Further, the Manchester encoder is designed for high throughput performance with a low complexity architecture, and an analog front-end processing circuit which includes two stage pre-amplifiers. Also, the transmission rate on the BCC transceiver side is boosted by the maximum Consecutive Identical Digit (CID), which is limited by Manchester codes. The Manchester code format is generated by encoding the sensed data. Additionally, a full gain buffer is used to reduce data loss and hardware overhead. Results demonstrate that the suggested Manchester encoder is implemented in 90 nano meter (nm) technology, and the 10 Megabits per second (Mbps) data rate is obtained with a configurable operating frequency ranging from 1 to 100 Megahertz (MHz).

Low-power body-coupled transceiver for miniaturized body area networks

As wearable devices continue to proliferate, seamlessly integrating them into wireless body-area networks (WBANs) becomes increasingly crucial. Body-coupled communication (BCC) emerges as a promising WBAN technology, utilizing the human body itself as a transmission channel. This paper presents a novel BCC transceiver designed for efficiency and miniaturization. The proposed transceiver prioritizes reliable data transmission with a convolutional encoder. It leverages a simple direct digital synthesizer (DDS) for frequency shift keying (FSK) modulation, minimizing chip area. At the receiver, a Viterbi decoder (VD) ensures accurate data recovery. This design shines in its resource efficiency. It occupies less than 1% of an Artix-7 FPGA, operates at 268.77 MHz with a mere 111 mW power consumption, and achieves a remarkable data rate of 13.78 Mbps. This translates to a hardware efficiency of 44.46 Kbps/slice, surpassing existing transceivers. Moreover, the BCC transceiver exhibits a stellar bit error rate (BER) of over 10⁻⁷ under realistic body channel conditions. Overall, this work presents a highly efficient BCC transceiver with significant improvements in chip area, power consumption, and data rate compared to existing designs. This paves the way for practical and miniaturized WBAN solutions for future wearable applications.

Implantable pH Sensing System Using Vertically Stacked Silicon Nanowire Arrays and Body Channel Communication for Gastroesophageal Reflux Monitoring.

Silicon nanowires (SiNWs) are emerging as versatile components in the fabrication of sensors for implantable medical devices because of their exceptional electrical, optical, and mechanical properties. This paper presents a novel top-down fabrication method for vertically stacked SiNWs, eliminating the need for wet oxidation, wet etching, and nanolithography. The integration of these SiNWs into body channel communication (BCC) circuits was also explored. The fabricated SiNWs were confirmed to be capable of forming arrays with multiple layers and rows. The SiNW-based pH sensors demonstrated a robust response to pH changes, and when tested with BCC circuits, they showed that it was possible to quantize based on pH when transmitting data through the human body. This study successfully developed a novel method for SiNW fabrication and integration into BCC circuits, which could lead to improvements in the reliability and efficiency of implantable medical sensors. The findings demonstrate significant potential for bioelectronic applications and real-time biochemical monitoring.

A 2m-Range 711μW Body Channel Communication Transceiver Featuring Dynamically-Sampling Bias-Free Interface Front End.

Body Channel Communication (BCC) utilizes the body surface as a low-loss signal transmission medium, reducing the power consumption of wireless wearable devices. However, the effective communication range on the human body is limited in the state-of-the-art BCC transceivers, where the signal loss between the body surface and the BCC receiver remains one of the main bottlenecks. To reduce the interface loss, a high input impedance is desired by the BCC receiver, but the DC-biasing circuits decrease the input impedance. In this work, a dynamically-sampling IFE is proposed to eliminate the DC voltage bias, resulting in a 90kΩ high input impedance and a 94dB RF-IF conversion gain to reduce the interface loss in long-range BCC applications. The BCC transceiver chip is fabricated in 55nm CMOS process, taking a die area of 0.123mm2. Measured results show that the chip extends the BCC range to 2m for both the forward and backward paths, where the transmitter and receiver consume 711μW power in total.

A Re-configurable Body Channel Transceiver towards Wearable and Flexible Biomedical Sensor Networks.

Body channel communication (BCC) has become a promising candidate in wireless body area networks (WBAN) due to its advantages in energy efficiency and security. However, BCC transceivers face two challenges: diverse application requirements and varying channel conditions. To overcome these challenges, this paper proposes a re-configurable architecture for BCC transceivers (TRXs), whose key parameters and communication protocols can be software-defined (SD) according to the requirements. In the proposed TRX, the programmable direct-sampling receiver (RX) is a combination of a programmable low-noise amplifier (LNA) and a fast-convergent successive approaching register analog-to-digital converter (SAR ADC), to achieve simple but energy-efficient data reception. The programmable digital transmitter (TX) is essentially implemented by a 2-bit DAC array to transmit either wide-band carrier-free signals like 4-level pulse amplitude modulation (PAM-4) or non-return-to-zero (NRZ) or narrow-band carrier-based signals like on-off keying (OOK) or frequency shift keying (FSK). The proposed BCC TRX is fabricated in a 180-nm CMOS process. Through an in-vivo experiment, it achieves up to 10-Mbps data rate and 119.2 pJ/bit energy efficiency. Moreover, the TRX is able to communicate under long-distance (1.5 m) and body-shielding conditions by switching its protocols, which shows the potential to be deployed in all categories of WBAN applications.

A 60Mb/s -64dBm Body Channel Communication Transceiver Utilizing Manchester Code.

Body channel communication (BCC) which uses the human body as the communication channel has shown better energy efficiency and security compared with air channel communication. This article presents a simple, stable, and high transfer rate BCC technique using Manchester encoding, capacitive termination, and digital signal transfer operation. Manchester encoding is used to realize the spectrum migration of the baseband signal, and digital signal transmission simplifies system design and improves signal stability. The chip is fabricated in 65-nm technology. The experimental results show that the proposed transceiver achieved the highest data rates of 60 Mbps and the measured RX sensitivity is -64dBm. And the chip is also used to set up a multi-sensor nodes communication system to realize the data interaction between one hub and eight slave sensors utilizing the human body as the communication medium.

Machine learning-based output prediction of negative capacitance tunnel-FET

ABSTRACT Machine learning-based prediction of the output characteristics of a negative capacitance (NC) double gate (DG) Tunnel FET (TFET) (NC DG TFET) has been demonstrated in this paper. On current (ION), OFF current (IOFF) and sub-threshold slope (SS) have been predicted for different values of the body thickness (TSi), oxide thickness (TOX) and channel length (LCh) and the work function (WF). Random Forest Regression (RFR) model is used in the ML framework to explore the device characteristics. A total of 5444 simulated data has been generated by using the SILVACO ATLAS tool. After pre-processing the data, RFR-ML has been applied to obtain maximum accuracy. Root means square error (RMSE) (~0.34), R2 score (~0.965) and accuracy (~98.51%) parameter have been used as the figures of merit (FOM) to judge the efficiency of the proposed model with respect to the state-of-the-art literature. Besides, with higher accuracy, the model is capable of predicting the data within a few seconds compared to the few hundred hours using TCAD tools. This fast and accurate design strategy will surely be efficacious for the present VLSI industries.

The possible contribution of [formula omitted] meson decay into X(3872) and ϕ(1020)

In this paper, we present the branching ratio and polarization fraction of two body decay of Bs0 to the vector mesons ϕ(1020) and X(3872) in which the X(3872) meson can be considered as an intermediate resonance in the final decay Bs0→J/ψπ+π−ϕ(1020). For this aim, the naive factorization approach is used to calculate the decay amplitude with the different helicities due to the combination of polarization states of two mesons X(3872) and ϕ(1020). Within the framework of the factorization approach, we find the branching fraction for the two body channel of Bs0→X(3872)ϕ(1020)=(6.31±0.01)×10−5 and also Br(X(3872)→J/ψπ+π−) and Br(X(3872)→J/ψπ+π−)Br(Bs0→X(3872)ϕ(1020)) are calculated which are in well agreement with CMS collaboration data. Furthermore, we estimate the decay width of resonance X(3872) into final states J/ψπ+π− which is within the range of experimental data. By these results and available experimental data, we render the branching ratio of decays B+ and Bs0 into X(3872)K+ and X(3872)K0, respectively. Also, in the nonleptonic two body decay of Bs0→X(3872)ϕ(1020), the direct and indirect CP-violating asymmetries are estimated to indicate the potential role of the such decays to measure CP-violation.

Cooperative Body Channel Communications for Energy-Efficient Internet of Bodies

The Internet of Bodies (IoB) is a network formed by wearable, implantable, ingestible, and injectable smart devices to collect physiological, behavioral, and structural information from the human body. Thus, the IoB technology can revolutionize the quality of human life by using these context-rich data in myriad smart-health applications. Radio frequency (RF) transceivers have been typically preferred due to their availability and maturity. However, for most RF standards (e.g., Bluetooth low energy), the highly radiative omnidirectional RF propagation (even at the lowest settings) reaches tens of meters of coverage, thereby reducing energy efficiency, causing interference and co-existence issues, and raising privacy and security concerns. On the other hand, body channel communication (BCC) confines low-power and low-frequency (10 kHz–100 MHz) signals to the human body, leading to more secure and efficient communications. Since energy efficiency is one of the critical design parameters of IoB networks, this article focuses on energy-efficient orthogonal body channel access (OBA) and non-OBA (NOBA) schemes with and without cooperation. To this aim, three main BCC topologies are presented: 1) point-to-point channel; 2) medium access channel; and 3) broadcast channel. These topologies are then used as building blocks to create IoB networks relying on OBA and NOBA schemes for downlink (DL) and uplink (UL) traffic. For all schemes and traffic directions, optimal transmit power and phase time allocations are derived in closed-form, which is essential to reduce energy consumption by eliminating computational power. The closed-form expressions are further leveraged to obtain maximum network size as a function of data rate requirement, bandwidth, and hardware parameters.

Design of high‐speed data transfer turbo code for body channel communication transceivers

SummaryIn this work, a digital differential transmitter based on low‐power wireless compensation transceiver for body channel communication (BCC) is proposed. Further, the proposed transceiver is composed of Touch Status Detection Unit (TSDU), Wireless Status Compensation Unit (WSCU), and a reconfigurable preamplifier. Initially, the human body channel environment for wireless communication is investigated based on properties from 1 to 100 MHz. Further, the turbo code‐based encoding scheme is used to encode the data before transferring the data on the transmitter side. Also, the proposed error‐correcting parallel turbo decoder using a modified step‐by‐step algorithm is presented. The turbo code‐based decoding scheme is used to recover the error‐free transmitted data at the receiver side. Results demonstrate that the proposed BCC transceiver is designed using 90 nm CMOS technology and it is observed that the proposed BCC transceiver has utilized an area of 600mm2. Also, the maximum data rate achieved by a proposed BCC transceiver was 100 Mbps, and the overall transceiver power consumption is 0.42 mW, and energy for communication is 0.02 nj/b.

An PPG signal and body channel based encryption method for WBANs

With the rapid development of the Internet of Medical Things (IoMT) in recent years, Wireless Body Area Network (WBAN) has become a hot topic in the scientific and industrial community, since it defines a novel network architecture for medical and healthcare circumstances in IoT and loMT. Considering that unauthorized data tampering and information leakage in WBAN may cause life-threatening issues, Data security is an important technical support to ensure the smooth implementation of WBAN. Due to the characteristics of the WBAN system, the traditional wireless communication data security method is not suitable for WBAN because of the high complexity and high cost. This paper adopts the Photoplethysmography (PPG) signal feature and the channel characteristic values from the WBAN system to calculate the base key, then generates the key sequence for data encryption of WBAN through Linear Feedback Shift Register (LFSR). Experimental results show that this data security method has the advantages of less resource consumption, low computational complexity, and dynamic key update.

Understanding the Role of Magnetic and Magneto-Quasistatic Fields in Human Body Communication.

With the advent of wearables, Human Body Communication (HBC) has emerged as a physically secure and power-efficient alternative to the otherwise ubiquitous Wireless Body Area Network (WBAN). Whereas the most investigated HBC modalities have been Electric and Electro-quasistatic (EQS) Capacitive and Galvanic, recently Magnetic HBC (M-HBC) has been proposed as a viable alternative. Previous works have investigated M-HBC through application points-of-view, without exploring its fundamental working principle. In this paper, a ground up analysis is performed to study the possible effects and contributions of the human body channel in M-HBC over 1kHz to 10 GHz, by electromagnetic simulations and supporting experiments. The results show that while M-HBC can be successfully operated as a body area network, the human body itself plays a minimal or negligible role in its functionality. For Magneto-quasistatic (MQS) HBC (frequencies less than ∼30 MHz), the body is transparent to the quasistatic magnetic field. Conversely for higher frequencies, the conductivity of human tissues attenuates Magnetic HBC fields due to induced Eddy currents, preventing the body to support efficient waveguide modes. With this conceptual understanding developed, different modes of operations of MQS HBC are outlined for both high impedance capacitive and 50Ω termination cases, and their performances are compared with EQS HBC for similar sized devices, over varying distances between TX and RX. The resulting report presents a fundamental understanding towards M-HBC operation and its contrast with EQS HBC, aiding HBC device designers to make educated design decisions, depending on application scenarios.

Climatology and nutrient fluxes in the Tagus estuary: A coupled model application

Rivers are responsible for the main transport of nutrients from land to estuaries and coastal areas. Understanding the fate of these anthropogenic inputs and their impacts on estuaries and adjacent marine ecosystems is essential for the protection of coastal waters. Here, the 3D MOHID hydrodynamic model coupled with a biogeochemical model was used to determine seasonal nutrient fluxes between areas of the Tagus estuary. For this purpose, the estuary was divided into boxes, which allowed to evaluate nutrients (and phytoplankton) exchanges between areas, to identify source and sink zones, to estimate the amount of nutrients exported to the coastal zone adjacent to the estuary, and to understand the recycling capacity of this estuarine system. Globally, for all nutrients and seasons, the highest net fluxes were observed in the main and central body of the estuary. The differences observed in the flux budget for each box and for all nutrients are mostly related to variations in the seasonal abundance of phytoplankton, which is much higher in Spring/Summer than in the rest of the year due to the higher seawater temperature and irradiance. During these seasons the high temperatures also promoted the fast mineralization of organic matter along the water column and in the sediment. For all seasons, an export of nutrients and phytoplankton from upstream to downstream was observer at the surface, and from the most confined areas of the southern margin into the central body and main channel of the estuary, whilst the opposite was observed in the bottom layers. Nevertheless, surface fluxes were always higher than those recorded at depth, indicating that the estuary exported nutrients to the coast, all year round. For 2020 it was estimated that 52%, 88% and 65% of the ammonium, nitrate, and phosphate, respectively, that entered the estuary from both rivers and wastewater treatment plants were exported to the adjacent coast. The amount of nutrients exported to the coastal area is closely related to river discharge, being much higher in flood years than in dry years, particularly for nitrate.

An Implantable Neuromorphic Sensing System Featuring Near-sensor Computation and Send-on-Delta Transmission for Wireless Neural Sensing of Peripheral Nerves.

This paper presents a bio-inspired event-driven neuromorphic sensing system (NSS) capable of performing on-chip feature extraction and "send-on-delta" pulse-based transmission, targeting peripheral-nerve neural recording applications. The proposed NSS employs event-based sampling which, by leveraging the sparse nature of electroneurogram (ENG) signals, achieves a data compression ratio of >125×, while maintaining a low normalized RMS error of 4% after reconstruction. The proposed NSS consists of three sub-circuits. A clockless level-crossing (LC) ADC with background offset calibration has been employed to reduce the data rate, while maintaining a high signal to quantization noise ratio. A fully synthesized spiking neural network (SNN) extracts temporal features of compound action potential signals consumes only 13 μW. An event-driven pulse-based body channel communication (Pulse-BCC) with serialized address-event representation encoding (AER) schemes minimizes transmission energy and form factor. The prototype is fabricated in 40-nm CMOS occupying a 0.32-mm2 active area and consumes in total 28.2 μW and 50 μW power in feature extraction and full diagnosis mode, respectively. The presented NSS also extracts temporal features of compound action potential signals with 10-μs precision.

Enabling the Internet of Bodies Through Capacitive Body Channel Access Schemes

The Internet of Bodies (IoB) is an imminent extension of the vast Internet of Things (IoT) domain, where wearable, ingestible, injectable, and implantable smart objects form a network in, on, and around the human body. The highly radiative nature of radio-frequency (RF) IoB devices unnecessarily extends the coverage range beyond the human body, which reduces energy efficiency, causes co-existence and interference issues, and exposes sensitive personal data to security threats. Alternatively, capacitive body channel communication (BCC) confine signal transmission to the human body to reduce signal leakage, experience less propagation loss, and reach pJ/b energy efficiency levels. Therefore, capacitive BCC is a key enabler to reach the ultimate design goals of ultra low power, high throughput, and small form-factor IoB devices. Albeit these attractive features, the communication and networking aspects of the capacitive BCC are not thoroughly explored yet. Therefore, this article proposes orthogonal and nonorthogonal capacitive body channel access schemes with or without cooperation among the IoB nodes. In order to address the Quality of Service (QoS) demand scenarios of different IoB applications, we present and formulate the max–min rate, max-sum rate, and QoS sufficient operational regimes, and then provide closed-form and numerical solution optimal power and phase time allocations. Extensive numerical results are analyzed to compare the performance of orthogonal and nonorthogonal schemes with and without cooperation for various design parameters under prescribed QoS regimes. The obtained results show that capacitive body channel access schemes can provide several Mb/s rates even at low transmission powers ranging between −60 and −90 dBm. Moreover, the cooperative schemes are shown to be effective to avoid performance degradation caused by increasing network size, low transmission power, and poor channel quality.

The Internet of Bodies: The Human Body as an Efficient and Secure Wireless Channel

The Internet of Bodies (IoB) is a network of smart objects placed in, on, and around the human body, allowing for intra- and inter-body communications. This position article aims to provide a glimpse into the opportunities created by implantable, injectable, ingestible, and wearable IoB devices. The article starts with a thorough discussion of application-specific design goals, technical challenges, and enabling communication standards. We discuss why the highly radiative nature of radio frequency (RF) systems results in inefficient communication due to over-ex-tended coverage, causing interference and becoming susceptible to eavesdropping. Alternatively, body channel communication (BCC) uses the human body as a transmission medium by coupling harmless electrical signals, yielding secure and efficient communication thanks to better channel conditions and lower signal leakage than over-the-air RF systems. Numerical results show that various BCC topologies can respectively reach 8–12 Mb/s and 1.5-3 Mb/s max-sum and max-min rates with 1 MHz bandwidth and -30 dBm transmission power, which is three orders of magnitude lower than safety limits. Moreover, the BCC is capable of accommodating tens of IoB nodes up to 1 Mb/s rates, which is sufficient for most IoB applications. Furthermore, as the cyber and biological worlds meet, security risks and privacy concerns take center stage, leading to a discussion of multi-faceted legal, societal, ethical, and political issues related to technology governance.

A Visible Human Data-Based Whole-Body Model for Investigating the Transmission Attenuation of Intrabody Communication

Intrabody communication (IBC) is a promising approach for realizing information transmission among various wearable or implantable devices within bodyNET. The existing IBC studies are limited to the local or abstract geometric channel model, which is limited to providing efficient channel characteristics for the various transmitting scenarios. The aim of this article is to reconstruct a whole-body model with anatomical features and combine the field-circuit model for investigating the human channel characteristics. A visible human data (VHD) is established by segmentation and 3-D reconstruction of layered tissues. The transmission attenuation was simulated and analyzed through the finite element method. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">In vivo</i> experiments and phantom experiments were implemented to validate the simulation results. For the on-body communication, the transmission attenuation of the short distance was similar to the low-pass filter’s amplitude-frequency characteristics. For the implantable communication, the consistency coefficient of the attenuation between in-body to on-body and on-body to in-body was higher than 98%, indicating that the body channel is bidirectional. This work provides a repeatable and verified VHD-based whole-body model for the human channel attenuation investigation. It is an essential step for the further development of IBC, such as the transceiver design and the multinodes’ protocol for bodyNET.