Wireless Biomedical Applications Research Articles

A Single-Stage Dual-Output Regulating Rectifier With Sequential Pulse Frequency Modulation Control for Wireless Biomedical Applications

A Single-Stage Dual-Output Regulating Rectifier With Sequential Pulse Frequency Modulation Control for Wireless Biomedical Applications

Design of Enhanced Skin-Implantable Patch Antenna for Wireless Biomedical Applications

Design of Enhanced Skin-Implantable Patch Antenna for Wireless Biomedical Applications

Efficient Biomedical Signal Security Algorithm for Smart Internet of Medical Things (IoMTs) Applications

Due to the rapid development of information and emerging communication technologies, developing and implementing solutions in the Internet of Medical Things (IoMTs) field have become relevant. This work developed a novel data security algorithm for deployment in emerging wireless biomedical sensor network (WBSN) and IoMTs applications while exchanging electronic patient folders (EPFs) over unsecured communication channels. These EPF data are collected using wireless biomedical sensors implemented in WBSN and IoMTs applications. Our algorithm is designed to ensure a high level of security for confidential patient information and verify the copyrights of bio-signal records included in the EPFs. The proposed scheme involves the use of Hahn’s discrete orthogonal moments for bio-signal feature vector extraction. Next, confidential patient information with the extracted feature vectors is converted into a QR code. The latter is then encrypted based on a proposed two-dimensional version of the modified chaotic logistic map. To demonstrate the feasibility of our scheme in IoMTs, it was implemented on a low-cost hardware board, namely Raspberry Pi, where the quad-core processors of this board are exploited using parallel computing. The conducted numerical experiments showed, on the one hand, that our scheme is highly secure and provides excellent robustness against common signal-processing attacks (noise, filtering, geometric transformations, compression, etc.). On the other hand, the obtained results demonstrated the fast running of our scheme when it is implemented on the Raspberry Pi board based on parallel computing. Furthermore, the results of the conducted comparisons reflect the superiority of our algorithm in terms of robustness when compared to recent bio-signal copyright protection schemes.

Orientation-Insensitive Multi-Antenna Reader for Wireless Biomedical Applications.

This paper presents a multi-antenna external reader system that enables orientation insensitive communication with implantable medical devices (IMDs) for wireless biomedical applications. The proposed system consists of a circular array with six loop antennas. The antenna placement and orientations are determined by analyzing the near-field magnetic field variations of the loop antenna. The proposed system is first simulated using HFSS electromagnetic simulation software. Our simulations show that the received power at the proposed external reader with six antennas only varies about 5 dB for any given orientation of the implanted antenna, which is highly significant compared to the 20-35 dB variation with a single external antenna. Here, we select the antenna which provides the largest coupling between the IMD to receive/transmit signals. A prototype of the proposed multi-antenna external reader is then implemented using custom-designed PCBs that interconnect loop antennas, transceiver ICs, and commercially-available circuit components. A custom PCB with a miniaturized loop antenna is used to emulate an implantable device. Based on measurement results, the received power in the external reader only varies about 3 dB when the miniaturized antenna rotates with respect to the x-axis. These measurements show good agreement with the simulated reader.

Graphene Nanomaterials-Based Radio-Frequency/Microwave Biosensors for Biomaterials Detection.

In this paper, the advances in radio-frequency (RF)/microwave biosensors based on graphene nanomaterials including graphene, graphene oxide (GO), and reduced graphene oxide (rGO) are reviewed. From a few frontier studies, recently developed graphene nanomaterials-based RF/microwave biosensors are examined in-depth and discussed. Finally, the prospects and challenges of the next-generation RF/microwave biosensors for wireless biomedical applications are proposed.

Technology for 3D System Integration for Flexible Wireless Biomedical Applications.

This paper presents a new 3D bottom-up packing technology for integrating a chip, an induction coil, and interconnections for flexible wireless biomedical applications. Parylene was used as a flexible substrate for the bottom-up embedding of the chip, insulation layer, interconnection, and inductors to form a flexible wireless biomedical microsystem. The system can be implanted on or inside the human body. A 50-μm gold foil deposited through laser micromachining by using a picosecond laser was used as an inductor to yield a higher quality factor than that yielded by thickness-increasing methods such as the fold-and-bond method or thick-metal electroplating method at the operation frequency of 1 MHz. For system integration, parylene was used as a flexible substrate, and the contact pads and connections between the coil and chip were generated using gold deposition. The advantage of the proposed process can integrate the chip and coil vertically to generate a single biocompatible system in order to reduce required area. The proposed system entails the use of 3D integrated circuit packaging concepts to integrate the chip and coil. The results validated the feasibility of this technology.

Design and Optimization of a Low Power Pressure Sensor for Wireless Biomedical Applications

A blood pressure sensor suitable for wireless biomedical applications is designed and optimized. State-of-the-art blood pressure sensors based on piezoresistive transducers in a full Wheatstone bridge configuration use low ohmic values because of relatively high sensitivity and low noise approach resulting in high power consumption. In this paper, the piezoresistance values are increased in order to reduce by one order of magnitude the power consumption in comparison with literature approaches. The microelectromechanical system (MEMS) pressure sensor, the mixed signal circuits signal conditioning circuitry, and the successive approximation register (SAR) analog-to-digital converter (ADC) are designed, optimized, and integrated in the same substrate using a commercial 1 μm CMOS technology. As result of the optimization, we obtained a digital sensor with high sensitivity, low noise (0.002 μV/Hz), and low power consumption (358 μW). Finally, the piezoresistance noise does not affect the pressure sensor application since its value is lower than half least significant bit (LSB) of the ADC.

Feasibility of Energy-Autonomous Wireless Microsensors for Biomedical Applications: Powering and Communication.

In this review, biomedical-related wireless miniature devices such as implantable medical devices, neural prostheses, embedded neural systems, and body area network systems are investigated and categorized. The two main subsystems of such designs, the RF subsystem and the energy source subsystem, are studied in detail. Different application classes are considered separately, focusing on their specific data rate and size characteristics. Also, the energy consumption of state-of-the-art communication practices is compared to the energy that can be generated by current energy scavenging devices, highlighting gaps and opportunities. The RF subsystem is classified, and the suitable architecture for each category of applications is highlighted. Finally, a new figure of merit suitable for wireless biomedical applications is introduced to measure the performance of these devices and assist the designer in selecting the proper system for the required application. This figure of merit can effectively fill the gap of a much required method for comparing different techniques in simulation stage before a final design is chosen for implementation.

Self-Sampled All-MOS ASK Demodulator for Lower ISM Band Applications

An all-MOS ASK demodulator with a wide bandwidth for lower industrial, scientific and medical (ISM) band applications is presented. The chip area is reduced without using any passive element. It is very compact to be integrated in a system-on-chip for wireless biomedical applications, particularly in biomedical implants. Because of low area cost and low power consumption, the proposed design is also easy to integrate in other mobile medical devices. The self-sampled loop with a MOS equivalent capacitor compensation mechanism enlarges the bandwidth, which is more than enough to be adopted in any application using lower ISM bands.

Resource-aware secure ECG healthcare monitoring through body sensor networks

Real-time medical data about patients' physiological status can be collected simply by using wearable medical sensors based on a body sensor network. However, we lack an efficient, reliable, and secure BSN platform that can meet increasing needs in e-healthcare applications. Many such applications require a BSN to support multiple data rates with reliable and energyefficient data transmission. In this article we propose a secure and resource-aware BSN architecture to enable real-time healthcare monitoring, especially for secure wireless electrocardiogram data streaming and monitoring. A cross-layer framework was developed based on unequal resource allocation to support efficient biomedical data monitoring. In this framework important information (e.g., critical ECG data) is identified, and extra resources are allocated to protect it. Furthermore, BSN resource factors are exploited to guarantee a strict requirement of real-time performance. In this work we integrate biomedical information processing and transmission in a unified platform, where secure data transmission in a BSN proceeds with energy efficiency and minimum delay. In particular, we present a wearable ECG device consisting of small and low-power healthnode sensors for wireless three-lead ECG monitoring. Experimental and simulation results demonstrate that the proposed framework can support real-time wireless biomedical monitoring applications.

Design and implementation of an optimised wireless pressure sensor for biomedical application

This paper presents design and implementation of a wireless pressure sensor system for biomedical application. The system consists of a front-end Micro-Electro- Mechanical System (MEMS) sensing capacitor along with an optimised MEMS-based oscillator for signal conditioning circuit. In this design, vertical fringed comb capacitor is employed due to the advantages of smaller area, higher linearity and larger full scale change in capacitance compared to parallel plate counterparts. The MEMS components are designed in Coventorware design suite and their Verilog-A models are extracted and then imported to Cadence for co-simulation with the CMOS section of the system using AMI 0.6-micron CMOS process. In this paper, an optimisation method to significantly reduce the system power consumption while maintaining the system performance sufficient is also proposed. A phase noise optimisation approach is based on the algorithm to limit the oscillator tail current. Results show that for the pressure range of 0---300 mmHg the device capacitance range of 1.31 pF --- 1.98 pF is achieved which results in a frequency sweep of 2.54 GHz --- 1.95 GHz. Results also indicate that a 42% reduction of power consumption is achieved when the optimisation algorithm is applied. This characteristic makes the sensor system a better candidate for wireless biomedical applications where power consumption is the major factor.