This work describes a bio-potential acquisition system for portable ubiquitous healthcare applications using flexible polydimethylsiloxane dry electrodes (FPDEs) and a low-power recording circuit. This novel FPDE used Au as the skin contact layer, which was made using a CO2 laser and replica method technology. The FPDE was revised from a commercial bio-potential electrode with a conductive snap using dry electrodes rather than wet electrodes that proposed reliable and robust attachment for the purpose of measurement, and attaching velcro made it wearable on the forearm for bio-potential applications. Furthermore, this study proposes a recording device to store bio-potential signal data and provides portability and low-power consumption for the proposed acquisition system. To acquire differential bio-potentials, such as electrocardiogram (ECG) signals, the proposed recording device includes a low-power front-end acquisition chip fabricated using a complementary metal-oxide-semiconductor (CMOS) process, a commercial microcontroller (MSP430F149), and a secure digital (SD) card for portable healthcare applications. The proposed system can obtain ECG signals efficiently and are comfortable to the skin. The power consumption of the system is about 85 mW for continuous working over a 3 day period with two AA batteries. It can also be used as a compact Holter ECG system.
A novel S-shaped quad-band planar inverted-F antenna (PIFA) is proposed for implantable biotelemetry in the Medical Device Radiocommunications Service (MedRadio) band (401–406 MHz), Wireless Medical Telemetry Service (WMTS) band (1427–1432 MHz), and industrial, scientific, and medical (ISM) bands (433-434 MHz and 2.4–2.4835 GHz). The proposed antenna reveals compact dimension of 254 mm3(10×10×2.45 mm3) and is composed of three substrates and a superstrate, which are constructed from an S-shaped radiator (layer 1) and two twin radiators of spiral structures (layer 2 and layer 3). The optimal antenna characteristics were measured in the ground pork skin, and the measured bandwidths are 150 MHz for the MedRadio and ISM bands (433 MHz), 52 MHz for the WMTS band, and 102 MHz for the ISM band (2.4 GHz), respectively. The characteristics of proposed antenna are enough to support the applications of implantable body area networks (BAN) for biotelemetry and can completely cover main available frequency bands of BAN for biotelemetry below 3 GHz.
In this study, thin films of CaBi4Ti4O15with preferential crystal orientation were prepared by the chemical solution deposition (CSD) technique on a SiO2/Si substrate. The films consisted of a crystalline phase of bismuth-layer-structured dielectric. The as-deposited CaBi4Ti4O15thin films were crystallized in a conventional furnace annealing (RTA) under the temperature of 700 to 800°C for 1min. Structural and morphological characterization of the CBT thin films were investigated by X-ray diffraction (XRD) and field-emission scanning electron microscope (FE-SEM). The impedance analyzer HP4294A and HP4156C semiconductor parameters analyzer were used to measurement capacitance voltage (C-V) characteristics and leakage current density of electric field (J-E) characteristics by metal-ferroelectric-insulator- semiconductor (MFIS) structure. By the experimental result the CBT thin film in electrical field 20V, annealing temperature in 750°C the CBT thin film leaks the electric current is 1.88x10-7A/cm2and the memory window is 1.2V. In addition, we found the strongest (119) peak of as-deposited thin films as the annealed temperature of 750°C
An implantable antenna for the applications of biomedical telemetry has been widely studied in the modern medical science. The purpose of this study is to design and fabricate an implantable antenna which exhibits enhanced bandwidth (25%) and miniaturization for the use of implantation. In this letter, the microwave dielectric ceramic (MgTa1.5Nb0.5O6) substrate which possesses high dielectric constant (εr = 28) and high quality factor is used as the substrate of the implantable antenna, a CPW-fed monopole dual spiral structure is adopted as the antenna pattern and fabricated by the print-screening technique. The effects of shape, length, size, and thicknesses of the proposed antenna would be evaluated and investigated in this letter. In addition, the center frequency is required to conform to the band (402 ~ 405 MHz) provided by Medical Implant Communication Services (MICS). From the experimental results of the proposed antenna immersed in phantom fluid, the optimum antenna exhibits a miniaturized volume of 288 mm3, bandwidth of 134 MHz (33%), return loss 16.32 db at 404 MHz, the SAR of 142 W/Kg, and gain of 16 db, respectively.
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