Article

22-pJ/bit Energy-Efficient 2.4-GHz Implantable OOK Transmitter for Wireless Biotelemetry Systems: In Vitro Experiments Using Rat Skin-Mimic

Dept. of Electr. & Comput. Eng., Washington State Univ., Pullman, WA, USA
IEEE Transactions on Microwave Theory and Techniques (Impact Factor: 2.94). 01/2011; DOI: 10.1109/TMTT.2010.2088137
Source: IEEE Xplore

ABSTRACT A wireless biotelemetry system operates in vivo, which requires low power consumption for long-lasting operation, high output power for long transferable distance, and high throughput for incorporating many recording electrodes and transmitting raw brain signals. An implantable 2.4-GHz on-off keying (OOK) transmitter with high throughput and high energy efficiency for wireless biotelemetry systems has been designed in a 0.18-μm CMOS process. To balance power consumption and output power, a complementary voltage-controlled oscillator for the proposed transmitter is employed. Power consumption of the transmitter is reduced by switching the oscillator on and off to generate an OOK modulated signal. The transient delay for the transmitter is derived and applied to implement a high throughput transmitter. Rat skin-mimic emulating the implant environment such as electrical properties of the skin is used to measure the proposed transmitter in vitro. To transmit 136 Mb/s of OOK data, the transmitter consumes 3 mW of dc power and generates an output power of -14 dBm. The transmitter achieves energy efficiency of 22 pJ/bit with an associated bit error rate of 1.7 × 10- 3 without using an error correction scheme.

0 Followers
 · 
107 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: A low power on-off mode resonant tunneling diode (RTD) based oscillator is demonstrated by using an RTD/heterojunction bipolar transistor (HBT) MMIC technology. Using the negative differential resistance (NDR) characteristics of the tunneling diode, which arise at a low applied voltage range from the quantum-effect, the low power oscillators are used for microwave on-off keying (OOK) signal modulation. The fabricated RTD-based oscillator shows low power consumption of 5 mW at an oscillation frequency of 5.2 GHz. The RTD-based oscillator operates in an on-off mode with a high data rate of 1 Gb/s from the fast switching capabilities of the RTD and HBT switch. A good energy efficiency of 5 pJ/bit has been obtained in this work.
    2014 26th International Conference on Indium Phosphide and Related Materials (IPRM); 05/2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work, we show the realization of a fully-implantable device for monitoring free-moving small animals. The device integrates a microfabricated sensing platform, a coil for power and data transmission and two custom designed integrated circuits. The device is intended to be implanted in mice, free to move in a cage, to monitor the concentration of metabolites. We show the system level design of each block of the device, and we present the fabrication of the passive sensing platform and its employment for the electrochemical detection of endogenous and exogenous metabolites. Moreover, we describe the assembly of the device to test the biocompatibility of the materials used for the microfabrication. To ensure biocompatibility, an epoxy enhanced polyurethane membrane was used to cover the device. We proved through an in-vitro characterization that the membrane was capable to retain enzyme activity up to 35 days. After 30 days of implant in mice, in-vivo experiments proved that the membrane promotes the integration of the sensor with the surrounding tissue, as demonstrated by the low inflammation level at the implant site.
    IEEE Transactions on Biomedical Circuits and Systems 10/2014; 8(5). DOI:10.1109/TBCAS.2014.2359094 · 3.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A 2.4-GHz CMOS on-off keying (OOK) transmitter is developed for applications that require high data rate over 10Mbps in the area of wireless body area network (WBAN) and medical implant communication service (MICS). A novel analog pulse-shaping circuit for reducing power consumption and circuit complexity is employed for the OOK transmitter. Fabricated in 0.13 mu m CMOS, the transmitter core excluding the 50 ohm driving buffer dissipates 0.95mWfrom 1.2-V supply. Measurement shows that it can support the data rate up to 22 Mbps. With the pulse-shaping capability enabled, the transmitter output spectrum shows successful suppression of the sidelobe power below -42 dBc at 100MHz offset from the center frequency.
    IEICE Electronics Express 06/2011; 8(11):825-829. DOI:10.1587/elex.8.825 · 0.39 Impact Factor