The rapid increase in healthcare demand has seen novel developments in health monitoring technologies, such as the body area networks (BAN) paradigm. BAN technology envisions a network of continuously operating sensors, which measure critical physical and physiological parameters e.g., mobility, heart rate, and glucose levels. Wireless connectivity in BAN technology is key to its success as it grants portability and flexibility to the user. While radio frequency (RF) wireless technology has been successfully deployed in most BAN implementations, they consume a lot of battery power, are susceptible to electromagnetic interference and have security issues. Intrabody communication (IBC) is an alternative wireless communication technology which uses the human body as the signal propagation medium. IBC has characteristics that could naturally address the issues with RF for BAN technology. This survey examines the on-going research in this area and highlights IBC core fundamentals, current mathematical models of the human body, IBC transceiver designs, and the remaining research challenges to be addressed. IBC has exciting prospects for making BAN technologies more practical in the future.

A Survey on Intrabody Communications for Body Area Network Applications

This paper describes a fractional-N PLL IC based on a new digital quantizer that replaces the DeltaSigma modulator (DeltaSigmaM) used in conventional designs. In combination with a charge pump offset technique and a sampled loop filter the new quantizer enables state-of-the-art fractional spur performance without sacrificing BW.

Spurious -Tone Suppression Techniques Applied to a Wide-Bandwidth 2.4GHz Fractional-N PLL

This paper demonstrates that spurious tones in the output of a fractional-N PLL can be reduced by replacing the DeltaSigma modulator with a new type of digital quantizer and adding a charge pump offset combined with a sampled loop filter. It describes the underlying mechanisms of the spurious tones, proposes techniques that mitigate the effects of the mechanisms, and presents a phase noise cancelling 2.4 GHz ISM-band CMOS PLL that demonstrates the techniques. The PLL has a 975 kHz loop bandwidth and a 12 MHz reference. Its phase noise has a worst-case reference spur power of - 70 dBc and a worst-case in-band fractional spur power of -64 dBc.

Spurious Tone Suppression Techniques Applied to a Wide-Bandwidth 2.4 GHz Fractional- N PLL

A software-defined radio (SDR) should theoretically receive any modulated frequency channel in the (un)licensed spectrum, and guarantee top performance with energy savings, while still being integrated in a digital CMOS technology. This paper demonstrates a practical 0.1-5 GHz front-end implementation for such an SDR concept, including receiver and local oscillator (LO), with only 2-mm2 core area occupation in a 45-nm CMOS process. This scalable radio uses shunt-shunt feedback LNAs, a passive mixer with enhanced out-of-band IIP3, and a fifth order low-area 0.5-20 MHz baseband filter. LO quadrature signals are generated from a dual-VCO 4-10 GHz fractional-N PLL. With noise figure between 2.3 dB and 6.5 dB, out-of-band IIP3 between -3 dBm and -10 dBm, and total power consumption between 59 and 115 mW from a 1.1-V supply voltage, the presented prototype favorably compares with state-of-the-art dedicated radios while enabling, for the first time, wideband reconfigurable performance and energy scalability.

A 2-mm $^{2}$ 0.1–5 GHz Software-Defined Radio Receiver in 45-nm Digital CMOS

Micro-electromechanical systems (MEMS) use microminiature sensors and actuators. MEMS technology provides the benefits of small size, low weight, high performance, easy mass-production and low cost. This article is the first part of a three-part series on MEMS sensors. In the present article, we provide a general introduction to MEMS sensing and the primary sensing techniques. Next, MEMS-based bio-medical sensors are explained. We consider MEMS devices that are: designed to detect triglycerides, c-reactive protein, and glucose, respectively; bio-inspired robotic fingers with tissue softness characterization sensors for pressure measurement during surgical procedures; for counting blood cells; acoustic sensors for 2-D sound source localization; pressure measurement sensors on the wings of an insect-like flying robot; and ultra-miniature sensors for intramuscular pressure measurement. The second part of the series will be dedicated to mechanical sensors. There, some related technologies of MEMS sensors will be discussed including compensation for environmental effects, the Casimir effect, and harvesting of energy for self-powered sensors. Also, the subject of sensor selection will be addressed. The third part will treat MEMS sensing in the thermo-fluid and electro-magnetic domains.

Recent advances in MEMS sensor technology – biomedical applications

The first circuit implementation of quantization noise suppression technique for DeltaSigma fractional- N frequency synthesizers using reduced step size of frequency dividers is presented in this paper. This technique is based on a 1/1.5 divider cell which can reduce the step size of the frequency divider to 0.5 and thus the reduced step size suppresses the quantization noise by 6 dB. This frequency synthesizer is intended for a WLAN 802.11a/WiMAX 802.16e transceiver. This chip is implemented in a 0.18-mum CMOS process and the die size is 1.23 mm times 0.83 mm. The power consumption is 47.8 mW. The in-band phase noise of -100 dBc/Hz at 10 kHz offset and out-of-band phase noise of -124 dBc/Hz at 1MHz offset are measured with a loop bandwidth of 200 kHz. The frequency resolution is less than 1 Hz and the lock time is smaller than 10 mus

A Quantization Noise Suppression Technique for $DeltaSigma$ Fractional- $N$ Frequency Synthesizers

A quick wireless label-free detection of disease-related C-reactive proteins (CRPs) using a 200-mum-long microelectromechanical systems (MEMS) microcantilever housed in a 7times7 mm2 reaction chamber with a safe reusable feature is reported. The assay time ranges from about 30 min to 3 h, depending on accuracy. The deflection of the microcantilever due to specific CRP-antiCRP binding is detected using a position-sensitive detector. The converted bio-signal is transmitted by a custom designed wireless amplitude-shift-keying (ASK) transceiver IC fabricated in a 0.18 mum CMOS process. CRP concentrations from 1 mug/mL to 500 mug/mL can be detected. A 0.2-Hz 1-V ac signal instead of traditional bases/acids is applied to the bio-MEMS sensor to unbind the CRP from the microcantilever for reusability.

A Wireless Bio-MEMS Sensor for C-Reactive Protein Detection Based on Nanomechanics

A low-voltage (0.5 V) and low-power (4.535 mW) monolithic biomedical system-on-a-chip (SOC) consisting of a receiver, a transmitter, a microcontrol unit, and an analog-to-digital converter (ADC), implemented in a 0.18-μm CMOS technology for intrabody communication is first reported. The SOC can take command through a human body and activate (or turn on) the ADC and transmitter inside the SOC. Then, a biomedical signal is converted to digital format and transmitted to the RF gateway through a human body. With this transmission methodology and the proposed SOC circuit, it is much more power efficient than wireless communication. Moreover, since no antenna is required, the chip size of the SOC is only 1.5 mm2, excluding the test pads.

A 0.5-V Biomedical System-on-a-Chip for Intrabody Communication System

A quick (<30min.), label-free detection of disease-related C-reactive proteins (CRP) is achieved using a 200mum MEMS microcantilever housed in a 7times7mm2 reaction chamber. The deflection of the cantilever due to specific CRP/anti-CRP binding is detected using a position-sensitive photodiode and the converted bio-signal is transmitted by a wireless ASK transceiver IC fabricated in a 0.18mum CMOS process. CRP concentrations from 1mug/mL to 500mug/mL can be detected. A 0.2Hz 1V ac signal is applied to the bio-MEMS sensor to unbind CRP from the cantilever for reuse

The provided fractional frequency divider includes a divider controlling unit for generating a divider selection signal in response to a dual-edge triggering of an input signal and a frequency dividing unit coupled to the divider controlling unit for dividing the frequency of the input signal by one of an integer and a fractional dividers in response to the dual-edge triggering and the divider selection signal to generate the output signal of the fractional frequency divider. An operation of the frequency dividing unit is not suppressed when the integer divider is employed, the operation of the frequency dividing unit is not suppressed for a period of the input signal and is suppressed for half of that period, and this cycle is kept on recurring when the fractional divider is employed. The fractional-n PLL having the fractional frequency divider is also provided.

Yu-Che Yang

Papers

A Quantization Noise Suppression Technique for $DeltaSigma$ Fractional- $N$ Frequency Synthesizers

A Wireless Bio-MEMS Sensor for C-Reactive Protein Detection Based on Nanomechanics

A 0.5-V Biomedical System-on-a-Chip for Intrabody Communication System

A Wireless Bio-MEMS Sensor for C-Reactive Protein Detection Based on Nanomechanics

Configuration and controlling method of fractional-N PLL having fractional frequency divider