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This article describes how, in recent years, with the development of microelectronics, implantable electronic devices have been playing a significant role in modem medicine. Examples of such electronic implant devices are, for instance, retinal prosthesis and brain implants. It brings great challenges in low power radio frequency (RF) and analog designs. This article presents a low power Gaussian frequency shift keying (GFSK) demodulator designed for Medical Implant Communications Service (MICS) band Receiver. This demodulator utilizes a novel structure that a wide IF range can be handled and presents the smallest Δf/f ratio in any published GFSK demodulators. In theory the demodulation method can be applied to any RF frequency. The demodulator draws 550uA from a 1 V power supply. A maximum data rate of 400 Kbits/s can be achieved within the 300 KHz channel bandwidth defined by MICS. A simulated signal-to-noise ratio (SNR) of 15.2dB at AWGN channel is obtained to achieve 10-3 bit error rate (BER). This demodulator is fabricated on 65-nm CMOS and occupies 0.12mm2 silicon area.

A compact silicon photonic grating coupler enabling fiber-to-chip light coupling at a minimized footprint is proposed. The proposed coupler, which is partially overlaid at the tapered region, downsizes the effective length of the spot-size converter to 60 μm while reducing the lateral height and width adiabatically to 220 nm and 320 nm, respectively. The incorporation of such a coupler in a photonic integrated circuit requires a total physical length and width of 75 μm and 14 μm, respectively, to enable effective interfacing with single mode fiber. The coupling efficiency and bandwidth of the structure at the light wavelength of 1550 nm are quantified as 68% and 67 nm, respectively, which outperform most recent demonstrations.

A performance enhanced butt coupling structure incorporating a vertically and laterally tapered SiON polymer core on silicon (Si) to tunnel and widen propagating optical modes of adiabatic taper is proposed. The proposed structure can effectively overcome the strong back reflections caused at the interface between fiber and Si nanowire to enable higher coupling efficiency. The placement of the SiON polymer core is chosen to restrict the passage of light through the bottom cladding to avoid unnecessary leakage. The performance of the structure is characterized for distinct features, including taping length, coupling efficiency, and coupling bandwidth for both single as well as cacaded configurations, compared with the state-of-the-art grating coupler. It is found that, with the right set of design specifications, butt couplers can outperform grating couplers in both coupling efficiency and bandwidth, although grating couplers are considered friendlier for wafer-level testing.

Nanophotonic technologies have attracted a lot of attention to co-develop optical and electronic devices on silicon (Si) that further miniaturize modern optical communication systems. Optical properties of these miniaturized devices are highly dependent on waveguide geometry and can be tailored for various applications with minor changes in cross-sectional areas. This paper investigates the performance of widely discussed planar, rib, and photonic crystal Si waveguides by manipulating the dimensions of Si core designed for single mode operation across the 1.2 to 1.6 μm telecommunication bands. Each of the waveguide is studied and compared for a set of properties, including effective refractive index, group index, group-velocity dispersion, and mode loss, with and without narrow bends, which can be instrumental in selecting the correct type and geometry of the waveguide required for any specific application.

Recent advances in semiconductor fabrication are providing the opportunity to build very small and cost-effective single chip integrated radar systems operating at millimeter-wave frequencies and beyond. These tiny radar systems will enable a wide range of new applications such as automotive radar, safety helmet radar, robot guidance radar, UAV collision avoidance and mapping radar, bicycle safety radar, and many other possibilities. Considerable progress has been made in designing and building such systems; however, many challenges remain related to limitations imposed by radio frequency IC technology such as Complementary Metal Oxide Semiconductors (CMOS) including modest dynamic range and modest noise figure for low noise amplifies (LNAs), oscillator phase noise, limited transmit power, etc. There is also likely to be a significant interference challenge arising from large numbers of small radars operating in close spatial and spectral proximity in many of the envisioned applications. In this chapter we present an overview of some of the design challenges facing millimeter-wave radar, and shed light on recent advances in system design and signal processing techniques, including adaptive waveform scheduling and interference mitigation. Advances in signal processing will allow multiple radars to operate in an uncoordinated manner with limited processing power using adaptive waveform scheduling, that leads to better interference mitigation and higher ranging performance. We present some properties of the millimeter-wave spectrum and investigate ray-tracing methods as an efficient, accurate, and rapid testing platform for consumer radars applications, where we develop a ray-tracing propagation model for automotive radar operating in an urban environment. Also, we introduce novel tools from stochastic geometry to characterize the statistics of the interference resulting from many radars sharing the same spectrum in a particular location. Specifically, we study automotive radar applications and obtain interference statistics and the estimated detection performance. Finally, we briefly discuss certain fundamental limitations imposed on radar system capabilities, by CMOS technology and by the information carrying capacity of electromagnetic waves.

A single mode waveguide grating coupler based on multiple Si–SiO2 pairs onto Si substrate has been designed. Numerical analysis has been carried out to calculate optimum thickness of the layers of Si–SiO2 that ensures the constructive interference between reflected waves and actual guided wave for high coupling efficiency. Based on the results, an optimal design is developed and modeled by using a 2-D finite difference time domain simulator that dictates a coupling efficiency of as much as 78 % (−1.07 dB) at the wavelength of 1550 nm, and a 1-dB bandwidth of 77 nm. The numerical method will be useful to calculate the optimum thicknesses of the layers for any reflector based grating coupler of different materials.

A single mode waveguide grating coupler based on multiple Si-SiO2 pairs onto Si substrate has been designed. Numerical analysis has been carried out to calculate optimum thickness of the layers of Si-SiO2 that ensures the constructive interference between reflected waves and actual guided wave for high coupling efficiency. Based on the results, an optimal design is developed and modeled by using a 2-D finite difference time domain (2-D FDTD) simulator that dictates a coupling efficiency of as much as 78% (-1.07 dB) at the wavelength of 1550 nm, and a 1-dB bandwidth of 77 nm. The numerical method will be useful to calculate the optimum thicknesses of the layers for any reflector based grating coupler of different materials.

An ultra-low-power wireless transmitter for embedded bionic systems is proposed, which achieves 40 pJ/b energy efficiency and delivers 500 kb/s data using the medical implant communication service frequency band (402-405 MHz). It consumes a measured peak power of 200 µW from a 1.2 V supply while occupying an active area of 0.0016 mm(2) in a 130 nm technology. A modified pulse position modulation technique called saturated amplified signal is proposed and implemented, which can reduce the overall and per bit transferred power consumption of the transmitter while reducing the complexity of the transmitter architectures, and hence potentially shrinking the size of the implemented circuitry. The design is capable of being fully integrated on single-chip solutions for surgically implanted bionic systems, wearable devices and neural embedded systems.

Frequency reference and timing control devices are ubiquitous in electronic applications. There is at least one resonator required for each of this device. Currently electromechanical resonators such as crystal resonator, ceramic resonator are the ultimate choices. This tendency will probably keep going for many more years. However, current market demands for small size, low power consumption, cheap and reliable products, has divulged many limitations of this type of resonators. They cannot be integrated into standard CMOS (Complement metaloxide- semiconductor) IC (Integrated Circuit) due to material and fabrication process incompatibility. Currently, these devices are off-chip and they require external circuitries to interface with the ICs. This configuration significantly increases the overall size and cost of the entire electronic system. In addition, extra external connection, especially at high frequency, will potentially create negative impacts on the performance of the entire system due to signal degradation and parasitic effects. Furthermore, due to off-chip packaging nature, these devices are quite expensive, particularly for high frequency and high quality factor devices. To address these issues, researchers have been intensively studying on an alternative for type of resonator by utilizing the new emerging MEMS (Micro-electro-mechanical systems) technology. Recent progress in this field has demonstrated a MEMS resonator with resonant frequency of 2.97 GHz and quality factor (measured in vacuum) of 42900. Despite this great achievement, this prototype is still far from being fully integrated into CMOS system due to incompatibility in fabrication process and its high series motional impedance. On the other hand, fully integrated MEMS resonator had been demonstrated but at lower frequency and quality factor. We propose a design and fabrication process for a low cost, high frequency and a high quality MEMS resonator, which can be integrated into a standard CMOS IC. This device is expected to operate in hundreds of Mhz frequency range; quality factor surpasses 10000 and series motional impedance low enough that could be matching into conventional system without enormous effort. This MEMS resonator can be used in the design of many blocks in wireless and RF (Radio Frequency) systems such as low phase noise oscillator, band pass filter, power amplifier and in many sensing application.

Point-of-care molecular diagnostic devices are a rapidly expanding market. A variety of technologies are being developed for DNA detection and amplification, mostly aiming to detect pathogens. Of the two devices for detection of human genetic variations, both focus on CYP2C19 and have obtained regulatory approval. Most other devices have not obtained US FDA approval and are still undergoing clinical trials. Most, if not all, devices in development require equipment to which disposable test cartridges are placed. Thus, they may not fulfill FDA's definition of being ‘simple’. There is a clear need to develop completely disposable devices that do not require equipment maintenance, and to detect other genetic variants predictive of disease susceptibility and drug response.

Employing integrated nano- and microfluidic circuits for detecting and characterizing biological compounds through resistive pulse sensing technology is a vibrant area of research at the interface of biotechnology and nanotechnology. Resistive pulse sensing platforms can be customized to study virtually any particle of choice which can be threaded through a fluidic channel and enable label-free single-particle interrogation with the primary read-out signal being an electric current fingerprint. The ability to perform label-free molecular screening with single-molecule and even single binding site resolution makes resistive pulse sensing technology a powerful tool for analyzing the smallest units of biological systems and how they interact with each other on a molecular level. This task is at the core of experimental systems biology and in particular 'omics research which in combination with next-generation DNA-sequencing and next-generation drug discovery and design forms the foundation of a novel disruptive medical paradigm commonly referred to as personalized medicine or precision medicine. DNA-sequencing has approached the 1000-Dollar-Genome milestone allowing for decoding a complete human genome with unmatched speed and at low cost. Increased sequencing efficiency yields massive amounts of genomic data. Analyzing this data in combination with medical and biometric health data eventually enables understanding the pathways from individual genes to physiological functions. Access to this information triggers fundamental questions for doctors and patients alike: what are the chances of an outbreak for a specific disease? Can individual risks be managed and if so how? Which drugs are available and how should they be applied? Could a new drug be tailored to an individual's genetic predisposition fast and in an affordable way? In order to provide answers and real-life value to patients, the rapid evolvement of novel computing approaches for analyzing big data in systems genomics has to be accompanied by an equally strong effort to develop next-generation DNA-sequencing and next-generation drug screening and design platforms. In that context lab-on-a-chip devices utilizing nanopore- and nanochannel based resistive pulse-sensing technology for DNA-sequencing and protein screening applications occupy a key role. This paper describes the status quo of resistive pulse sensing technology for these two application areas with a special focus on current technology trends and challenges ahead.

We present an ultra-compact metal reflector based grating coupler for coupling light between optical fiber and nano photonic waveguides. The coupler is designed and simulated based on Finite Difference Time Domain (FDTD) method. The lateral dimension of the grating waveguide has been tapered down from 10 µm to 400 nm within 8 µm length to interface with nano photonic waveguides using half overlay triangular waveguides. We have achieved a coupling efficiency of 94% (−0.25dB) using metal reflector and after the cascaded triangular waveguides, the efficiency remains as high as 80% (−0.95dB) with 1-dB bandwidth of 80 nm. The total length of the coupler is as low as 24 µm which provides very small foot print in silicon (Si) photonic ICs.

Optical delay and corresponding group index of structure composed of slab waveguide coupled with slotted ring resonator are investigated in this paper. Ring resonators have attracted a lot of attention to develop optical delay line which has numerous applications in communication. Properties of these micro ring resonators are highly dependent on waveguide geometry and can be tailored for various applications with minor changes. This paper investigates performance of single and multi stage ring resonators by manipulating geometry and gap between slab and ring waveguide for single mode propagation which may assist to make well informed decisions in the selection process of best-suited ring waveguide for particular application. This investigation is further extended to verify the tolerance of the design in case of fabrication errors with dimension of ±10nm.

Change in refractive index and corresponding change in optical properties like propagation loss, group index and dispersion in active PIN silicon waveguide with and without photonic crystal core are investigated by changing doping concentration. This investigation sets a bound on doping density which is utilized to change effective refractive index for various applications like modulation, switching, dispersion compensation, slowing light and so on. Influences of depleting carriers on junction capacitance and reverse current behaviors are also investigated for same waveguides. This sets a benchmark for the design and selection of appropriate waveguide for various applications in silicon photonics platform.

Designing a wireless power transmission system(WPTS) using inductive coupling has been investigated extensively in the last decade. Depending on the different configurations of the coupling system, there have been various designing methods to optimise the power transmission efficiency based on the tuning circuitry, quality factor optimisation and geometrical configuration. Recently, a 3-coil WPTS was introduced in retinal prosthesis to overcome the low power transferring efficiency due to low coupling coefficient. Here we present a method to analyse this 3-coil WPTS using the S-parameters to directly obtain maximum achievable power transferring efficiency. Through electromagnetic simulation, we brought a question on the condition of improvement using 3-coil WPTS in powering retinal prosthesis.

Changes in refractive index and the corresponding changes in the characteristics of an optical waveguide in enabling propagation of light are the basis for many modern silicon photonic devices. Optical properties of these active nanoscale waveguides are sensitive to the little changes in geometry, external injection/biasing, and doping profiles, and can be crucial in design and manufacturing processes. This paper brings the active silicon waveguide for complete characterization of various distinctive guiding parameters, including perturbation in real and imaginary refractive index, mode loss, group velocity dispersion, and bending loss, which can be instrumental in developing optimal design specifications for various application-centric active silicon waveguides.

One promising path for future drug screening technologies is to examine the binding of ligands to target proteinsat the single molecule level by passing them through nanometer sized pores and measuring the change in porecurrent during translocation. With the aim of evaluating such technologies we perform virtual experiments onthe translocation of proteins through silicon nitride nanopores. These simulations consist of large scale, fullyatomistic models of the translocation process that involve steering a test protein through the nanopore on atimescale of tens of nanoseconds. We make a comparison between theoretically expected and simulated values ofthe current drop that is seen when the protein occupies the pore. Details of the stability of the protein and thepreservation of its function as measured by its secondary and tertiary structure will be presented to validate boththe simulation results and the fundamental design of the proposed device. Finally, the results will be placed inthe context of experimental work that combines nanofabrication and microuidics to create a high throughput,low cost, drug screening device.Keywords: nanosensors, single molecule sensing, molecular dynamics, molecular simulation, drug screening,nanotechnology, microuidics

In this paper, we present a flexible biphasic pulse generating and accurate charge balancing stimulator with a 1μW neural recording amplifier. To achieve accurate charge balance, the stimulator is implemented using a dynamic current copying technique. It can generate a biphasic current pulse with an anodic scaling feature. To reduce power consumption, the recording amplifier is implemented to operate with 1V, while the stimulator works with 3V supply. They are implemented using a 65nm CMOS process. Simulation results show charge balance of less than 2% error in current pulses. The recording amplifier has an input referred noise of 4.5μVrms and passband from 1.5Hz to 5KHz with the power consumption of 1μW.

In this paper, we present a precise charge balancing and compliance voltage monitoring stimulator front-end for 1024-electrode retinal prosthesis. Our stimulator is based on current mode stimulation. To generate a precisely matched biphasic current pulse, a dynamic current copying technique is applied at the stimulator front-end. A compliance voltage monitoring circuitry is included at the stimulator front-end to detect if a voltage across electrode-tissue interface goes beyond a predefined compliance voltage. Simulation results show the mismatch of a biphasic current pulse (at a maximum stimulation current of 476µA) is less than 0.1%. Also, the stimulator issues alarm signals, when a voltage compliance occurs during stimulation due to high tissue impedance. Our stimulator is implemented using a 65nm low voltage (LV) CMOS process, which helps reducing implementation area and power consumption.

The recent proliferation of modern portable devices and applications demands to deploy in-house high-speed Internet on the move. Millimeter-wave (mm-wave) wireless with its inherent multi-Gb/s capacities is seen as an alternative to fiber-to-the-home (FTTH) that has benchmarked the access of future Internet through fiber. This paper investigates a suitable approach to interface FTTH with mm-waves that enables in-house transparent and seamless access to Internet on the move through cordless access to FTTH. In such case, in addition to fixed point access, in-house optical network unit (ONU) establishes mm-wave cordless communications without any translation of FTTH data or modulation format.

In this paper, we present a low-power, small-area and programmable bandgap reference, based on the reverse bandgap reference concept. It is implemented in a 65nm digital CMOS process with 1.2V power supply. It employs two switched capacitor amplifiers to weight temperature dependent voltages with opposite polarity. Programmability is achieved by adjusting a closed-loop gain of these two amplifiers. The implemented BGR generates three reference voltages, such as 0.591V (V REF1 ), 0.872V (V REF2 ) and 1.189V (V REF3 ). In simulation, with ±10% supply voltage variation, the temperature coefficient (TC) of V REF1 , V REF2 and V REF3 is less than 43ppm/°C, 28ppm/°C and 33ppm/°C, respectivley, in the temperature range from −40°C to 100°C. The average power consumption is less than 40µW for V REF1 , 60µW for V REF2 and 110µW for V REF3 . The layout area (excluding bonding pads) is 200µm by 190µm.

An ultra wide dynamic range voltage reference operating with power consumption of pico-watt has been designed for a retinal prosthesis device using IBM 65nm CMOS process. The temperature coefficient is zeroed at 37 °C while achieving 2.5 ppm/°C over the range from 25 °C to 75 °C. A perfect suppression of the supply voltage dependence is realised to provide line sensitivity of 0.04%/V with ultra low input voltage of 0.5 V up to 3.5 V. The power supply noise attenuation is simulated to maintain at 𢈒100 dB across whole frequency band up to 100GHz. The occupied chip area is maintained as low as 0.003 mm2 with size of 35µm by 75µm.

A modified ONU provisioning in-house mobility for FTTH customers is proposed and demonstrated. This scheme, in addition to fixed point access, distributes FTTH services wirelessly, potentially at equal speeds.

It is widely predicted that wireless sensor networks (WSNs) will proliferate in a vast range of potential applications including academic, industrial, agricultural, domestic and military. The purpose of this chapter is to indicate the ways in which the application affects the design of a wireless sensor network. We make use of the framework illustrated in Fig. 15.1. For any attribute of a wireless sensor network, it is the application, which determines the importance of that attribute in the design specification. The available technology then determines the manner in which that desired attribute might be achieved. The final design solution is then made by selecting from the allowable choices, tempered by other constraints such as cost. For example, considering the attribute of water-resistance, it may be that a particular outdoor application dictates the need for a water-resistant enclosure. Available technology then allows selection of an enclosure made from ABS plastic, polycarbonate, diecast aluminium or stainless steel. The actual selection might then be made on the basis of cost or weight. In this work we consider the manner in which the application dictates the design specification and also the possible design solutions allowed by current technology. The next section contains a list of the specific attributes that will be addressed. In the remainder of this chapter, each attribute is discussed in the context of application requirements and consequences in the context of hardware and software design are discussed. © Springer-Verlag Berlin Heidelberg 2007.