Design of a capacitively loaded implantable loop antenna in the cerebral spinal fluid

A capacitively loaded implantable loop antenna operating at 400 MHz is proposed for the implantation in the cerebral spinal fluid (CSF) above the brain. The specific absorption rate and temperature analysis were carried out to investigate the maximum input power for the implantable antenna without violating the safety considerations inside an anatomical realistic human head model. The implantable antenna achieves a maximum input power of 15.7 mW with 1 degrees C increase in the temperature of the human head tissue. Thus, the implantable antenna can be integrated with a low-power RF neural module

Resonance sensitivity and quality factor of implantable loop antenna loaded with interdigital capacitor in the cerebral spinal fluid

The design of an implantable loop antenna loaded with an interdigital capacitor operating at 400 MHz is presented. The sensitivity of the resonance change due to the change of the dielectric constant of the implantation tissue is studied and assessed via numerical simulations. The perturbation of the electric field affects the capacitance and thereby the input impedance of the antenna. In this manner, the antenna can be used to sense the dielectric constant changes of the implantation tissue. Despite the adverse effect of the cerebral spinal fluid (CSF) on the quality factor (Q) of the implantable antenna, a resonance shift of 25:2 MHz is obtained when the dielectric constant is increased by 14% from the nominal values

Design of a miniaturized circular implantable antenna

The design of a new miniaturized circular implantable antenna at 1 GHz is presented along with the near-field radiation performance inside the human skin. For minimally invasive antenna inside the human head, the skin has been selected as the implantation tissue. To effectively miniaturize the antenna, unequal cross slots with shortening pin have been added to achieve a total volume of 185mm3. The antenna is encapsulated in a cylindrical biocompatible alumina substrate and superstrate. The proposed antenna is designed to operate at frequency around 1GHz to achieve good penetration in the human head with low signal attenuation. E-field distribution in the reactive near-field infront of the surface of the antenna has been assessed at different radial distance to investigate the strength with distance variation. To abide with IEEE standards for specific absorption rate (SAR), the maximum input power has been derived along with SAR simulation in xy, xz and yz planes

Compact meander tapered patch antenna for wireless biomedical telemetry

The design of an implantable equilateral triangle patch antenna is presented. The patch is tapered with narrow slits to meander the current path to lower the resonant frequency to 402MHz. By changing the length and width of narrow slits and adding a shortening pin, a compact size of the antenna is achieved, which is around 141mm. Two implantation setups are considered. The antenna has been initially designed inside a skin cube and a 3-D spherical head model taking into account the effect of exterior air. The performance of the antenna is characterized in terms of the reflection coefficient, the far field radiation pattern, the specific absorption rate (SAR) as well as the axial ratio for both implantation setups

Full-view coverage quasi-mobile camera sensor network for maritime surveillance

Coverage of a camera sensor network (CSN) is a critical issue in deploying such network in maritime environment. In such environment, camera sensors will not be stationary after the initial deployment due to the hostile sea environment. Hence, the mobility pattern poses a major limitation on identifying the time-varying coverage. In full-view coverage, target's facing direction has been introduced to judge whether a target's facing direction is guaranteed to be captured. To this end, we exploit full-view coverage in CSN, since image shots at the frontal viewpoint of a given target considerably increase the possibility to detect and recognize the target. In this paper, we have developed a mobility pattern based on wind speed and spring relaxation technique which are used to characterize the total displacement of a given buoy. Furthermore, the average percentage of full-view coverage has been evaluated based on different parameters such as equilateral triangle grid length, sensing radius of camera, wind speed and wave height. Consequently, the proposed model has been validated through MATLAB simulation platform

An analysis of uncovered area for camera sensor network in maritime environment

Nowadays, accurate and low-cost autonomous maritime surveillance of camera sensor network is a critical requirement for various applications. In a maritime environment, camera sensors are deployed on mobile platforms, such as buoys. With an anchored buoy architecture, sensor locations are quasistationary. When sensors move, some areas may not be covered at some times. This paper analyzes the extend of the uncovered area in a realistic maritime environment. We present numerical results to variation in uncovered areas from time to time. Also in this paper, the simulation of the uncovered area detection of camera sensor network (CSN) used in maritime surveillance is presented using MATLAB

Effect of realistic sea surface movements in achieving full-view coverage camera sensor network

In stationary camera sensor networks (CSNs), when the deployment characteristics and sensing models are defined, the coverage can be deduced and remain unchanged over time. However, in the maritime environment, the rough and random sea condition can move CSN from the initial location. We envisage that camera sensors are mounted on quasi‐mobile platforms such as buoys. Hence, it is important to understand the effect of realistic sea surface movements in achieving full‐view coverage because in full‐view coverage, target's facing direction is taken into account to judge whether a target is guaranteed to be captured because image shot at the frontal viewpoint of a given target considerably increases the possibility to detect and recognize the target. To accurately emulate the maritime environment, the movement of the buoy, which is attached with a cable that is nailed at the sea floor, has been characterized based on the sea wave that is created by the wind, and it is limited by the cable. The average percentage of full‐view coverage has been evaluated based on different parameters such as equilateral triangle grid length, sensing radius of camera, wind speed and wave height. Furthermore, a method to improve the target detection and recognition has been proposed in the presence of poor link quality using cooperative transmission with low power consumption. In some parameter scenario, the cooperative transmission method has achieved around 70% improvement in the average percentage of full‐view coverage of a given target and total reduction of around 13% for the total transmission power PTotal(Q)

An overview of maritime wireless mesh communication technologies and protocols

Maritime wireless mesh networks (MWMNs) are conceived to provide network connectivity for maritime users and enable them to communicate with correspondent users connected to terrestrial communication networks. The high cost and low data-rate of satellite and other legacy maritime communication technologies and systems deployed in MWMNs pose major limitation to establish reliable and affordable maritime communications. In addition, the design of routing protocols in MWMNs remains a significant challenge due to the lack of reliable communication infrastructure and complexity of maritime environment. This paper explains the existing maritime communication technologies and routing protocols which could be deployed in implementing reliable MWMNs. Comprehensive guidelines are outlined to easily understand and critically assess the different deployed maritime communication networks and systems with routing protocols, and identify the milestones in the process of developing and implementing broadband MWMNs