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Biosensors transform physiological or biological information into electrical measurements using electronic circuits. The detected information is transmitted remotely to a data acquisition platform or a server using a wireless link for real-time monitoring and analysis. The main applications of biosensors are in wearable and implantable biomedical devices. The label-free biosensors using electrochemical and electrical transduction mechanisms such as potentiometric, amperometric, field-effect transistor, resistive, capacitive, and inductive can be developed in a small package to enable miniature point-of-care devices. The electrical properties of the biosensors are converted into voltage, frequency, or phase using various interface or readout circuit techniques. This chapter discusses the design of biosensors with wireless links for implantable or wearable sensors. A complete design example including a capacitive pH-sensor device will be discussed. The recent developments of implantable or wearable sensors using a wireless link, such as implanted wireless blood-glucose sensors, wireless capsules, and other wireless wearable devices will be presented.

Deep brain stimulation is an effective surgical treatment for advanced Parkinson's disease in patients whose symptoms are not well controlled by drugs. The subthalamic nucleus (STN), the globus pallidus pars externa (GPe), and the globus pallidus pars interna (GPi) are the targets for DBS. Despite over a decade of the practical clinical experience, the selections of DBS parameters are still challenging. DBS affects the local cells within the target site as well as the passing axons within neighboring regions. A computational model of basal ganglia-thalamic network is formed to analyze the performance of DBS at STN, GPe, and GPi in terms of error index. In addition to single-site stimulation, multiple-site stimulation is also analyzed for DBS of STN-GPe and STN-GPi in terms of error index. The goal of this work is to use computational modeling to analyze the effect of DBS of single-site stimulation (STN, GPe, or GPi) and multiple-site stimulation (STN-GPe or STN-GPi) with respect to stimulation amplitude and frequency.

Although conventional cryptographic security mechanisms are essential to the overall problem of security, the openness of wireless medium poses both threats and opportunities for securing transmission. Information theoretic security is attracting researchers for its robust nature. In this paper, a Gaussian multiple input multiple output multiple eavesdropper (MIMOME) channel is considered where a transmitter is communicating to a receiver in the presence of an eavesdropper. The transmitter is equipped with multiple antennas, while the receiver and the eavesdropper also contains multiple antennas. We present a technique for determining the secrecy capacity of the MIMO channel under Gaussian noise. To do so, we transform the channel into multiple single input multiple output (SIMO) Gaussian wiretap channel and then use scalar approach using standard techniques of communications theory. Then we consider the effect of fading and found out the limiting values of the secrecy capacity.